src/eval.c

/* vi:set ts=8 sts=4 sw=4 noet:
 *
 * VIM - Vi IMproved	by Bram Moolenaar
 *
 * Do ":help uganda"  in Vim to read copying and usage conditions.
 * Do ":help credits" in Vim to see a list of people who contributed.
 * See README.txt for an overview of the Vim source code.
 */

/*
 * eval.c: Expression evaluation.
 */
#define USING_FLOAT_STUFF

#include "vim.h"

#if defined(FEAT_EVAL) || defined(PROTO)

#ifdef VMS
# include <float.h>
#endif

#define DICT_MAXNEST 100	/* maximum nesting of lists and dicts */

static char *e_letunexp	= N_("E18: Unexpected characters in :let");
static char *e_undefvar = N_("E121: Undefined variable: %s");
static char *e_missbrac = N_("E111: Missing ']'");
static char *e_dictrange = N_("E719: Cannot use [:] with a Dictionary");
static char *e_letwrong = N_("E734: Wrong variable type for %s=");
static char *e_illvar = N_("E461: Illegal variable name: %s");
#ifdef FEAT_FLOAT
static char *e_float_as_string = N_("E806: using Float as a String");
#endif

#define NAMESPACE_CHAR	(char_u *)"abglstvw"

static dictitem_T	globvars_var;		/* variable used for g: */
#define globvarht globvardict.dv_hashtab

/*
 * Old Vim variables such as "v:version" are also available without the "v:".
 * Also in functions.  We need a special hashtable for them.
 */
static hashtab_T	compat_hashtab;

/*
 * When recursively copying lists and dicts we need to remember which ones we
 * have done to avoid endless recursiveness.  This unique ID is used for that.
 * The last bit is used for previous_funccal, ignored when comparing.
 */
static int current_copyID = 0;

/*
 * Array to hold the hashtab with variables local to each sourced script.
 * Each item holds a variable (nameless) that points to the dict_T.
 */
typedef struct
{
    dictitem_T	sv_var;
    dict_T	sv_dict;
} scriptvar_T;

static garray_T	    ga_scripts = {0, 0, sizeof(scriptvar_T *), 4, NULL};
#define SCRIPT_SV(id) (((scriptvar_T **)ga_scripts.ga_data)[(id) - 1])
#define SCRIPT_VARS(id) (SCRIPT_SV(id)->sv_dict.dv_hashtab)

static int echo_attr = 0;   /* attributes used for ":echo" */

/* The names of packages that once were loaded are remembered. */
static garray_T		ga_loaded = {0, 0, sizeof(char_u *), 4, NULL};

/*
 * Info used by a ":for" loop.
 */
typedef struct
{
    int		fi_semicolon;	/* TRUE if ending in '; var]' */
    int		fi_varcount;	/* nr of variables in the list */
    listwatch_T	fi_lw;		/* keep an eye on the item used. */
    list_T	*fi_list;	/* list being used */
} forinfo_T;


/*
 * Array to hold the value of v: variables.
 * The value is in a dictitem, so that it can also be used in the v: scope.
 * The reason to use this table anyway is for very quick access to the
 * variables with the VV_ defines.
 */

/* values for vv_flags: */
#define VV_COMPAT	1	/* compatible, also used without "v:" */
#define VV_RO		2	/* read-only */
#define VV_RO_SBX	4	/* read-only in the sandbox */

#define VV_NAME(s, t)	s, {{t, 0, {0}}, 0, {0}}

static struct vimvar
{
    char	*vv_name;	/* name of variable, without v: */
    dictitem16_T vv_di;		/* value and name for key (max 16 chars!) */
    char	vv_flags;	/* VV_COMPAT, VV_RO, VV_RO_SBX */
} vimvars[VV_LEN] =
{
    /*
     * The order here must match the VV_ defines in vim.h!
     * Initializing a union does not work, leave tv.vval empty to get zero's.
     */
    {VV_NAME("count",		 VAR_NUMBER), VV_COMPAT+VV_RO},
    {VV_NAME("count1",		 VAR_NUMBER), VV_RO},
    {VV_NAME("prevcount",	 VAR_NUMBER), VV_RO},
    {VV_NAME("errmsg",		 VAR_STRING), VV_COMPAT},
    {VV_NAME("warningmsg",	 VAR_STRING), 0},
    {VV_NAME("statusmsg",	 VAR_STRING), 0},
    {VV_NAME("shell_error",	 VAR_NUMBER), VV_COMPAT+VV_RO},
    {VV_NAME("this_session",	 VAR_STRING), VV_COMPAT},
    {VV_NAME("version",		 VAR_NUMBER), VV_COMPAT+VV_RO},
    {VV_NAME("lnum",		 VAR_NUMBER), VV_RO_SBX},
    {VV_NAME("termresponse",	 VAR_STRING), VV_RO},
    {VV_NAME("fname",		 VAR_STRING), VV_RO},
    {VV_NAME("lang",		 VAR_STRING), VV_RO},
    {VV_NAME("lc_time",		 VAR_STRING), VV_RO},
    {VV_NAME("ctype",		 VAR_STRING), VV_RO},
    {VV_NAME("charconvert_from", VAR_STRING), VV_RO},
    {VV_NAME("charconvert_to",	 VAR_STRING), VV_RO},
    {VV_NAME("fname_in",	 VAR_STRING), VV_RO},
    {VV_NAME("fname_out",	 VAR_STRING), VV_RO},
    {VV_NAME("fname_new",	 VAR_STRING), VV_RO},
    {VV_NAME("fname_diff",	 VAR_STRING), VV_RO},
    {VV_NAME("cmdarg",		 VAR_STRING), VV_RO},
    {VV_NAME("foldstart",	 VAR_NUMBER), VV_RO_SBX},
    {VV_NAME("foldend",		 VAR_NUMBER), VV_RO_SBX},
    {VV_NAME("folddashes",	 VAR_STRING), VV_RO_SBX},
    {VV_NAME("foldlevel",	 VAR_NUMBER), VV_RO_SBX},
    {VV_NAME("progname",	 VAR_STRING), VV_RO},
    {VV_NAME("servername",	 VAR_STRING), VV_RO},
    {VV_NAME("dying",		 VAR_NUMBER), VV_RO},
    {VV_NAME("exception",	 VAR_STRING), VV_RO},
    {VV_NAME("throwpoint",	 VAR_STRING), VV_RO},
    {VV_NAME("register",	 VAR_STRING), VV_RO},
    {VV_NAME("cmdbang",		 VAR_NUMBER), VV_RO},
    {VV_NAME("insertmode",	 VAR_STRING), VV_RO},
    {VV_NAME("val",		 VAR_UNKNOWN), VV_RO},
    {VV_NAME("key",		 VAR_UNKNOWN), VV_RO},
    {VV_NAME("profiling",	 VAR_NUMBER), VV_RO},
    {VV_NAME("fcs_reason",	 VAR_STRING), VV_RO},
    {VV_NAME("fcs_choice",	 VAR_STRING), 0},
    {VV_NAME("beval_bufnr",	 VAR_NUMBER), VV_RO},
    {VV_NAME("beval_winnr",	 VAR_NUMBER), VV_RO},
    {VV_NAME("beval_winid",	 VAR_NUMBER), VV_RO},
    {VV_NAME("beval_lnum",	 VAR_NUMBER), VV_RO},
    {VV_NAME("beval_col",	 VAR_NUMBER), VV_RO},
    {VV_NAME("beval_text",	 VAR_STRING), VV_RO},
    {VV_NAME("scrollstart",	 VAR_STRING), 0},
    {VV_NAME("swapname",	 VAR_STRING), VV_RO},
    {VV_NAME("swapchoice",	 VAR_STRING), 0},
    {VV_NAME("swapcommand",	 VAR_STRING), VV_RO},
    {VV_NAME("char",		 VAR_STRING), 0},
    {VV_NAME("mouse_win",	 VAR_NUMBER), 0},
    {VV_NAME("mouse_winid",	 VAR_NUMBER), 0},
    {VV_NAME("mouse_lnum",	 VAR_NUMBER), 0},
    {VV_NAME("mouse_col",	 VAR_NUMBER), 0},
    {VV_NAME("operator",	 VAR_STRING), VV_RO},
    {VV_NAME("searchforward",	 VAR_NUMBER), 0},
    {VV_NAME("hlsearch",	 VAR_NUMBER), 0},
    {VV_NAME("oldfiles",	 VAR_LIST), 0},
    {VV_NAME("windowid",	 VAR_NUMBER), VV_RO},
    {VV_NAME("progpath",	 VAR_STRING), VV_RO},
    {VV_NAME("completed_item",	 VAR_DICT), VV_RO},
    {VV_NAME("option_new",	 VAR_STRING), VV_RO},
    {VV_NAME("option_old",	 VAR_STRING), VV_RO},
    {VV_NAME("option_type",	 VAR_STRING), VV_RO},
    {VV_NAME("errors",		 VAR_LIST), 0},
    {VV_NAME("false",		 VAR_SPECIAL), VV_RO},
    {VV_NAME("true",		 VAR_SPECIAL), VV_RO},
    {VV_NAME("null",		 VAR_SPECIAL), VV_RO},
    {VV_NAME("none",		 VAR_SPECIAL), VV_RO},
    {VV_NAME("vim_did_enter",	 VAR_NUMBER), VV_RO},
    {VV_NAME("testing",		 VAR_NUMBER), 0},
    {VV_NAME("t_number",	 VAR_NUMBER), VV_RO},
    {VV_NAME("t_string",	 VAR_NUMBER), VV_RO},
    {VV_NAME("t_func",		 VAR_NUMBER), VV_RO},
    {VV_NAME("t_list",		 VAR_NUMBER), VV_RO},
    {VV_NAME("t_dict",		 VAR_NUMBER), VV_RO},
    {VV_NAME("t_float",		 VAR_NUMBER), VV_RO},
    {VV_NAME("t_bool",		 VAR_NUMBER), VV_RO},
    {VV_NAME("t_none",		 VAR_NUMBER), VV_RO},
    {VV_NAME("t_job",		 VAR_NUMBER), VV_RO},
    {VV_NAME("t_channel",	 VAR_NUMBER), VV_RO},
    {VV_NAME("termrgbresp",	 VAR_STRING), VV_RO},
    {VV_NAME("termu7resp",	 VAR_STRING), VV_RO},
    {VV_NAME("termstyleresp",	VAR_STRING), VV_RO},
    {VV_NAME("termblinkresp",	VAR_STRING), VV_RO},
};

/* shorthand */
#define vv_type		vv_di.di_tv.v_type
#define vv_nr		vv_di.di_tv.vval.v_number
#define vv_float	vv_di.di_tv.vval.v_float
#define vv_str		vv_di.di_tv.vval.v_string
#define vv_list		vv_di.di_tv.vval.v_list
#define vv_dict		vv_di.di_tv.vval.v_dict
#define vv_tv		vv_di.di_tv

static dictitem_T	vimvars_var;		/* variable used for v: */
#define vimvarht  vimvardict.dv_hashtab

static int ex_let_vars(char_u *arg, typval_T *tv, int copy, int semicolon, int var_count, char_u *nextchars);
static char_u *skip_var_list(char_u *arg, int *var_count, int *semicolon);
static char_u *skip_var_one(char_u *arg);
static void list_glob_vars(int *first);
static void list_buf_vars(int *first);
static void list_win_vars(int *first);
static void list_tab_vars(int *first);
static void list_vim_vars(int *first);
static void list_script_vars(int *first);
static char_u *list_arg_vars(exarg_T *eap, char_u *arg, int *first);
static char_u *ex_let_one(char_u *arg, typval_T *tv, int copy, char_u *endchars, char_u *op);
static void set_var_lval(lval_T *lp, char_u *endp, typval_T *rettv, int copy, char_u *op);
static int tv_op(typval_T *tv1, typval_T *tv2, char_u  *op);
static void ex_unletlock(exarg_T *eap, char_u *argstart, int deep);
static int do_unlet_var(lval_T *lp, char_u *name_end, int forceit);
static int do_lock_var(lval_T *lp, char_u *name_end, int deep, int lock);
static void item_lock(typval_T *tv, int deep, int lock);

static int eval2(char_u **arg, typval_T *rettv, int evaluate);
static int eval3(char_u **arg, typval_T *rettv, int evaluate);
static int eval4(char_u **arg, typval_T *rettv, int evaluate);
static int eval5(char_u **arg, typval_T *rettv, int evaluate);
static int eval6(char_u **arg, typval_T *rettv, int evaluate, int want_string);
static int eval7(char_u **arg, typval_T *rettv, int evaluate, int want_string);

static int eval_index(char_u **arg, typval_T *rettv, int evaluate, int verbose);
static int get_string_tv(char_u **arg, typval_T *rettv, int evaluate);
static int get_lit_string_tv(char_u **arg, typval_T *rettv, int evaluate);
static int free_unref_items(int copyID);
static int get_env_tv(char_u **arg, typval_T *rettv, int evaluate);
static int get_env_len(char_u **arg);
static char_u * make_expanded_name(char_u *in_start, char_u *expr_start, char_u *expr_end, char_u *in_end);
static void check_vars(char_u *name, int len);
static typval_T *alloc_string_tv(char_u *string);
static void delete_var(hashtab_T *ht, hashitem_T *hi);
static void list_one_var(dictitem_T *v, char_u *prefix, int *first);
static void list_one_var_a(char_u *prefix, char_u *name, int type, char_u *string, int *first);
static char_u *find_option_end(char_u **arg, int *opt_flags);

/* for VIM_VERSION_ defines */
#include "version.h"


#if defined(EBCDIC) || defined(PROTO)
/*
 * Compare struct fst by function name.
 */
    static int
compare_func_name(const void *s1, const void *s2)
{
    struct fst *p1 = (struct fst *)s1;
    struct fst *p2 = (struct fst *)s2;

    return STRCMP(p1->f_name, p2->f_name);
}

/*
 * Sort the function table by function name.
 * The sorting of the table above is ASCII dependant.
 * On machines using EBCDIC we have to sort it.
 */
    static void
sortFunctions(void)
{
    int		funcCnt = (int)(sizeof(functions) / sizeof(struct fst)) - 1;

    qsort(functions, (size_t)funcCnt, sizeof(struct fst), compare_func_name);
}
#endif


/*
 * Initialize the global and v: variables.
 */
    void
eval_init(void)
{
    int		    i;
    struct vimvar   *p;

    init_var_dict(&globvardict, &globvars_var, VAR_DEF_SCOPE);
    init_var_dict(&vimvardict, &vimvars_var, VAR_SCOPE);
    vimvardict.dv_lock = VAR_FIXED;
    hash_init(&compat_hashtab);
    func_init();

    for (i = 0; i < VV_LEN; ++i)
    {
	p = &vimvars[i];
	if (STRLEN(p->vv_name) > 16)
	{
	    IEMSG("INTERNAL: name too long, increase size of dictitem16_T");
	    getout(1);
	}
	STRCPY(p->vv_di.di_key, p->vv_name);
	if (p->vv_flags & VV_RO)
	    p->vv_di.di_flags = DI_FLAGS_RO | DI_FLAGS_FIX;
	else if (p->vv_flags & VV_RO_SBX)
	    p->vv_di.di_flags = DI_FLAGS_RO_SBX | DI_FLAGS_FIX;
	else
	    p->vv_di.di_flags = DI_FLAGS_FIX;

	/* add to v: scope dict, unless the value is not always available */
	if (p->vv_type != VAR_UNKNOWN)
	    hash_add(&vimvarht, p->vv_di.di_key);
	if (p->vv_flags & VV_COMPAT)
	    /* add to compat scope dict */
	    hash_add(&compat_hashtab, p->vv_di.di_key);
    }
    vimvars[VV_VERSION].vv_nr = VIM_VERSION_100;

    set_vim_var_nr(VV_SEARCHFORWARD, 1L);
    set_vim_var_nr(VV_HLSEARCH, 1L);
    set_vim_var_dict(VV_COMPLETED_ITEM, dict_alloc());
    set_vim_var_list(VV_ERRORS, list_alloc());

    set_vim_var_nr(VV_FALSE, VVAL_FALSE);
    set_vim_var_nr(VV_TRUE, VVAL_TRUE);
    set_vim_var_nr(VV_NONE, VVAL_NONE);
    set_vim_var_nr(VV_NULL, VVAL_NULL);

    set_vim_var_nr(VV_TYPE_NUMBER,  VAR_TYPE_NUMBER);
    set_vim_var_nr(VV_TYPE_STRING,  VAR_TYPE_STRING);
    set_vim_var_nr(VV_TYPE_FUNC,    VAR_TYPE_FUNC);
    set_vim_var_nr(VV_TYPE_LIST,    VAR_TYPE_LIST);
    set_vim_var_nr(VV_TYPE_DICT,    VAR_TYPE_DICT);
    set_vim_var_nr(VV_TYPE_FLOAT,   VAR_TYPE_FLOAT);
    set_vim_var_nr(VV_TYPE_BOOL,    VAR_TYPE_BOOL);
    set_vim_var_nr(VV_TYPE_NONE,    VAR_TYPE_NONE);
    set_vim_var_nr(VV_TYPE_JOB,     VAR_TYPE_JOB);
    set_vim_var_nr(VV_TYPE_CHANNEL, VAR_TYPE_CHANNEL);

    set_reg_var(0);  /* default for v:register is not 0 but '"' */

#ifdef EBCDIC
    /*
     * Sort the function table, to enable binary search.
     */
    sortFunctions();
#endif
}

#if defined(EXITFREE) || defined(PROTO)
    void
eval_clear(void)
{
    int		    i;
    struct vimvar   *p;

    for (i = 0; i < VV_LEN; ++i)
    {
	p = &vimvars[i];
	if (p->vv_di.di_tv.v_type == VAR_STRING)
	{
	    vim_free(p->vv_str);
	    p->vv_str = NULL;
	}
	else if (p->vv_di.di_tv.v_type == VAR_LIST)
	{
	    list_unref(p->vv_list);
	    p->vv_list = NULL;
	}
    }
    hash_clear(&vimvarht);
    hash_init(&vimvarht);  /* garbage_collect() will access it */
    hash_clear(&compat_hashtab);

    free_scriptnames();
# if defined(FEAT_CMDL_COMPL)
    free_locales();
# endif

    /* global variables */
    vars_clear(&globvarht);

    /* autoloaded script names */
    ga_clear_strings(&ga_loaded);

    /* Script-local variables. First clear all the variables and in a second
     * loop free the scriptvar_T, because a variable in one script might hold
     * a reference to the whole scope of another script. */
    for (i = 1; i <= ga_scripts.ga_len; ++i)
	vars_clear(&SCRIPT_VARS(i));
    for (i = 1; i <= ga_scripts.ga_len; ++i)
	vim_free(SCRIPT_SV(i));
    ga_clear(&ga_scripts);

    /* unreferenced lists and dicts */
    (void)garbage_collect(FALSE);

    /* functions */
    free_all_functions();
}
#endif


/*
 * Set an internal variable to a string value. Creates the variable if it does
 * not already exist.
 */
    void
set_internal_string_var(char_u *name, char_u *value)
{
    char_u	*val;
    typval_T	*tvp;

    val = vim_strsave(value);
    if (val != NULL)
    {
	tvp = alloc_string_tv(val);
	if (tvp != NULL)
	{
	    set_var(name, tvp, FALSE);
	    free_tv(tvp);
	}
    }
}

static lval_T	*redir_lval = NULL;
#define EVALCMD_BUSY (redir_lval == (lval_T *)&redir_lval)
static garray_T redir_ga;	/* only valid when redir_lval is not NULL */
static char_u	*redir_endp = NULL;
static char_u	*redir_varname = NULL;

/*
 * Start recording command output to a variable
 * When "append" is TRUE append to an existing variable.
 * Returns OK if successfully completed the setup.  FAIL otherwise.
 */
    int
var_redir_start(char_u *name, int append)
{
    int		save_emsg;
    int		err;
    typval_T	tv;

    /* Catch a bad name early. */
    if (!eval_isnamec1(*name))
    {
	EMSG(_(e_invarg));
	return FAIL;
    }

    /* Make a copy of the name, it is used in redir_lval until redir ends. */
    redir_varname = vim_strsave(name);
    if (redir_varname == NULL)
	return FAIL;

    redir_lval = (lval_T *)alloc_clear((unsigned)sizeof(lval_T));
    if (redir_lval == NULL)
    {
	var_redir_stop();
	return FAIL;
    }

    /* The output is stored in growarray "redir_ga" until redirection ends. */
    ga_init2(&redir_ga, (int)sizeof(char), 500);

    /* Parse the variable name (can be a dict or list entry). */
    redir_endp = get_lval(redir_varname, NULL, redir_lval, FALSE, FALSE, 0,
							     FNE_CHECK_START);
    if (redir_endp == NULL || redir_lval->ll_name == NULL || *redir_endp != NUL)
    {
	clear_lval(redir_lval);
	if (redir_endp != NULL && *redir_endp != NUL)
	    /* Trailing characters are present after the variable name */
	    EMSG(_(e_trailing));
	else
	    EMSG(_(e_invarg));
	redir_endp = NULL;  /* don't store a value, only cleanup */
	var_redir_stop();
	return FAIL;
    }

    /* check if we can write to the variable: set it to or append an empty
     * string */
    save_emsg = did_emsg;
    did_emsg = FALSE;
    tv.v_type = VAR_STRING;
    tv.vval.v_string = (char_u *)"";
    if (append)
	set_var_lval(redir_lval, redir_endp, &tv, TRUE, (char_u *)".");
    else
	set_var_lval(redir_lval, redir_endp, &tv, TRUE, (char_u *)"=");
    clear_lval(redir_lval);
    err = did_emsg;
    did_emsg |= save_emsg;
    if (err)
    {
	redir_endp = NULL;  /* don't store a value, only cleanup */
	var_redir_stop();
	return FAIL;
    }

    return OK;
}

/*
 * Append "value[value_len]" to the variable set by var_redir_start().
 * The actual appending is postponed until redirection ends, because the value
 * appended may in fact be the string we write to, changing it may cause freed
 * memory to be used:
 *   :redir => foo
 *   :let foo
 *   :redir END
 */
    void
var_redir_str(char_u *value, int value_len)
{
    int		len;

    if (redir_lval == NULL)
	return;

    if (value_len == -1)
	len = (int)STRLEN(value);	/* Append the entire string */
    else
	len = value_len;		/* Append only "value_len" characters */

    if (ga_grow(&redir_ga, len) == OK)
    {
	mch_memmove((char *)redir_ga.ga_data + redir_ga.ga_len, value, len);
	redir_ga.ga_len += len;
    }
    else
	var_redir_stop();
}

/*
 * Stop redirecting command output to a variable.
 * Frees the allocated memory.
 */
    void
var_redir_stop(void)
{
    typval_T	tv;

    if (EVALCMD_BUSY)
    {
	redir_lval = NULL;
	return;
    }

    if (redir_lval != NULL)
    {
	/* If there was no error: assign the text to the variable. */
	if (redir_endp != NULL)
	{
	    ga_append(&redir_ga, NUL);  /* Append the trailing NUL. */
	    tv.v_type = VAR_STRING;
	    tv.vval.v_string = redir_ga.ga_data;
	    /* Call get_lval() again, if it's inside a Dict or List it may
	     * have changed. */
	    redir_endp = get_lval(redir_varname, NULL, redir_lval,
					FALSE, FALSE, 0, FNE_CHECK_START);
	    if (redir_endp != NULL && redir_lval->ll_name != NULL)
		set_var_lval(redir_lval, redir_endp, &tv, FALSE, (char_u *)".");
	    clear_lval(redir_lval);
	}

	/* free the collected output */
	vim_free(redir_ga.ga_data);
	redir_ga.ga_data = NULL;

	vim_free(redir_lval);
	redir_lval = NULL;
    }
    vim_free(redir_varname);
    redir_varname = NULL;
}

# if defined(FEAT_MBYTE) || defined(PROTO)
    int
eval_charconvert(
    char_u	*enc_from,
    char_u	*enc_to,
    char_u	*fname_from,
    char_u	*fname_to)
{
    int		err = FALSE;

    set_vim_var_string(VV_CC_FROM, enc_from, -1);
    set_vim_var_string(VV_CC_TO, enc_to, -1);
    set_vim_var_string(VV_FNAME_IN, fname_from, -1);
    set_vim_var_string(VV_FNAME_OUT, fname_to, -1);
    if (eval_to_bool(p_ccv, &err, NULL, FALSE))
	err = TRUE;
    set_vim_var_string(VV_CC_FROM, NULL, -1);
    set_vim_var_string(VV_CC_TO, NULL, -1);
    set_vim_var_string(VV_FNAME_IN, NULL, -1);
    set_vim_var_string(VV_FNAME_OUT, NULL, -1);

    if (err)
	return FAIL;
    return OK;
}
# endif

# if defined(FEAT_POSTSCRIPT) || defined(PROTO)
    int
eval_printexpr(char_u *fname, char_u *args)
{
    int		err = FALSE;

    set_vim_var_string(VV_FNAME_IN, fname, -1);
    set_vim_var_string(VV_CMDARG, args, -1);
    if (eval_to_bool(p_pexpr, &err, NULL, FALSE))
	err = TRUE;
    set_vim_var_string(VV_FNAME_IN, NULL, -1);
    set_vim_var_string(VV_CMDARG, NULL, -1);

    if (err)
    {
	mch_remove(fname);
	return FAIL;
    }
    return OK;
}
# endif

# if defined(FEAT_DIFF) || defined(PROTO)
    void
eval_diff(
    char_u	*origfile,
    char_u	*newfile,
    char_u	*outfile)
{
    int		err = FALSE;

    set_vim_var_string(VV_FNAME_IN, origfile, -1);
    set_vim_var_string(VV_FNAME_NEW, newfile, -1);
    set_vim_var_string(VV_FNAME_OUT, outfile, -1);
    (void)eval_to_bool(p_dex, &err, NULL, FALSE);
    set_vim_var_string(VV_FNAME_IN, NULL, -1);
    set_vim_var_string(VV_FNAME_NEW, NULL, -1);
    set_vim_var_string(VV_FNAME_OUT, NULL, -1);
}

    void
eval_patch(
    char_u	*origfile,
    char_u	*difffile,
    char_u	*outfile)
{
    int		err;

    set_vim_var_string(VV_FNAME_IN, origfile, -1);
    set_vim_var_string(VV_FNAME_DIFF, difffile, -1);
    set_vim_var_string(VV_FNAME_OUT, outfile, -1);
    (void)eval_to_bool(p_pex, &err, NULL, FALSE);
    set_vim_var_string(VV_FNAME_IN, NULL, -1);
    set_vim_var_string(VV_FNAME_DIFF, NULL, -1);
    set_vim_var_string(VV_FNAME_OUT, NULL, -1);
}
# endif

/*
 * Top level evaluation function, returning a boolean.
 * Sets "error" to TRUE if there was an error.
 * Return TRUE or FALSE.
 */
    int
eval_to_bool(
    char_u	*arg,
    int		*error,
    char_u	**nextcmd,
    int		skip)	    /* only parse, don't execute */
{
    typval_T	tv;
    varnumber_T	retval = FALSE;

    if (skip)
	++emsg_skip;
    if (eval0(arg, &tv, nextcmd, !skip) == FAIL)
	*error = TRUE;
    else
    {
	*error = FALSE;
	if (!skip)
	{
	    retval = (get_tv_number_chk(&tv, error) != 0);
	    clear_tv(&tv);
	}
    }
    if (skip)
	--emsg_skip;

    return (int)retval;
}

/*
 * Top level evaluation function, returning a string.  If "skip" is TRUE,
 * only parsing to "nextcmd" is done, without reporting errors.  Return
 * pointer to allocated memory, or NULL for failure or when "skip" is TRUE.
 */
    char_u *
eval_to_string_skip(
    char_u	*arg,
    char_u	**nextcmd,
    int		skip)	    /* only parse, don't execute */
{
    typval_T	tv;
    char_u	*retval;

    if (skip)
	++emsg_skip;
    if (eval0(arg, &tv, nextcmd, !skip) == FAIL || skip)
	retval = NULL;
    else
    {
	retval = vim_strsave(get_tv_string(&tv));
	clear_tv(&tv);
    }
    if (skip)
	--emsg_skip;

    return retval;
}

/*
 * Skip over an expression at "*pp".
 * Return FAIL for an error, OK otherwise.
 */
    int
skip_expr(char_u **pp)
{
    typval_T	rettv;

    *pp = skipwhite(*pp);
    return eval1(pp, &rettv, FALSE);
}

/*
 * Top level evaluation function, returning a string.
 * When "convert" is TRUE convert a List into a sequence of lines and convert
 * a Float to a String.
 * Return pointer to allocated memory, or NULL for failure.
 */
    char_u *
eval_to_string(
    char_u	*arg,
    char_u	**nextcmd,
    int		convert)
{
    typval_T	tv;
    char_u	*retval;
    garray_T	ga;
#ifdef FEAT_FLOAT
    char_u	numbuf[NUMBUFLEN];
#endif

    if (eval0(arg, &tv, nextcmd, TRUE) == FAIL)
	retval = NULL;
    else
    {
	if (convert && tv.v_type == VAR_LIST)
	{
	    ga_init2(&ga, (int)sizeof(char), 80);
	    if (tv.vval.v_list != NULL)
	    {
		list_join(&ga, tv.vval.v_list, (char_u *)"\n", TRUE, FALSE, 0);
		if (tv.vval.v_list->lv_len > 0)
		    ga_append(&ga, NL);
	    }
	    ga_append(&ga, NUL);
	    retval = (char_u *)ga.ga_data;
	}
#ifdef FEAT_FLOAT
	else if (convert && tv.v_type == VAR_FLOAT)
	{
	    vim_snprintf((char *)numbuf, NUMBUFLEN, "%g", tv.vval.v_float);
	    retval = vim_strsave(numbuf);
	}
#endif
	else
	    retval = vim_strsave(get_tv_string(&tv));
	clear_tv(&tv);
    }

    return retval;
}

/*
 * Call eval_to_string() without using current local variables and using
 * textlock.  When "use_sandbox" is TRUE use the sandbox.
 */
    char_u *
eval_to_string_safe(
    char_u	*arg,
    char_u	**nextcmd,
    int		use_sandbox)
{
    char_u	*retval;
    void	*save_funccalp;

    save_funccalp = save_funccal();
    if (use_sandbox)
	++sandbox;
    ++textlock;
    retval = eval_to_string(arg, nextcmd, FALSE);
    if (use_sandbox)
	--sandbox;
    --textlock;
    restore_funccal(save_funccalp);
    return retval;
}

/*
 * Top level evaluation function, returning a number.
 * Evaluates "expr" silently.
 * Returns -1 for an error.
 */
    varnumber_T
eval_to_number(char_u *expr)
{
    typval_T	rettv;
    varnumber_T	retval;
    char_u	*p = skipwhite(expr);

    ++emsg_off;

    if (eval1(&p, &rettv, TRUE) == FAIL)
	retval = -1;
    else
    {
	retval = get_tv_number_chk(&rettv, NULL);
	clear_tv(&rettv);
    }
    --emsg_off;

    return retval;
}

/*
 * Prepare v: variable "idx" to be used.
 * Save the current typeval in "save_tv".
 * When not used yet add the variable to the v: hashtable.
 */
    static void
prepare_vimvar(int idx, typval_T *save_tv)
{
    *save_tv = vimvars[idx].vv_tv;
    if (vimvars[idx].vv_type == VAR_UNKNOWN)
	hash_add(&vimvarht, vimvars[idx].vv_di.di_key);
}

/*
 * Restore v: variable "idx" to typeval "save_tv".
 * When no longer defined, remove the variable from the v: hashtable.
 */
    static void
restore_vimvar(int idx, typval_T *save_tv)
{
    hashitem_T	*hi;

    vimvars[idx].vv_tv = *save_tv;
    if (vimvars[idx].vv_type == VAR_UNKNOWN)
    {
	hi = hash_find(&vimvarht, vimvars[idx].vv_di.di_key);
	if (HASHITEM_EMPTY(hi))
	    internal_error("restore_vimvar()");
	else
	    hash_remove(&vimvarht, hi);
    }
}

#if defined(FEAT_SPELL) || defined(PROTO)
/*
 * Evaluate an expression to a list with suggestions.
 * For the "expr:" part of 'spellsuggest'.
 * Returns NULL when there is an error.
 */
    list_T *
eval_spell_expr(char_u *badword, char_u *expr)
{
    typval_T	save_val;
    typval_T	rettv;
    list_T	*list = NULL;
    char_u	*p = skipwhite(expr);

    /* Set "v:val" to the bad word. */
    prepare_vimvar(VV_VAL, &save_val);
    vimvars[VV_VAL].vv_type = VAR_STRING;
    vimvars[VV_VAL].vv_str = badword;
    if (p_verbose == 0)
	++emsg_off;

    if (eval1(&p, &rettv, TRUE) == OK)
    {
	if (rettv.v_type != VAR_LIST)
	    clear_tv(&rettv);
	else
	    list = rettv.vval.v_list;
    }

    if (p_verbose == 0)
	--emsg_off;
    restore_vimvar(VV_VAL, &save_val);

    return list;
}

/*
 * "list" is supposed to contain two items: a word and a number.  Return the
 * word in "pp" and the number as the return value.
 * Return -1 if anything isn't right.
 * Used to get the good word and score from the eval_spell_expr() result.
 */
    int
get_spellword(list_T *list, char_u **pp)
{
    listitem_T	*li;

    li = list->lv_first;
    if (li == NULL)
	return -1;
    *pp = get_tv_string(&li->li_tv);

    li = li->li_next;
    if (li == NULL)
	return -1;
    return (int)get_tv_number(&li->li_tv);
}
#endif

/*
 * Top level evaluation function.
 * Returns an allocated typval_T with the result.
 * Returns NULL when there is an error.
 */
    typval_T *
eval_expr(char_u *arg, char_u **nextcmd)
{
    typval_T	*tv;

    tv = (typval_T *)alloc(sizeof(typval_T));
    if (tv != NULL && eval0(arg, tv, nextcmd, TRUE) == FAIL)
    {
	vim_free(tv);
	tv = NULL;
    }

    return tv;
}


/*
 * Call some Vim script function and return the result in "*rettv".
 * Uses argv[argc] for the function arguments.  Only Number and String
 * arguments are currently supported.
 * Returns OK or FAIL.
 */
    int
call_vim_function(
    char_u      *func,
    int		argc,
    char_u      **argv,
    int		safe,		/* use the sandbox */
    int		str_arg_only,	/* all arguments are strings */
    typval_T	*rettv)
{
    typval_T	*argvars;
    varnumber_T	n;
    int		len;
    int		i;
    int		doesrange;
    void	*save_funccalp = NULL;
    int		ret;

    argvars = (typval_T *)alloc((unsigned)((argc + 1) * sizeof(typval_T)));
    if (argvars == NULL)
	return FAIL;

    for (i = 0; i < argc; i++)
    {
	/* Pass a NULL or empty argument as an empty string */
	if (argv[i] == NULL || *argv[i] == NUL)
	{
	    argvars[i].v_type = VAR_STRING;
	    argvars[i].vval.v_string = (char_u *)"";
	    continue;
	}

	if (str_arg_only)
	    len = 0;
	else
	    /* Recognize a number argument, the others must be strings. */
	    vim_str2nr(argv[i], NULL, &len, STR2NR_ALL, &n, NULL, 0);
	if (len != 0 && len == (int)STRLEN(argv[i]))
	{
	    argvars[i].v_type = VAR_NUMBER;
	    argvars[i].vval.v_number = n;
	}
	else
	{
	    argvars[i].v_type = VAR_STRING;
	    argvars[i].vval.v_string = argv[i];
	}
    }

    if (safe)
    {
	save_funccalp = save_funccal();
	++sandbox;
    }

    rettv->v_type = VAR_UNKNOWN;		/* clear_tv() uses this */
    ret = call_func(func, (int)STRLEN(func), rettv, argc, argvars, NULL,
		    curwin->w_cursor.lnum, curwin->w_cursor.lnum,
		    &doesrange, TRUE, NULL, NULL);
    if (safe)
    {
	--sandbox;
	restore_funccal(save_funccalp);
    }
    vim_free(argvars);

    if (ret == FAIL)
	clear_tv(rettv);

    return ret;
}

/*
 * Call Vim script function "func" and return the result as a number.
 * Returns -1 when calling the function fails.
 * Uses argv[argc] for the function arguments.
 */
    varnumber_T
call_func_retnr(
    char_u      *func,
    int		argc,
    char_u      **argv,
    int		safe)		/* use the sandbox */
{
    typval_T	rettv;
    varnumber_T	retval;

    /* All arguments are passed as strings, no conversion to number. */
    if (call_vim_function(func, argc, argv, safe, TRUE, &rettv) == FAIL)
	return -1;

    retval = get_tv_number_chk(&rettv, NULL);
    clear_tv(&rettv);
    return retval;
}

#if (defined(FEAT_USR_CMDS) && defined(FEAT_CMDL_COMPL)) \
	|| defined(FEAT_COMPL_FUNC) || defined(PROTO)

# if (defined(FEAT_USR_CMDS) && defined(FEAT_CMDL_COMPL)) || defined(PROTO)
/*
 * Call Vim script function "func" and return the result as a string.
 * Returns NULL when calling the function fails.
 * Uses argv[argc] for the function arguments.
 */
    void *
call_func_retstr(
    char_u      *func,
    int		argc,
    char_u      **argv,
    int		safe)		/* use the sandbox */
{
    typval_T	rettv;
    char_u	*retval;

    /* All arguments are passed as strings, no conversion to number. */
    if (call_vim_function(func, argc, argv, safe, TRUE, &rettv) == FAIL)
	return NULL;

    retval = vim_strsave(get_tv_string(&rettv));
    clear_tv(&rettv);
    return retval;
}
# endif

/*
 * Call Vim script function "func" and return the result as a List.
 * Uses argv[argc] for the function arguments.
 * Returns NULL when there is something wrong.
 */
    void *
call_func_retlist(
    char_u      *func,
    int		argc,
    char_u      **argv,
    int		safe)		/* use the sandbox */
{
    typval_T	rettv;

    /* All arguments are passed as strings, no conversion to number. */
    if (call_vim_function(func, argc, argv, safe, TRUE, &rettv) == FAIL)
	return NULL;

    if (rettv.v_type != VAR_LIST)
    {
	clear_tv(&rettv);
	return NULL;
    }

    return rettv.vval.v_list;
}
#endif


#ifdef FEAT_FOLDING
/*
 * Evaluate 'foldexpr'.  Returns the foldlevel, and any character preceding
 * it in "*cp".  Doesn't give error messages.
 */
    int
eval_foldexpr(char_u *arg, int *cp)
{
    typval_T	tv;
    varnumber_T	retval;
    char_u	*s;
    int		use_sandbox = was_set_insecurely((char_u *)"foldexpr",
								   OPT_LOCAL);

    ++emsg_off;
    if (use_sandbox)
	++sandbox;
    ++textlock;
    *cp = NUL;
    if (eval0(arg, &tv, NULL, TRUE) == FAIL)
	retval = 0;
    else
    {
	/* If the result is a number, just return the number. */
	if (tv.v_type == VAR_NUMBER)
	    retval = tv.vval.v_number;
	else if (tv.v_type != VAR_STRING || tv.vval.v_string == NULL)
	    retval = 0;
	else
	{
	    /* If the result is a string, check if there is a non-digit before
	     * the number. */
	    s = tv.vval.v_string;
	    if (!VIM_ISDIGIT(*s) && *s != '-')
		*cp = *s++;
	    retval = atol((char *)s);
	}
	clear_tv(&tv);
    }
    --emsg_off;
    if (use_sandbox)
	--sandbox;
    --textlock;

    return (int)retval;
}
#endif

/*
 * ":let"			list all variable values
 * ":let var1 var2"		list variable values
 * ":let var = expr"		assignment command.
 * ":let var += expr"		assignment command.
 * ":let var -= expr"		assignment command.
 * ":let var .= expr"		assignment command.
 * ":let [var1, var2] = expr"	unpack list.
 */
    void
ex_let(exarg_T *eap)
{
    char_u	*arg = eap->arg;
    char_u	*expr = NULL;
    typval_T	rettv;
    int		i;
    int		var_count = 0;
    int		semicolon = 0;
    char_u	op[2];
    char_u	*argend;
    int		first = TRUE;

    argend = skip_var_list(arg, &var_count, &semicolon);
    if (argend == NULL)
	return;
    if (argend > arg && argend[-1] == '.')  /* for var.='str' */
	--argend;
    expr = skipwhite(argend);
    if (*expr != '=' && !(vim_strchr((char_u *)"+-.", *expr) != NULL
			  && expr[1] == '='))
    {
	/*
	 * ":let" without "=": list variables
	 */
	if (*arg == '[')
	    EMSG(_(e_invarg));
	else if (!ends_excmd(*arg))
	    /* ":let var1 var2" */
	    arg = list_arg_vars(eap, arg, &first);
	else if (!eap->skip)
	{
	    /* ":let" */
	    list_glob_vars(&first);
	    list_buf_vars(&first);
	    list_win_vars(&first);
	    list_tab_vars(&first);
	    list_script_vars(&first);
	    list_func_vars(&first);
	    list_vim_vars(&first);
	}
	eap->nextcmd = check_nextcmd(arg);
    }
    else
    {
	op[0] = '=';
	op[1] = NUL;
	if (*expr != '=')
	{
	    if (vim_strchr((char_u *)"+-.", *expr) != NULL)
		op[0] = *expr;   /* +=, -= or .= */
	    expr = skipwhite(expr + 2);
	}
	else
	    expr = skipwhite(expr + 1);

	if (eap->skip)
	    ++emsg_skip;
	i = eval0(expr, &rettv, &eap->nextcmd, !eap->skip);
	if (eap->skip)
	{
	    if (i != FAIL)
		clear_tv(&rettv);
	    --emsg_skip;
	}
	else if (i != FAIL)
	{
	    (void)ex_let_vars(eap->arg, &rettv, FALSE, semicolon, var_count,
									  op);
	    clear_tv(&rettv);
	}
    }
}

/*
 * Assign the typevalue "tv" to the variable or variables at "arg_start".
 * Handles both "var" with any type and "[var, var; var]" with a list type.
 * When "nextchars" is not NULL it points to a string with characters that
 * must appear after the variable(s).  Use "+", "-" or "." for add, subtract
 * or concatenate.
 * Returns OK or FAIL;
 */
    static int
ex_let_vars(
    char_u	*arg_start,
    typval_T	*tv,
    int		copy,		/* copy values from "tv", don't move */
    int		semicolon,	/* from skip_var_list() */
    int		var_count,	/* from skip_var_list() */
    char_u	*nextchars)
{
    char_u	*arg = arg_start;
    list_T	*l;
    int		i;
    listitem_T	*item;
    typval_T	ltv;

    if (*arg != '[')
    {
	/*
	 * ":let var = expr" or ":for var in list"
	 */
	if (ex_let_one(arg, tv, copy, nextchars, nextchars) == NULL)
	    return FAIL;
	return OK;
    }

    /*
     * ":let [v1, v2] = list" or ":for [v1, v2] in listlist"
     */
    if (tv->v_type != VAR_LIST || (l = tv->vval.v_list) == NULL)
    {
	EMSG(_(e_listreq));
	return FAIL;
    }

    i = list_len(l);
    if (semicolon == 0 && var_count < i)
    {
	EMSG(_("E687: Less targets than List items"));
	return FAIL;
    }
    if (var_count - semicolon > i)
    {
	EMSG(_("E688: More targets than List items"));
	return FAIL;
    }

    item = l->lv_first;
    while (*arg != ']')
    {
	arg = skipwhite(arg + 1);
	arg = ex_let_one(arg, &item->li_tv, TRUE, (char_u *)",;]", nextchars);
	item = item->li_next;
	if (arg == NULL)
	    return FAIL;

	arg = skipwhite(arg);
	if (*arg == ';')
	{
	    /* Put the rest of the list (may be empty) in the var after ';'.
	     * Create a new list for this. */
	    l = list_alloc();
	    if (l == NULL)
		return FAIL;
	    while (item != NULL)
	    {
		list_append_tv(l, &item->li_tv);
		item = item->li_next;
	    }

	    ltv.v_type = VAR_LIST;
	    ltv.v_lock = 0;
	    ltv.vval.v_list = l;
	    l->lv_refcount = 1;

	    arg = ex_let_one(skipwhite(arg + 1), &ltv, FALSE,
						    (char_u *)"]", nextchars);
	    clear_tv(&ltv);
	    if (arg == NULL)
		return FAIL;
	    break;
	}
	else if (*arg != ',' && *arg != ']')
	{
	    internal_error("ex_let_vars()");
	    return FAIL;
	}
    }

    return OK;
}

/*
 * Skip over assignable variable "var" or list of variables "[var, var]".
 * Used for ":let varvar = expr" and ":for varvar in expr".
 * For "[var, var]" increment "*var_count" for each variable.
 * for "[var, var; var]" set "semicolon".
 * Return NULL for an error.
 */
    static char_u *
skip_var_list(
    char_u	*arg,
    int		*var_count,
    int		*semicolon)
{
    char_u	*p, *s;

    if (*arg == '[')
    {
	/* "[var, var]": find the matching ']'. */
	p = arg;
	for (;;)
	{
	    p = skipwhite(p + 1);	/* skip whites after '[', ';' or ',' */
	    s = skip_var_one(p);
	    if (s == p)
	    {
		EMSG2(_(e_invarg2), p);
		return NULL;
	    }
	    ++*var_count;

	    p = skipwhite(s);
	    if (*p == ']')
		break;
	    else if (*p == ';')
	    {
		if (*semicolon == 1)
		{
		    EMSG(_("Double ; in list of variables"));
		    return NULL;
		}
		*semicolon = 1;
	    }
	    else if (*p != ',')
	    {
		EMSG2(_(e_invarg2), p);
		return NULL;
	    }
	}
	return p + 1;
    }
    else
	return skip_var_one(arg);
}

/*
 * Skip one (assignable) variable name, including @r, $VAR, &option, d.key,
 * l[idx].
 */
    static char_u *
skip_var_one(char_u *arg)
{
    if (*arg == '@' && arg[1] != NUL)
	return arg + 2;
    return find_name_end(*arg == '$' || *arg == '&' ? arg + 1 : arg,
				   NULL, NULL, FNE_INCL_BR | FNE_CHECK_START);
}

/*
 * List variables for hashtab "ht" with prefix "prefix".
 * If "empty" is TRUE also list NULL strings as empty strings.
 */
    void
list_hashtable_vars(
    hashtab_T	*ht,
    char_u	*prefix,
    int		empty,
    int		*first)
{
    hashitem_T	*hi;
    dictitem_T	*di;
    int		todo;

    todo = (int)ht->ht_used;
    for (hi = ht->ht_array; todo > 0 && !got_int; ++hi)
    {
	if (!HASHITEM_EMPTY(hi))
	{
	    --todo;
	    di = HI2DI(hi);
	    if (empty || di->di_tv.v_type != VAR_STRING
					   || di->di_tv.vval.v_string != NULL)
		list_one_var(di, prefix, first);
	}
    }
}

/*
 * List global variables.
 */
    static void
list_glob_vars(int *first)
{
    list_hashtable_vars(&globvarht, (char_u *)"", TRUE, first);
}

/*
 * List buffer variables.
 */
    static void
list_buf_vars(int *first)
{
    list_hashtable_vars(&curbuf->b_vars->dv_hashtab, (char_u *)"b:",
								 TRUE, first);
}

/*
 * List window variables.
 */
    static void
list_win_vars(int *first)
{
    list_hashtable_vars(&curwin->w_vars->dv_hashtab,
						 (char_u *)"w:", TRUE, first);
}

/*
 * List tab page variables.
 */
    static void
list_tab_vars(int *first)
{
    list_hashtable_vars(&curtab->tp_vars->dv_hashtab,
						 (char_u *)"t:", TRUE, first);
}

/*
 * List Vim variables.
 */
    static void
list_vim_vars(int *first)
{
    list_hashtable_vars(&vimvarht, (char_u *)"v:", FALSE, first);
}

/*
 * List script-local variables, if there is a script.
 */
    static void
list_script_vars(int *first)
{
    if (current_SID > 0 && current_SID <= ga_scripts.ga_len)
	list_hashtable_vars(&SCRIPT_VARS(current_SID),
						(char_u *)"s:", FALSE, first);
}

/*
 * List variables in "arg".
 */
    static char_u *
list_arg_vars(exarg_T *eap, char_u *arg, int *first)
{
    int		error = FALSE;
    int		len;
    char_u	*name;
    char_u	*name_start;
    char_u	*arg_subsc;
    char_u	*tofree;
    typval_T    tv;

    while (!ends_excmd(*arg) && !got_int)
    {
	if (error || eap->skip)
	{
	    arg = find_name_end(arg, NULL, NULL, FNE_INCL_BR | FNE_CHECK_START);
	    if (!VIM_ISWHITE(*arg) && !ends_excmd(*arg))
	    {
		emsg_severe = TRUE;
		EMSG(_(e_trailing));
		break;
	    }
	}
	else
	{
	    /* get_name_len() takes care of expanding curly braces */
	    name_start = name = arg;
	    len = get_name_len(&arg, &tofree, TRUE, TRUE);
	    if (len <= 0)
	    {
		/* This is mainly to keep test 49 working: when expanding
		 * curly braces fails overrule the exception error message. */
		if (len < 0 && !aborting())
		{
		    emsg_severe = TRUE;
		    EMSG2(_(e_invarg2), arg);
		    break;
		}
		error = TRUE;
	    }
	    else
	    {
		if (tofree != NULL)
		    name = tofree;
		if (get_var_tv(name, len, &tv, NULL, TRUE, FALSE) == FAIL)
		    error = TRUE;
		else
		{
		    /* handle d.key, l[idx], f(expr) */
		    arg_subsc = arg;
		    if (handle_subscript(&arg, &tv, TRUE, TRUE) == FAIL)
			error = TRUE;
		    else
		    {
			if (arg == arg_subsc && len == 2 && name[1] == ':')
			{
			    switch (*name)
			    {
				case 'g': list_glob_vars(first); break;
				case 'b': list_buf_vars(first); break;
				case 'w': list_win_vars(first); break;
				case 't': list_tab_vars(first); break;
				case 'v': list_vim_vars(first); break;
				case 's': list_script_vars(first); break;
				case 'l': list_func_vars(first); break;
				default:
					  EMSG2(_("E738: Can't list variables for %s"), name);
			    }
			}
			else
			{
			    char_u	numbuf[NUMBUFLEN];
			    char_u	*tf;
			    int		c;
			    char_u	*s;

			    s = echo_string(&tv, &tf, numbuf, 0);
			    c = *arg;
			    *arg = NUL;
			    list_one_var_a((char_u *)"",
				    arg == arg_subsc ? name : name_start,
				    tv.v_type,
				    s == NULL ? (char_u *)"" : s,
				    first);
			    *arg = c;
			    vim_free(tf);
			}
			clear_tv(&tv);
		    }
		}
	    }

	    vim_free(tofree);
	}

	arg = skipwhite(arg);
    }

    return arg;
}

/*
 * Set one item of ":let var = expr" or ":let [v1, v2] = list" to its value.
 * Returns a pointer to the char just after the var name.
 * Returns NULL if there is an error.
 */
    static char_u *
ex_let_one(
    char_u	*arg,		/* points to variable name */
    typval_T	*tv,		/* value to assign to variable */
    int		copy,		/* copy value from "tv" */
    char_u	*endchars,	/* valid chars after variable name  or NULL */
    char_u	*op)		/* "+", "-", "."  or NULL*/
{
    int		c1;
    char_u	*name;
    char_u	*p;
    char_u	*arg_end = NULL;
    int		len;
    int		opt_flags;
    char_u	*tofree = NULL;

    /*
     * ":let $VAR = expr": Set environment variable.
     */
    if (*arg == '$')
    {
	/* Find the end of the name. */
	++arg;
	name = arg;
	len = get_env_len(&arg);
	if (len == 0)
	    EMSG2(_(e_invarg2), name - 1);
	else
	{
	    if (op != NULL && (*op == '+' || *op == '-'))
		EMSG2(_(e_letwrong), op);
	    else if (endchars != NULL
			     && vim_strchr(endchars, *skipwhite(arg)) == NULL)
		EMSG(_(e_letunexp));
	    else if (!check_secure())
	    {
		c1 = name[len];
		name[len] = NUL;
		p = get_tv_string_chk(tv);
		if (p != NULL && op != NULL && *op == '.')
		{
		    int	    mustfree = FALSE;
		    char_u  *s = vim_getenv(name, &mustfree);

		    if (s != NULL)
		    {
			p = tofree = concat_str(s, p);
			if (mustfree)
			    vim_free(s);
		    }
		}
		if (p != NULL)
		{
		    vim_setenv(name, p);
		    if (STRICMP(name, "HOME") == 0)
			init_homedir();
		    else if (didset_vim && STRICMP(name, "VIM") == 0)
			didset_vim = FALSE;
		    else if (didset_vimruntime
					&& STRICMP(name, "VIMRUNTIME") == 0)
			didset_vimruntime = FALSE;
		    arg_end = arg;
		}
		name[len] = c1;
		vim_free(tofree);
	    }
	}
    }

    /*
     * ":let &option = expr": Set option value.
     * ":let &l:option = expr": Set local option value.
     * ":let &g:option = expr": Set global option value.
     */
    else if (*arg == '&')
    {
	/* Find the end of the name. */
	p = find_option_end(&arg, &opt_flags);
	if (p == NULL || (endchars != NULL
			      && vim_strchr(endchars, *skipwhite(p)) == NULL))
	    EMSG(_(e_letunexp));
	else
	{
	    long	n;
	    int		opt_type;
	    long	numval;
	    char_u	*stringval = NULL;
	    char_u	*s;

	    c1 = *p;
	    *p = NUL;

	    n = (long)get_tv_number(tv);
	    s = get_tv_string_chk(tv);	    /* != NULL if number or string */
	    if (s != NULL && op != NULL && *op != '=')
	    {
		opt_type = get_option_value(arg, &numval,
						       &stringval, opt_flags);
		if ((opt_type == 1 && *op == '.')
			|| (opt_type == 0 && *op != '.'))
		    EMSG2(_(e_letwrong), op);
		else
		{
		    if (opt_type == 1)  /* number */
		    {
			if (*op == '+')
			    n = numval + n;
			else
			    n = numval - n;
		    }
		    else if (opt_type == 0 && stringval != NULL) /* string */
		    {
			s = concat_str(stringval, s);
			vim_free(stringval);
			stringval = s;
		    }
		}
	    }
	    if (s != NULL)
	    {
		set_option_value(arg, n, s, opt_flags);
		arg_end = p;
	    }
	    *p = c1;
	    vim_free(stringval);
	}
    }

    /*
     * ":let @r = expr": Set register contents.
     */
    else if (*arg == '@')
    {
	++arg;
	if (op != NULL && (*op == '+' || *op == '-'))
	    EMSG2(_(e_letwrong), op);
	else if (endchars != NULL
			 && vim_strchr(endchars, *skipwhite(arg + 1)) == NULL)
	    EMSG(_(e_letunexp));
	else
	{
	    char_u	*ptofree = NULL;
	    char_u	*s;

	    p = get_tv_string_chk(tv);
	    if (p != NULL && op != NULL && *op == '.')
	    {
		s = get_reg_contents(*arg == '@' ? '"' : *arg, GREG_EXPR_SRC);
		if (s != NULL)
		{
		    p = ptofree = concat_str(s, p);
		    vim_free(s);
		}
	    }
	    if (p != NULL)
	    {
		write_reg_contents(*arg == '@' ? '"' : *arg, p, -1, FALSE);
		arg_end = arg + 1;
	    }
	    vim_free(ptofree);
	}
    }

    /*
     * ":let var = expr": Set internal variable.
     * ":let {expr} = expr": Idem, name made with curly braces
     */
    else if (eval_isnamec1(*arg) || *arg == '{')
    {
	lval_T	lv;

	p = get_lval(arg, tv, &lv, FALSE, FALSE, 0, FNE_CHECK_START);
	if (p != NULL && lv.ll_name != NULL)
	{
	    if (endchars != NULL && vim_strchr(endchars, *skipwhite(p)) == NULL)
		EMSG(_(e_letunexp));
	    else
	    {
		set_var_lval(&lv, p, tv, copy, op);
		arg_end = p;
	    }
	}
	clear_lval(&lv);
    }

    else
	EMSG2(_(e_invarg2), arg);

    return arg_end;
}

/*
 * Get an lval: variable, Dict item or List item that can be assigned a value
 * to: "name", "na{me}", "name[expr]", "name[expr:expr]", "name[expr][expr]",
 * "name.key", "name.key[expr]" etc.
 * Indexing only works if "name" is an existing List or Dictionary.
 * "name" points to the start of the name.
 * If "rettv" is not NULL it points to the value to be assigned.
 * "unlet" is TRUE for ":unlet": slightly different behavior when something is
 * wrong; must end in space or cmd separator.
 *
 * flags:
 *  GLV_QUIET:       do not give error messages
 *  GLV_READ_ONLY:   will not change the variable
 *  GLV_NO_AUTOLOAD: do not use script autoloading
 *
 * Returns a pointer to just after the name, including indexes.
 * When an evaluation error occurs "lp->ll_name" is NULL;
 * Returns NULL for a parsing error.  Still need to free items in "lp"!
 */
    char_u *
get_lval(
    char_u	*name,
    typval_T	*rettv,
    lval_T	*lp,
    int		unlet,
    int		skip,
    int		flags,	    /* GLV_ values */
    int		fne_flags)  /* flags for find_name_end() */
{
    char_u	*p;
    char_u	*expr_start, *expr_end;
    int		cc;
    dictitem_T	*v;
    typval_T	var1;
    typval_T	var2;
    int		empty1 = FALSE;
    listitem_T	*ni;
    char_u	*key = NULL;
    int		len;
    hashtab_T	*ht;
    int		quiet = flags & GLV_QUIET;

    /* Clear everything in "lp". */
    vim_memset(lp, 0, sizeof(lval_T));

    if (skip)
    {
	/* When skipping just find the end of the name. */
	lp->ll_name = name;
	return find_name_end(name, NULL, NULL, FNE_INCL_BR | fne_flags);
    }

    /* Find the end of the name. */
    p = find_name_end(name, &expr_start, &expr_end, fne_flags);
    if (expr_start != NULL)
    {
	/* Don't expand the name when we already know there is an error. */
	if (unlet && !VIM_ISWHITE(*p) && !ends_excmd(*p)
						    && *p != '[' && *p != '.')
	{
	    EMSG(_(e_trailing));
	    return NULL;
	}

	lp->ll_exp_name = make_expanded_name(name, expr_start, expr_end, p);
	if (lp->ll_exp_name == NULL)
	{
	    /* Report an invalid expression in braces, unless the
	     * expression evaluation has been cancelled due to an
	     * aborting error, an interrupt, or an exception. */
	    if (!aborting() && !quiet)
	    {
		emsg_severe = TRUE;
		EMSG2(_(e_invarg2), name);
		return NULL;
	    }
	}
	lp->ll_name = lp->ll_exp_name;
    }
    else
	lp->ll_name = name;

    /* Without [idx] or .key we are done. */
    if ((*p != '[' && *p != '.') || lp->ll_name == NULL)
	return p;

    cc = *p;
    *p = NUL;
    v = find_var(lp->ll_name, &ht, flags & GLV_NO_AUTOLOAD);
    if (v == NULL && !quiet)
	EMSG2(_(e_undefvar), lp->ll_name);
    *p = cc;
    if (v == NULL)
	return NULL;

    /*
     * Loop until no more [idx] or .key is following.
     */
    lp->ll_tv = &v->di_tv;
    var1.v_type = VAR_UNKNOWN;
    var2.v_type = VAR_UNKNOWN;
    while (*p == '[' || (*p == '.' && lp->ll_tv->v_type == VAR_DICT))
    {
	if (!(lp->ll_tv->v_type == VAR_LIST && lp->ll_tv->vval.v_list != NULL)
		&& !(lp->ll_tv->v_type == VAR_DICT
					   && lp->ll_tv->vval.v_dict != NULL))
	{
	    if (!quiet)
		EMSG(_("E689: Can only index a List or Dictionary"));
	    return NULL;
	}
	if (lp->ll_range)
	{
	    if (!quiet)
		EMSG(_("E708: [:] must come last"));
	    return NULL;
	}

	len = -1;
	if (*p == '.')
	{
	    key = p + 1;
	    for (len = 0; ASCII_ISALNUM(key[len]) || key[len] == '_'; ++len)
		;
	    if (len == 0)
	    {
		if (!quiet)
		    EMSG(_(e_emptykey));
		return NULL;
	    }
	    p = key + len;
	}
	else
	{
	    /* Get the index [expr] or the first index [expr: ]. */
	    p = skipwhite(p + 1);
	    if (*p == ':')
		empty1 = TRUE;
	    else
	    {
		empty1 = FALSE;
		if (eval1(&p, &var1, TRUE) == FAIL)	/* recursive! */
		    return NULL;
		if (get_tv_string_chk(&var1) == NULL)
		{
		    /* not a number or string */
		    clear_tv(&var1);
		    return NULL;
		}
	    }

	    /* Optionally get the second index [ :expr]. */
	    if (*p == ':')
	    {
		if (lp->ll_tv->v_type == VAR_DICT)
		{
		    if (!quiet)
			EMSG(_(e_dictrange));
		    clear_tv(&var1);
		    return NULL;
		}
		if (rettv != NULL && (rettv->v_type != VAR_LIST
					       || rettv->vval.v_list == NULL))
		{
		    if (!quiet)
			EMSG(_("E709: [:] requires a List value"));
		    clear_tv(&var1);
		    return NULL;
		}
		p = skipwhite(p + 1);
		if (*p == ']')
		    lp->ll_empty2 = TRUE;
		else
		{
		    lp->ll_empty2 = FALSE;
		    if (eval1(&p, &var2, TRUE) == FAIL)	/* recursive! */
		    {
			clear_tv(&var1);
			return NULL;
		    }
		    if (get_tv_string_chk(&var2) == NULL)
		    {
			/* not a number or string */
			clear_tv(&var1);
			clear_tv(&var2);
			return NULL;
		    }
		}
		lp->ll_range = TRUE;
	    }
	    else
		lp->ll_range = FALSE;

	    if (*p != ']')
	    {
		if (!quiet)
		    EMSG(_(e_missbrac));
		clear_tv(&var1);
		clear_tv(&var2);
		return NULL;
	    }

	    /* Skip to past ']'. */
	    ++p;
	}

	if (lp->ll_tv->v_type == VAR_DICT)
	{
	    if (len == -1)
	    {
		/* "[key]": get key from "var1" */
		key = get_tv_string_chk(&var1);	/* is number or string */
		if (key == NULL)
		{
		    clear_tv(&var1);
		    return NULL;
		}
	    }
	    lp->ll_list = NULL;
	    lp->ll_dict = lp->ll_tv->vval.v_dict;
	    lp->ll_di = dict_find(lp->ll_dict, key, len);

	    /* When assigning to a scope dictionary check that a function and
	     * variable name is valid (only variable name unless it is l: or
	     * g: dictionary). Disallow overwriting a builtin function. */
	    if (rettv != NULL && lp->ll_dict->dv_scope != 0)
	    {
		int prevval;
		int wrong;

		if (len != -1)
		{
		    prevval = key[len];
		    key[len] = NUL;
		}
		else
		    prevval = 0; /* avoid compiler warning */
		wrong = (lp->ll_dict->dv_scope == VAR_DEF_SCOPE
			       && rettv->v_type == VAR_FUNC
			       && var_check_func_name(key, lp->ll_di == NULL))
			|| !valid_varname(key);
		if (len != -1)
		    key[len] = prevval;
		if (wrong)
		    return NULL;
	    }

	    if (lp->ll_di == NULL)
	    {
		/* Can't add "v:" variable. */
		if (lp->ll_dict == &vimvardict)
		{
		    EMSG2(_(e_illvar), name);
		    return NULL;
		}

		/* Key does not exist in dict: may need to add it. */
		if (*p == '[' || *p == '.' || unlet)
		{
		    if (!quiet)
			EMSG2(_(e_dictkey), key);
		    clear_tv(&var1);
		    return NULL;
		}
		if (len == -1)
		    lp->ll_newkey = vim_strsave(key);
		else
		    lp->ll_newkey = vim_strnsave(key, len);
		clear_tv(&var1);
		if (lp->ll_newkey == NULL)
		    p = NULL;
		break;
	    }
	    /* existing variable, need to check if it can be changed */
	    else if ((flags & GLV_READ_ONLY) == 0
			     && var_check_ro(lp->ll_di->di_flags, name, FALSE))
	    {
		clear_tv(&var1);
		return NULL;
	    }

	    clear_tv(&var1);
	    lp->ll_tv = &lp->ll_di->di_tv;
	}
	else
	{
	    /*
	     * Get the number and item for the only or first index of the List.
	     */
	    if (empty1)
		lp->ll_n1 = 0;
	    else
		/* is number or string */
		lp->ll_n1 = (long)get_tv_number(&var1);
	    clear_tv(&var1);

	    lp->ll_dict = NULL;
	    lp->ll_list = lp->ll_tv->vval.v_list;
	    lp->ll_li = list_find(lp->ll_list, lp->ll_n1);
	    if (lp->ll_li == NULL)
	    {
		if (lp->ll_n1 < 0)
		{
		    lp->ll_n1 = 0;
		    lp->ll_li = list_find(lp->ll_list, lp->ll_n1);
		}
	    }
	    if (lp->ll_li == NULL)
	    {
		clear_tv(&var2);
		if (!quiet)
		    EMSGN(_(e_listidx), lp->ll_n1);
		return NULL;
	    }

	    /*
	     * May need to find the item or absolute index for the second
	     * index of a range.
	     * When no index given: "lp->ll_empty2" is TRUE.
	     * Otherwise "lp->ll_n2" is set to the second index.
	     */
	    if (lp->ll_range && !lp->ll_empty2)
	    {
		lp->ll_n2 = (long)get_tv_number(&var2);
						    /* is number or string */
		clear_tv(&var2);
		if (lp->ll_n2 < 0)
		{
		    ni = list_find(lp->ll_list, lp->ll_n2);
		    if (ni == NULL)
		    {
			if (!quiet)
			    EMSGN(_(e_listidx), lp->ll_n2);
			return NULL;
		    }
		    lp->ll_n2 = list_idx_of_item(lp->ll_list, ni);
		}

		/* Check that lp->ll_n2 isn't before lp->ll_n1. */
		if (lp->ll_n1 < 0)
		    lp->ll_n1 = list_idx_of_item(lp->ll_list, lp->ll_li);
		if (lp->ll_n2 < lp->ll_n1)
		{
		    if (!quiet)
			EMSGN(_(e_listidx), lp->ll_n2);
		    return NULL;
		}
	    }

	    lp->ll_tv = &lp->ll_li->li_tv;
	}
    }

    clear_tv(&var1);
    return p;
}

/*
 * Clear lval "lp" that was filled by get_lval().
 */
    void
clear_lval(lval_T *lp)
{
    vim_free(lp->ll_exp_name);
    vim_free(lp->ll_newkey);
}

/*
 * Set a variable that was parsed by get_lval() to "rettv".
 * "endp" points to just after the parsed name.
 * "op" is NULL, "+" for "+=", "-" for "-=", "." for ".=" or "=" for "=".
 */
    static void
set_var_lval(
    lval_T	*lp,
    char_u	*endp,
    typval_T	*rettv,
    int		copy,
    char_u	*op)
{
    int		cc;
    listitem_T	*ri;
    dictitem_T	*di;

    if (lp->ll_tv == NULL)
    {
	cc = *endp;
	*endp = NUL;
	if (op != NULL && *op != '=')
	{
	    typval_T tv;

	    /* handle +=, -= and .= */
	    di = NULL;
	    if (get_var_tv(lp->ll_name, (int)STRLEN(lp->ll_name),
					     &tv, &di, TRUE, FALSE) == OK)
	    {
		if ((di == NULL
		       || (!var_check_ro(di->di_flags, lp->ll_name, FALSE)
			  && !tv_check_lock(di->di_tv.v_lock, lp->ll_name,
								  FALSE)))
			&& tv_op(&tv, rettv, op) == OK)
		    set_var(lp->ll_name, &tv, FALSE);
		clear_tv(&tv);
	    }
	}
	else
	    set_var(lp->ll_name, rettv, copy);
	*endp = cc;
    }
    else if (tv_check_lock(lp->ll_newkey == NULL
		? lp->ll_tv->v_lock
		: lp->ll_tv->vval.v_dict->dv_lock, lp->ll_name, FALSE))
	;
    else if (lp->ll_range)
    {
	listitem_T *ll_li = lp->ll_li;
	int ll_n1 = lp->ll_n1;

	/*
	 * Check whether any of the list items is locked
	 */
	for (ri = rettv->vval.v_list->lv_first; ri != NULL && ll_li != NULL; )
	{
	    if (tv_check_lock(ll_li->li_tv.v_lock, lp->ll_name, FALSE))
		return;
	    ri = ri->li_next;
	    if (ri == NULL || (!lp->ll_empty2 && lp->ll_n2 == ll_n1))
		break;
	    ll_li = ll_li->li_next;
	    ++ll_n1;
	}

	/*
	 * Assign the List values to the list items.
	 */
	for (ri = rettv->vval.v_list->lv_first; ri != NULL; )
	{
	    if (op != NULL && *op != '=')
		tv_op(&lp->ll_li->li_tv, &ri->li_tv, op);
	    else
	    {
		clear_tv(&lp->ll_li->li_tv);
		copy_tv(&ri->li_tv, &lp->ll_li->li_tv);
	    }
	    ri = ri->li_next;
	    if (ri == NULL || (!lp->ll_empty2 && lp->ll_n2 == lp->ll_n1))
		break;
	    if (lp->ll_li->li_next == NULL)
	    {
		/* Need to add an empty item. */
		if (list_append_number(lp->ll_list, 0) == FAIL)
		{
		    ri = NULL;
		    break;
		}
	    }
	    lp->ll_li = lp->ll_li->li_next;
	    ++lp->ll_n1;
	}
	if (ri != NULL)
	    EMSG(_("E710: List value has more items than target"));
	else if (lp->ll_empty2
		? (lp->ll_li != NULL && lp->ll_li->li_next != NULL)
		: lp->ll_n1 != lp->ll_n2)
	    EMSG(_("E711: List value has not enough items"));
    }
    else
    {
	/*
	 * Assign to a List or Dictionary item.
	 */
	if (lp->ll_newkey != NULL)
	{
	    if (op != NULL && *op != '=')
	    {
		EMSG2(_(e_letwrong), op);
		return;
	    }

	    /* Need to add an item to the Dictionary. */
	    di = dictitem_alloc(lp->ll_newkey);
	    if (di == NULL)
		return;
	    if (dict_add(lp->ll_tv->vval.v_dict, di) == FAIL)
	    {
		vim_free(di);
		return;
	    }
	    lp->ll_tv = &di->di_tv;
	}
	else if (op != NULL && *op != '=')
	{
	    tv_op(lp->ll_tv, rettv, op);
	    return;
	}
	else
	    clear_tv(lp->ll_tv);

	/*
	 * Assign the value to the variable or list item.
	 */
	if (copy)
	    copy_tv(rettv, lp->ll_tv);
	else
	{
	    *lp->ll_tv = *rettv;
	    lp->ll_tv->v_lock = 0;
	    init_tv(rettv);
	}
    }
}

/*
 * Handle "tv1 += tv2", "tv1 -= tv2" and "tv1 .= tv2"
 * Returns OK or FAIL.
 */
    static int
tv_op(typval_T *tv1, typval_T *tv2, char_u *op)
{
    varnumber_T	n;
    char_u	numbuf[NUMBUFLEN];
    char_u	*s;

    /* Can't do anything with a Funcref, Dict, v:true on the right. */
    if (tv2->v_type != VAR_FUNC && tv2->v_type != VAR_DICT
						&& tv2->v_type != VAR_SPECIAL)
    {
	switch (tv1->v_type)
	{
	    case VAR_UNKNOWN:
	    case VAR_DICT:
	    case VAR_FUNC:
	    case VAR_PARTIAL:
	    case VAR_SPECIAL:
	    case VAR_JOB:
	    case VAR_CHANNEL:
		break;

	    case VAR_LIST:
		if (*op != '+' || tv2->v_type != VAR_LIST)
		    break;
		/* List += List */
		if (tv1->vval.v_list != NULL && tv2->vval.v_list != NULL)
		    list_extend(tv1->vval.v_list, tv2->vval.v_list, NULL);
		return OK;

	    case VAR_NUMBER:
	    case VAR_STRING:
		if (tv2->v_type == VAR_LIST)
		    break;
		if (*op == '+' || *op == '-')
		{
		    /* nr += nr  or  nr -= nr*/
		    n = get_tv_number(tv1);
#ifdef FEAT_FLOAT
		    if (tv2->v_type == VAR_FLOAT)
		    {
			float_T f = n;

			if (*op == '+')
			    f += tv2->vval.v_float;
			else
			    f -= tv2->vval.v_float;
			clear_tv(tv1);
			tv1->v_type = VAR_FLOAT;
			tv1->vval.v_float = f;
		    }
		    else
#endif
		    {
			if (*op == '+')
			    n += get_tv_number(tv2);
			else
			    n -= get_tv_number(tv2);
			clear_tv(tv1);
			tv1->v_type = VAR_NUMBER;
			tv1->vval.v_number = n;
		    }
		}
		else
		{
		    if (tv2->v_type == VAR_FLOAT)
			break;

		    /* str .= str */
		    s = get_tv_string(tv1);
		    s = concat_str(s, get_tv_string_buf(tv2, numbuf));
		    clear_tv(tv1);
		    tv1->v_type = VAR_STRING;
		    tv1->vval.v_string = s;
		}
		return OK;

	    case VAR_FLOAT:
#ifdef FEAT_FLOAT
		{
		    float_T f;

		    if (*op == '.' || (tv2->v_type != VAR_FLOAT
				    && tv2->v_type != VAR_NUMBER
				    && tv2->v_type != VAR_STRING))
			break;
		    if (tv2->v_type == VAR_FLOAT)
			f = tv2->vval.v_float;
		    else
			f = get_tv_number(tv2);
		    if (*op == '+')
			tv1->vval.v_float += f;
		    else
			tv1->vval.v_float -= f;
		}
#endif
		return OK;
	}
    }

    EMSG2(_(e_letwrong), op);
    return FAIL;
}

/*
 * Evaluate the expression used in a ":for var in expr" command.
 * "arg" points to "var".
 * Set "*errp" to TRUE for an error, FALSE otherwise;
 * Return a pointer that holds the info.  Null when there is an error.
 */
    void *
eval_for_line(
    char_u	*arg,
    int		*errp,
    char_u	**nextcmdp,
    int		skip)
{
    forinfo_T	*fi;
    char_u	*expr;
    typval_T	tv;
    list_T	*l;

    *errp = TRUE;	/* default: there is an error */

    fi = (forinfo_T *)alloc_clear(sizeof(forinfo_T));
    if (fi == NULL)
	return NULL;

    expr = skip_var_list(arg, &fi->fi_varcount, &fi->fi_semicolon);
    if (expr == NULL)
	return fi;

    expr = skipwhite(expr);
    if (expr[0] != 'i' || expr[1] != 'n' || !VIM_ISWHITE(expr[2]))
    {
	EMSG(_("E690: Missing \"in\" after :for"));
	return fi;
    }

    if (skip)
	++emsg_skip;
    if (eval0(skipwhite(expr + 2), &tv, nextcmdp, !skip) == OK)
    {
	*errp = FALSE;
	if (!skip)
	{
	    l = tv.vval.v_list;
	    if (tv.v_type != VAR_LIST)
	    {
		EMSG(_(e_listreq));
		clear_tv(&tv);
	    }
	    else if (l == NULL)
	    {
		/* a null list is like an empty list: do nothing */
		clear_tv(&tv);
	    }
	    else
	    {
		/* No need to increment the refcount, it's already set for the
		 * list being used in "tv". */
		fi->fi_list = l;
		list_add_watch(l, &fi->fi_lw);
		fi->fi_lw.lw_item = l->lv_first;
	    }
	}
    }
    if (skip)
	--emsg_skip;

    return fi;
}

/*
 * Use the first item in a ":for" list.  Advance to the next.
 * Assign the values to the variable (list).  "arg" points to the first one.
 * Return TRUE when a valid item was found, FALSE when at end of list or
 * something wrong.
 */
    int
next_for_item(void *fi_void, char_u *arg)
{
    forinfo_T	*fi = (forinfo_T *)fi_void;
    int		result;
    listitem_T	*item;

    item = fi->fi_lw.lw_item;
    if (item == NULL)
	result = FALSE;
    else
    {
	fi->fi_lw.lw_item = item->li_next;
	result = (ex_let_vars(arg, &item->li_tv, TRUE,
			      fi->fi_semicolon, fi->fi_varcount, NULL) == OK);
    }
    return result;
}

/*
 * Free the structure used to store info used by ":for".
 */
    void
free_for_info(void *fi_void)
{
    forinfo_T    *fi = (forinfo_T *)fi_void;

    if (fi != NULL && fi->fi_list != NULL)
    {
	list_rem_watch(fi->fi_list, &fi->fi_lw);
	list_unref(fi->fi_list);
    }
    vim_free(fi);
}

#if defined(FEAT_CMDL_COMPL) || defined(PROTO)

    void
set_context_for_expression(
    expand_T	*xp,
    char_u	*arg,
    cmdidx_T	cmdidx)
{
    int		got_eq = FALSE;
    int		c;
    char_u	*p;

    if (cmdidx == CMD_let)
    {
	xp->xp_context = EXPAND_USER_VARS;
	if (vim_strpbrk(arg, (char_u *)"\"'+-*/%.=!?~|&$([<>,#") == NULL)
	{
	    /* ":let var1 var2 ...": find last space. */
	    for (p = arg + STRLEN(arg); p >= arg; )
	    {
		xp->xp_pattern = p;
		MB_PTR_BACK(arg, p);
		if (VIM_ISWHITE(*p))
		    break;
	    }
	    return;
	}
    }
    else
	xp->xp_context = cmdidx == CMD_call ? EXPAND_FUNCTIONS
							  : EXPAND_EXPRESSION;
    while ((xp->xp_pattern = vim_strpbrk(arg,
				  (char_u *)"\"'+-*/%.=!?~|&$([<>,#")) != NULL)
    {
	c = *xp->xp_pattern;
	if (c == '&')
	{
	    c = xp->xp_pattern[1];
	    if (c == '&')
	    {
		++xp->xp_pattern;
		xp->xp_context = cmdidx != CMD_let || got_eq
					 ? EXPAND_EXPRESSION : EXPAND_NOTHING;
	    }
	    else if (c != ' ')
	    {
		xp->xp_context = EXPAND_SETTINGS;
		if ((c == 'l' || c == 'g') && xp->xp_pattern[2] == ':')
		    xp->xp_pattern += 2;

	    }
	}
	else if (c == '$')
	{
	    /* environment variable */
	    xp->xp_context = EXPAND_ENV_VARS;
	}
	else if (c == '=')
	{
	    got_eq = TRUE;
	    xp->xp_context = EXPAND_EXPRESSION;
	}
	else if (c == '#'
		&& xp->xp_context == EXPAND_EXPRESSION)
	{
	    /* Autoload function/variable contains '#'. */
	    break;
	}
	else if ((c == '<' || c == '#')
		&& xp->xp_context == EXPAND_FUNCTIONS
		&& vim_strchr(xp->xp_pattern, '(') == NULL)
	{
	    /* Function name can start with "<SNR>" and contain '#'. */
	    break;
	}
	else if (cmdidx != CMD_let || got_eq)
	{
	    if (c == '"')	    /* string */
	    {
		while ((c = *++xp->xp_pattern) != NUL && c != '"')
		    if (c == '\\' && xp->xp_pattern[1] != NUL)
			++xp->xp_pattern;
		xp->xp_context = EXPAND_NOTHING;
	    }
	    else if (c == '\'')	    /* literal string */
	    {
		/* Trick: '' is like stopping and starting a literal string. */
		while ((c = *++xp->xp_pattern) != NUL && c != '\'')
		    /* skip */ ;
		xp->xp_context = EXPAND_NOTHING;
	    }
	    else if (c == '|')
	    {
		if (xp->xp_pattern[1] == '|')
		{
		    ++xp->xp_pattern;
		    xp->xp_context = EXPAND_EXPRESSION;
		}
		else
		    xp->xp_context = EXPAND_COMMANDS;
	    }
	    else
		xp->xp_context = EXPAND_EXPRESSION;
	}
	else
	    /* Doesn't look like something valid, expand as an expression
	     * anyway. */
	    xp->xp_context = EXPAND_EXPRESSION;
	arg = xp->xp_pattern;
	if (*arg != NUL)
	    while ((c = *++arg) != NUL && (c == ' ' || c == '\t'))
		/* skip */ ;
    }
    xp->xp_pattern = arg;
}

#endif /* FEAT_CMDL_COMPL */

/*
 * ":unlet[!] var1 ... " command.
 */
    void
ex_unlet(exarg_T *eap)
{
    ex_unletlock(eap, eap->arg, 0);
}

/*
 * ":lockvar" and ":unlockvar" commands
 */
    void
ex_lockvar(exarg_T *eap)
{
    char_u	*arg = eap->arg;
    int		deep = 2;

    if (eap->forceit)
	deep = -1;
    else if (vim_isdigit(*arg))
    {
	deep = getdigits(&arg);
	arg = skipwhite(arg);
    }

    ex_unletlock(eap, arg, deep);
}

/*
 * ":unlet", ":lockvar" and ":unlockvar" are quite similar.
 */
    static void
ex_unletlock(
    exarg_T	*eap,
    char_u	*argstart,
    int		deep)
{
    char_u	*arg = argstart;
    char_u	*name_end;
    int		error = FALSE;
    lval_T	lv;

    do
    {
	/* Parse the name and find the end. */
	name_end = get_lval(arg, NULL, &lv, TRUE, eap->skip || error, 0,
							     FNE_CHECK_START);
	if (lv.ll_name == NULL)
	    error = TRUE;	    /* error but continue parsing */
	if (name_end == NULL || (!VIM_ISWHITE(*name_end)
						   && !ends_excmd(*name_end)))
	{
	    if (name_end != NULL)
	    {
		emsg_severe = TRUE;
		EMSG(_(e_trailing));
	    }
	    if (!(eap->skip || error))
		clear_lval(&lv);
	    break;
	}

	if (!error && !eap->skip)
	{
	    if (eap->cmdidx == CMD_unlet)
	    {
		if (do_unlet_var(&lv, name_end, eap->forceit) == FAIL)
		    error = TRUE;
	    }
	    else
	    {
		if (do_lock_var(&lv, name_end, deep,
					  eap->cmdidx == CMD_lockvar) == FAIL)
		    error = TRUE;
	    }
	}

	if (!eap->skip)
	    clear_lval(&lv);

	arg = skipwhite(name_end);
    } while (!ends_excmd(*arg));

    eap->nextcmd = check_nextcmd(arg);
}

    static int
do_unlet_var(
    lval_T	*lp,
    char_u	*name_end,
    int		forceit)
{
    int		ret = OK;
    int		cc;

    if (lp->ll_tv == NULL)
    {
	cc = *name_end;
	*name_end = NUL;

	/* Normal name or expanded name. */
	if (do_unlet(lp->ll_name, forceit) == FAIL)
	    ret = FAIL;
	*name_end = cc;
    }
    else if ((lp->ll_list != NULL
		   && tv_check_lock(lp->ll_list->lv_lock, lp->ll_name, FALSE))
	    || (lp->ll_dict != NULL
		  && tv_check_lock(lp->ll_dict->dv_lock, lp->ll_name, FALSE)))
	return FAIL;
    else if (lp->ll_range)
    {
	listitem_T    *li;
	listitem_T    *ll_li = lp->ll_li;
	int	      ll_n1 = lp->ll_n1;

	while (ll_li != NULL && (lp->ll_empty2 || lp->ll_n2 >= ll_n1))
	{
	    li = ll_li->li_next;
	    if (tv_check_lock(ll_li->li_tv.v_lock, lp->ll_name, FALSE))
		return FAIL;
	    ll_li = li;
	    ++ll_n1;
	}

	/* Delete a range of List items. */
	while (lp->ll_li != NULL && (lp->ll_empty2 || lp->ll_n2 >= lp->ll_n1))
	{
	    li = lp->ll_li->li_next;
	    listitem_remove(lp->ll_list, lp->ll_li);
	    lp->ll_li = li;
	    ++lp->ll_n1;
	}
    }
    else
    {
	if (lp->ll_list != NULL)
	    /* unlet a List item. */
	    listitem_remove(lp->ll_list, lp->ll_li);
	else
	    /* unlet a Dictionary item. */
	    dictitem_remove(lp->ll_dict, lp->ll_di);
    }

    return ret;
}

/*
 * "unlet" a variable.  Return OK if it existed, FAIL if not.
 * When "forceit" is TRUE don't complain if the variable doesn't exist.
 */
    int
do_unlet(char_u *name, int forceit)
{
    hashtab_T	*ht;
    hashitem_T	*hi;
    char_u	*varname;
    dict_T	*d;
    dictitem_T	*di;

    ht = find_var_ht(name, &varname);
    if (ht != NULL && *varname != NUL)
    {
	d = get_current_funccal_dict(ht);
	if (d == NULL)
	{
	    if (ht == &globvarht)
		d = &globvardict;
	    else if (ht == &compat_hashtab)
		d = &vimvardict;
	    else
	    {
		di = find_var_in_ht(ht, *name, (char_u *)"", FALSE);
		d = di == NULL ? NULL : di->di_tv.vval.v_dict;
	    }
	    if (d == NULL)
	    {
		internal_error("do_unlet()");
		return FAIL;
	    }
	}
	hi = hash_find(ht, varname);
	if (HASHITEM_EMPTY(hi))
	    hi = find_hi_in_scoped_ht(name, &ht);
	if (hi != NULL && !HASHITEM_EMPTY(hi))
	{
	    di = HI2DI(hi);
	    if (var_check_fixed(di->di_flags, name, FALSE)
		    || var_check_ro(di->di_flags, name, FALSE)
		    || tv_check_lock(d->dv_lock, name, FALSE))
		return FAIL;

	    delete_var(ht, hi);
	    return OK;
	}
    }
    if (forceit)
	return OK;
    EMSG2(_("E108: No such variable: \"%s\""), name);
    return FAIL;
}

/*
 * Lock or unlock variable indicated by "lp".
 * "deep" is the levels to go (-1 for unlimited);
 * "lock" is TRUE for ":lockvar", FALSE for ":unlockvar".
 */
    static int
do_lock_var(
    lval_T	*lp,
    char_u	*name_end,
    int		deep,
    int		lock)
{
    int		ret = OK;
    int		cc;
    dictitem_T	*di;

    if (deep == 0)	/* nothing to do */
	return OK;

    if (lp->ll_tv == NULL)
    {
	cc = *name_end;
	*name_end = NUL;

	/* Normal name or expanded name. */
	di = find_var(lp->ll_name, NULL, TRUE);
	if (di == NULL)
	    ret = FAIL;
	else if ((di->di_flags & DI_FLAGS_FIX)
			&& di->di_tv.v_type != VAR_DICT
			&& di->di_tv.v_type != VAR_LIST)
	    /* For historic reasons this error is not given for a list or dict.
	     * E.g., the b: dict could be locked/unlocked. */
	    EMSG2(_("E940: Cannot lock or unlock variable %s"), lp->ll_name);
	else
	{
	    if (lock)
		di->di_flags |= DI_FLAGS_LOCK;
	    else
		di->di_flags &= ~DI_FLAGS_LOCK;
	    item_lock(&di->di_tv, deep, lock);
	}
	*name_end = cc;
    }
    else if (lp->ll_range)
    {
	listitem_T    *li = lp->ll_li;

	/* (un)lock a range of List items. */
	while (li != NULL && (lp->ll_empty2 || lp->ll_n2 >= lp->ll_n1))
	{
	    item_lock(&li->li_tv, deep, lock);
	    li = li->li_next;
	    ++lp->ll_n1;
	}
    }
    else if (lp->ll_list != NULL)
	/* (un)lock a List item. */
	item_lock(&lp->ll_li->li_tv, deep, lock);
    else
	/* (un)lock a Dictionary item. */
	item_lock(&lp->ll_di->di_tv, deep, lock);

    return ret;
}

/*
 * Lock or unlock an item.  "deep" is nr of levels to go.
 */
    static void
item_lock(typval_T *tv, int deep, int lock)
{
    static int	recurse = 0;
    list_T	*l;
    listitem_T	*li;
    dict_T	*d;
    hashitem_T	*hi;
    int		todo;

    if (recurse >= DICT_MAXNEST)
    {
	EMSG(_("E743: variable nested too deep for (un)lock"));
	return;
    }
    if (deep == 0)
	return;
    ++recurse;

    /* lock/unlock the item itself */
    if (lock)
	tv->v_lock |= VAR_LOCKED;
    else
	tv->v_lock &= ~VAR_LOCKED;

    switch (tv->v_type)
    {
	case VAR_UNKNOWN:
	case VAR_NUMBER:
	case VAR_STRING:
	case VAR_FUNC:
	case VAR_PARTIAL:
	case VAR_FLOAT:
	case VAR_SPECIAL:
	case VAR_JOB:
	case VAR_CHANNEL:
	    break;

	case VAR_LIST:
	    if ((l = tv->vval.v_list) != NULL)
	    {
		if (lock)
		    l->lv_lock |= VAR_LOCKED;
		else
		    l->lv_lock &= ~VAR_LOCKED;
		if (deep < 0 || deep > 1)
		    /* recursive: lock/unlock the items the List contains */
		    for (li = l->lv_first; li != NULL; li = li->li_next)
			item_lock(&li->li_tv, deep - 1, lock);
	    }
	    break;
	case VAR_DICT:
	    if ((d = tv->vval.v_dict) != NULL)
	    {
		if (lock)
		    d->dv_lock |= VAR_LOCKED;
		else
		    d->dv_lock &= ~VAR_LOCKED;
		if (deep < 0 || deep > 1)
		{
		    /* recursive: lock/unlock the items the List contains */
		    todo = (int)d->dv_hashtab.ht_used;
		    for (hi = d->dv_hashtab.ht_array; todo > 0; ++hi)
		    {
			if (!HASHITEM_EMPTY(hi))
			{
			    --todo;
			    item_lock(&HI2DI(hi)->di_tv, deep - 1, lock);
			}
		    }
		}
	    }
    }
    --recurse;
}

#if (defined(FEAT_MENU) && defined(FEAT_MULTI_LANG)) || defined(PROTO)
/*
 * Delete all "menutrans_" variables.
 */
    void
del_menutrans_vars(void)
{
    hashitem_T	*hi;
    int		todo;

    hash_lock(&globvarht);
    todo = (int)globvarht.ht_used;
    for (hi = globvarht.ht_array; todo > 0 && !got_int; ++hi)
    {
	if (!HASHITEM_EMPTY(hi))
	{
	    --todo;
	    if (STRNCMP(HI2DI(hi)->di_key, "menutrans_", 10) == 0)
		delete_var(&globvarht, hi);
	}
    }
    hash_unlock(&globvarht);
}
#endif

#if defined(FEAT_CMDL_COMPL) || defined(PROTO)

/*
 * Local string buffer for the next two functions to store a variable name
 * with its prefix. Allocated in cat_prefix_varname(), freed later in
 * get_user_var_name().
 */

static char_u *cat_prefix_varname(int prefix, char_u *name);

static char_u	*varnamebuf = NULL;
static int	varnamebuflen = 0;

/*
 * Function to concatenate a prefix and a variable name.
 */
    static char_u *
cat_prefix_varname(int prefix, char_u *name)
{
    int		len;

    len = (int)STRLEN(name) + 3;
    if (len > varnamebuflen)
    {
	vim_free(varnamebuf);
	len += 10;			/* some additional space */
	varnamebuf = alloc(len);
	if (varnamebuf == NULL)
	{
	    varnamebuflen = 0;
	    return NULL;
	}
	varnamebuflen = len;
    }
    *varnamebuf = prefix;
    varnamebuf[1] = ':';
    STRCPY(varnamebuf + 2, name);
    return varnamebuf;
}

/*
 * Function given to ExpandGeneric() to obtain the list of user defined
 * (global/buffer/window/built-in) variable names.
 */
    char_u *
get_user_var_name(expand_T *xp, int idx)
{
    static long_u	gdone;
    static long_u	bdone;
    static long_u	wdone;
    static long_u	tdone;
    static int		vidx;
    static hashitem_T	*hi;
    hashtab_T		*ht;

    if (idx == 0)
    {
	gdone = bdone = wdone = vidx = 0;
	tdone = 0;
    }

    /* Global variables */
    if (gdone < globvarht.ht_used)
    {
	if (gdone++ == 0)
	    hi = globvarht.ht_array;
	else
	    ++hi;
	while (HASHITEM_EMPTY(hi))
	    ++hi;
	if (STRNCMP("g:", xp->xp_pattern, 2) == 0)
	    return cat_prefix_varname('g', hi->hi_key);
	return hi->hi_key;
    }

    /* b: variables */
    ht = &curbuf->b_vars->dv_hashtab;
    if (bdone < ht->ht_used)
    {
	if (bdone++ == 0)
	    hi = ht->ht_array;
	else
	    ++hi;
	while (HASHITEM_EMPTY(hi))
	    ++hi;
	return cat_prefix_varname('b', hi->hi_key);
    }

    /* w: variables */
    ht = &curwin->w_vars->dv_hashtab;
    if (wdone < ht->ht_used)
    {
	if (wdone++ == 0)
	    hi = ht->ht_array;
	else
	    ++hi;
	while (HASHITEM_EMPTY(hi))
	    ++hi;
	return cat_prefix_varname('w', hi->hi_key);
    }

    /* t: variables */
    ht = &curtab->tp_vars->dv_hashtab;
    if (tdone < ht->ht_used)
    {
	if (tdone++ == 0)
	    hi = ht->ht_array;
	else
	    ++hi;
	while (HASHITEM_EMPTY(hi))
	    ++hi;
	return cat_prefix_varname('t', hi->hi_key);
    }

    /* v: variables */
    if (vidx < VV_LEN)
	return cat_prefix_varname('v', (char_u *)vimvars[vidx++].vv_name);

    vim_free(varnamebuf);
    varnamebuf = NULL;
    varnamebuflen = 0;
    return NULL;
}

#endif /* FEAT_CMDL_COMPL */

/*
 * Return TRUE if "pat" matches "text".
 * Does not use 'cpo' and always uses 'magic'.
 */
    static int
pattern_match(char_u *pat, char_u *text, int ic)
{
    int		matches = FALSE;
    char_u	*save_cpo;
    regmatch_T	regmatch;

    /* avoid 'l' flag in 'cpoptions' */
    save_cpo = p_cpo;
    p_cpo = (char_u *)"";
    regmatch.regprog = vim_regcomp(pat, RE_MAGIC + RE_STRING);
    if (regmatch.regprog != NULL)
    {
	regmatch.rm_ic = ic;
	matches = vim_regexec_nl(&regmatch, text, (colnr_T)0);
	vim_regfree(regmatch.regprog);
    }
    p_cpo = save_cpo;
    return matches;
}

/*
 * types for expressions.
 */
typedef enum
{
    TYPE_UNKNOWN = 0
    , TYPE_EQUAL	/* == */
    , TYPE_NEQUAL	/* != */
    , TYPE_GREATER	/* >  */
    , TYPE_GEQUAL	/* >= */
    , TYPE_SMALLER	/* <  */
    , TYPE_SEQUAL	/* <= */
    , TYPE_MATCH	/* =~ */
    , TYPE_NOMATCH	/* !~ */
} exptype_T;

/*
 * The "evaluate" argument: When FALSE, the argument is only parsed but not
 * executed.  The function may return OK, but the rettv will be of type
 * VAR_UNKNOWN.  The function still returns FAIL for a syntax error.
 */

/*
 * Handle zero level expression.
 * This calls eval1() and handles error message and nextcmd.
 * Put the result in "rettv" when returning OK and "evaluate" is TRUE.
 * Note: "rettv.v_lock" is not set.
 * Return OK or FAIL.
 */
    int
eval0(
    char_u	*arg,
    typval_T	*rettv,
    char_u	**nextcmd,
    int		evaluate)
{
    int		ret;
    char_u	*p;

    p = skipwhite(arg);
    ret = eval1(&p, rettv, evaluate);
    if (ret == FAIL || !ends_excmd(*p))
    {
	if (ret != FAIL)
	    clear_tv(rettv);
	/*
	 * Report the invalid expression unless the expression evaluation has
	 * been cancelled due to an aborting error, an interrupt, or an
	 * exception.
	 */
	if (!aborting())
	    EMSG2(_(e_invexpr2), arg);
	ret = FAIL;
    }
    if (nextcmd != NULL)
	*nextcmd = check_nextcmd(p);

    return ret;
}

/*
 * Handle top level expression:
 *	expr2 ? expr1 : expr1
 *
 * "arg" must point to the first non-white of the expression.
 * "arg" is advanced to the next non-white after the recognized expression.
 *
 * Note: "rettv.v_lock" is not set.
 *
 * Return OK or FAIL.
 */
    int
eval1(char_u **arg, typval_T *rettv, int evaluate)
{
    int		result;
    typval_T	var2;

    /*
     * Get the first variable.
     */
    if (eval2(arg, rettv, evaluate) == FAIL)
	return FAIL;

    if ((*arg)[0] == '?')
    {
	result = FALSE;
	if (evaluate)
	{
	    int		error = FALSE;

	    if (get_tv_number_chk(rettv, &error) != 0)
		result = TRUE;
	    clear_tv(rettv);
	    if (error)
		return FAIL;
	}

	/*
	 * Get the second variable.
	 */
	*arg = skipwhite(*arg + 1);
	if (eval1(arg, rettv, evaluate && result) == FAIL) /* recursive! */
	    return FAIL;

	/*
	 * Check for the ":".
	 */
	if ((*arg)[0] != ':')
	{
	    EMSG(_("E109: Missing ':' after '?'"));
	    if (evaluate && result)
		clear_tv(rettv);
	    return FAIL;
	}

	/*
	 * Get the third variable.
	 */
	*arg = skipwhite(*arg + 1);
	if (eval1(arg, &var2, evaluate && !result) == FAIL) /* recursive! */
	{
	    if (evaluate && result)
		clear_tv(rettv);
	    return FAIL;
	}
	if (evaluate && !result)
	    *rettv = var2;
    }

    return OK;
}

/*
 * Handle first level expression:
 *	expr2 || expr2 || expr2	    logical OR
 *
 * "arg" must point to the first non-white of the expression.
 * "arg" is advanced to the next non-white after the recognized expression.
 *
 * Return OK or FAIL.
 */
    static int
eval2(char_u **arg, typval_T *rettv, int evaluate)
{
    typval_T	var2;
    long	result;
    int		first;
    int		error = FALSE;

    /*
     * Get the first variable.
     */
    if (eval3(arg, rettv, evaluate) == FAIL)
	return FAIL;

    /*
     * Repeat until there is no following "||".
     */
    first = TRUE;
    result = FALSE;
    while ((*arg)[0] == '|' && (*arg)[1] == '|')
    {
	if (evaluate && first)
	{
	    if (get_tv_number_chk(rettv, &error) != 0)
		result = TRUE;
	    clear_tv(rettv);
	    if (error)
		return FAIL;
	    first = FALSE;
	}

	/*
	 * Get the second variable.
	 */
	*arg = skipwhite(*arg + 2);
	if (eval3(arg, &var2, evaluate && !result) == FAIL)
	    return FAIL;

	/*
	 * Compute the result.
	 */
	if (evaluate && !result)
	{
	    if (get_tv_number_chk(&var2, &error) != 0)
		result = TRUE;
	    clear_tv(&var2);
	    if (error)
		return FAIL;
	}
	if (evaluate)
	{
	    rettv->v_type = VAR_NUMBER;
	    rettv->vval.v_number = result;
	}
    }

    return OK;
}

/*
 * Handle second level expression:
 *	expr3 && expr3 && expr3	    logical AND
 *
 * "arg" must point to the first non-white of the expression.
 * "arg" is advanced to the next non-white after the recognized expression.
 *
 * Return OK or FAIL.
 */
    static int
eval3(char_u **arg, typval_T *rettv, int evaluate)
{
    typval_T	var2;
    long	result;
    int		first;
    int		error = FALSE;

    /*
     * Get the first variable.
     */
    if (eval4(arg, rettv, evaluate) == FAIL)
	return FAIL;

    /*
     * Repeat until there is no following "&&".
     */
    first = TRUE;
    result = TRUE;
    while ((*arg)[0] == '&' && (*arg)[1] == '&')
    {
	if (evaluate && first)
	{
	    if (get_tv_number_chk(rettv, &error) == 0)
		result = FALSE;
	    clear_tv(rettv);
	    if (error)
		return FAIL;
	    first = FALSE;
	}

	/*
	 * Get the second variable.
	 */
	*arg = skipwhite(*arg + 2);
	if (eval4(arg, &var2, evaluate && result) == FAIL)
	    return FAIL;

	/*
	 * Compute the result.
	 */
	if (evaluate && result)
	{
	    if (get_tv_number_chk(&var2, &error) == 0)
		result = FALSE;
	    clear_tv(&var2);
	    if (error)
		return FAIL;
	}
	if (evaluate)
	{
	    rettv->v_type = VAR_NUMBER;
	    rettv->vval.v_number = result;
	}
    }

    return OK;
}

/*
 * Handle third level expression:
 *	var1 == var2
 *	var1 =~ var2
 *	var1 != var2
 *	var1 !~ var2
 *	var1 > var2
 *	var1 >= var2
 *	var1 < var2
 *	var1 <= var2
 *	var1 is var2
 *	var1 isnot var2
 *
 * "arg" must point to the first non-white of the expression.
 * "arg" is advanced to the next non-white after the recognized expression.
 *
 * Return OK or FAIL.
 */
    static int
eval4(char_u **arg, typval_T *rettv, int evaluate)
{
    typval_T	var2;
    char_u	*p;
    int		i;
    exptype_T	type = TYPE_UNKNOWN;
    int		type_is = FALSE;    /* TRUE for "is" and "isnot" */
    int		len = 2;
    varnumber_T	n1, n2;
    char_u	*s1, *s2;
    char_u	buf1[NUMBUFLEN], buf2[NUMBUFLEN];
    int		ic;

    /*
     * Get the first variable.
     */
    if (eval5(arg, rettv, evaluate) == FAIL)
	return FAIL;

    p = *arg;
    switch (p[0])
    {
	case '=':   if (p[1] == '=')
			type = TYPE_EQUAL;
		    else if (p[1] == '~')
			type = TYPE_MATCH;
		    break;
	case '!':   if (p[1] == '=')
			type = TYPE_NEQUAL;
		    else if (p[1] == '~')
			type = TYPE_NOMATCH;
		    break;
	case '>':   if (p[1] != '=')
		    {
			type = TYPE_GREATER;
			len = 1;
		    }
		    else
			type = TYPE_GEQUAL;
		    break;
	case '<':   if (p[1] != '=')
		    {
			type = TYPE_SMALLER;
			len = 1;
		    }
		    else
			type = TYPE_SEQUAL;
		    break;
	case 'i':   if (p[1] == 's')
		    {
			if (p[2] == 'n' && p[3] == 'o' && p[4] == 't')
			    len = 5;
			i = p[len];
			if (!isalnum(i) && i != '_')
			{
			    type = len == 2 ? TYPE_EQUAL : TYPE_NEQUAL;
			    type_is = TRUE;
			}
		    }
		    break;
    }

    /*
     * If there is a comparative operator, use it.
     */
    if (type != TYPE_UNKNOWN)
    {
	/* extra question mark appended: ignore case */
	if (p[len] == '?')
	{
	    ic = TRUE;
	    ++len;
	}
	/* extra '#' appended: match case */
	else if (p[len] == '#')
	{
	    ic = FALSE;
	    ++len;
	}
	/* nothing appended: use 'ignorecase' */
	else
	    ic = p_ic;

	/*
	 * Get the second variable.
	 */
	*arg = skipwhite(p + len);
	if (eval5(arg, &var2, evaluate) == FAIL)
	{
	    clear_tv(rettv);
	    return FAIL;
	}

	if (evaluate)
	{
	    if (type_is && rettv->v_type != var2.v_type)
	    {
		/* For "is" a different type always means FALSE, for "notis"
		 * it means TRUE. */
		n1 = (type == TYPE_NEQUAL);
	    }
	    else if (rettv->v_type == VAR_LIST || var2.v_type == VAR_LIST)
	    {
		if (type_is)
		{
		    n1 = (rettv->v_type == var2.v_type
				   && rettv->vval.v_list == var2.vval.v_list);
		    if (type == TYPE_NEQUAL)
			n1 = !n1;
		}
		else if (rettv->v_type != var2.v_type
			|| (type != TYPE_EQUAL && type != TYPE_NEQUAL))
		{
		    if (rettv->v_type != var2.v_type)
			EMSG(_("E691: Can only compare List with List"));
		    else
			EMSG(_("E692: Invalid operation for List"));
		    clear_tv(rettv);
		    clear_tv(&var2);
		    return FAIL;
		}
		else
		{
		    /* Compare two Lists for being equal or unequal. */
		    n1 = list_equal(rettv->vval.v_list, var2.vval.v_list,
								   ic, FALSE);
		    if (type == TYPE_NEQUAL)
			n1 = !n1;
		}
	    }

	    else if (rettv->v_type == VAR_DICT || var2.v_type == VAR_DICT)
	    {
		if (type_is)
		{
		    n1 = (rettv->v_type == var2.v_type
				   && rettv->vval.v_dict == var2.vval.v_dict);
		    if (type == TYPE_NEQUAL)
			n1 = !n1;
		}
		else if (rettv->v_type != var2.v_type
			|| (type != TYPE_EQUAL && type != TYPE_NEQUAL))
		{
		    if (rettv->v_type != var2.v_type)
			EMSG(_("E735: Can only compare Dictionary with Dictionary"));
		    else
			EMSG(_("E736: Invalid operation for Dictionary"));
		    clear_tv(rettv);
		    clear_tv(&var2);
		    return FAIL;
		}
		else
		{
		    /* Compare two Dictionaries for being equal or unequal. */
		    n1 = dict_equal(rettv->vval.v_dict, var2.vval.v_dict,
								   ic, FALSE);
		    if (type == TYPE_NEQUAL)
			n1 = !n1;
		}
	    }

	    else if (rettv->v_type == VAR_FUNC || var2.v_type == VAR_FUNC
		|| rettv->v_type == VAR_PARTIAL || var2.v_type == VAR_PARTIAL)
	    {
		if (type != TYPE_EQUAL && type != TYPE_NEQUAL)
		{
		    EMSG(_("E694: Invalid operation for Funcrefs"));
		    clear_tv(rettv);
		    clear_tv(&var2);
		    return FAIL;
		}
		if ((rettv->v_type == VAR_PARTIAL
					     && rettv->vval.v_partial == NULL)
			|| (var2.v_type == VAR_PARTIAL
					      && var2.vval.v_partial == NULL))
		    /* when a partial is NULL assume not equal */
		    n1 = FALSE;
		else if (type_is)
		{
		    if (rettv->v_type == VAR_FUNC && var2.v_type == VAR_FUNC)
			/* strings are considered the same if their value is
			 * the same */
			n1 = tv_equal(rettv, &var2, ic, FALSE);
		    else if (rettv->v_type == VAR_PARTIAL
						&& var2.v_type == VAR_PARTIAL)
			n1 = (rettv->vval.v_partial == var2.vval.v_partial);
		    else
			n1 = FALSE;
		}
		else
		    n1 = tv_equal(rettv, &var2, ic, FALSE);
		if (type == TYPE_NEQUAL)
		    n1 = !n1;
	    }

#ifdef FEAT_FLOAT
	    /*
	     * If one of the two variables is a float, compare as a float.
	     * When using "=~" or "!~", always compare as string.
	     */
	    else if ((rettv->v_type == VAR_FLOAT || var2.v_type == VAR_FLOAT)
		    && type != TYPE_MATCH && type != TYPE_NOMATCH)
	    {
		float_T f1, f2;

		if (rettv->v_type == VAR_FLOAT)
		    f1 = rettv->vval.v_float;
		else
		    f1 = get_tv_number(rettv);
		if (var2.v_type == VAR_FLOAT)
		    f2 = var2.vval.v_float;
		else
		    f2 = get_tv_number(&var2);
		n1 = FALSE;
		switch (type)
		{
		    case TYPE_EQUAL:    n1 = (f1 == f2); break;
		    case TYPE_NEQUAL:   n1 = (f1 != f2); break;
		    case TYPE_GREATER:  n1 = (f1 > f2); break;
		    case TYPE_GEQUAL:   n1 = (f1 >= f2); break;
		    case TYPE_SMALLER:  n1 = (f1 < f2); break;
		    case TYPE_SEQUAL:   n1 = (f1 <= f2); break;
		    case TYPE_UNKNOWN:
		    case TYPE_MATCH:
		    case TYPE_NOMATCH:  break;  /* avoid gcc warning */
		}
	    }
#endif

	    /*
	     * If one of the two variables is a number, compare as a number.
	     * When using "=~" or "!~", always compare as string.
	     */
	    else if ((rettv->v_type == VAR_NUMBER || var2.v_type == VAR_NUMBER)
		    && type != TYPE_MATCH && type != TYPE_NOMATCH)
	    {
		n1 = get_tv_number(rettv);
		n2 = get_tv_number(&var2);
		switch (type)
		{
		    case TYPE_EQUAL:    n1 = (n1 == n2); break;
		    case TYPE_NEQUAL:   n1 = (n1 != n2); break;
		    case TYPE_GREATER:  n1 = (n1 > n2); break;
		    case TYPE_GEQUAL:   n1 = (n1 >= n2); break;
		    case TYPE_SMALLER:  n1 = (n1 < n2); break;
		    case TYPE_SEQUAL:   n1 = (n1 <= n2); break;
		    case TYPE_UNKNOWN:
		    case TYPE_MATCH:
		    case TYPE_NOMATCH:  break;  /* avoid gcc warning */
		}
	    }
	    else
	    {
		s1 = get_tv_string_buf(rettv, buf1);
		s2 = get_tv_string_buf(&var2, buf2);
		if (type != TYPE_MATCH && type != TYPE_NOMATCH)
		    i = ic ? MB_STRICMP(s1, s2) : STRCMP(s1, s2);
		else
		    i = 0;
		n1 = FALSE;
		switch (type)
		{
		    case TYPE_EQUAL:    n1 = (i == 0); break;
		    case TYPE_NEQUAL:   n1 = (i != 0); break;
		    case TYPE_GREATER:  n1 = (i > 0); break;
		    case TYPE_GEQUAL:   n1 = (i >= 0); break;
		    case TYPE_SMALLER:  n1 = (i < 0); break;
		    case TYPE_SEQUAL:   n1 = (i <= 0); break;

		    case TYPE_MATCH:
		    case TYPE_NOMATCH:
			    n1 = pattern_match(s2, s1, ic);
			    if (type == TYPE_NOMATCH)
				n1 = !n1;
			    break;

		    case TYPE_UNKNOWN:  break;  /* avoid gcc warning */
		}
	    }
	    clear_tv(rettv);
	    clear_tv(&var2);
	    rettv->v_type = VAR_NUMBER;
	    rettv->vval.v_number = n1;
	}
    }

    return OK;
}

/*
 * Handle fourth level expression:
 *	+	number addition
 *	-	number subtraction
 *	.	string concatenation
 *
 * "arg" must point to the first non-white of the expression.
 * "arg" is advanced to the next non-white after the recognized expression.
 *
 * Return OK or FAIL.
 */
    static int
eval5(char_u **arg, typval_T *rettv, int evaluate)
{
    typval_T	var2;
    typval_T	var3;
    int		op;
    varnumber_T	n1, n2;
#ifdef FEAT_FLOAT
    float_T	f1 = 0, f2 = 0;
#endif
    char_u	*s1, *s2;
    char_u	buf1[NUMBUFLEN], buf2[NUMBUFLEN];
    char_u	*p;

    /*
     * Get the first variable.
     */
    if (eval6(arg, rettv, evaluate, FALSE) == FAIL)
	return FAIL;

    /*
     * Repeat computing, until no '+', '-' or '.' is following.
     */
    for (;;)
    {
	op = **arg;
	if (op != '+' && op != '-' && op != '.')
	    break;

	if ((op != '+' || rettv->v_type != VAR_LIST)
#ifdef FEAT_FLOAT
		&& (op == '.' || rettv->v_type != VAR_FLOAT)
#endif
		)
	{
	    /* For "list + ...", an illegal use of the first operand as
	     * a number cannot be determined before evaluating the 2nd
	     * operand: if this is also a list, all is ok.
	     * For "something . ...", "something - ..." or "non-list + ...",
	     * we know that the first operand needs to be a string or number
	     * without evaluating the 2nd operand.  So check before to avoid
	     * side effects after an error. */
	    if (evaluate && get_tv_string_chk(rettv) == NULL)
	    {
		clear_tv(rettv);
		return FAIL;
	    }
	}

	/*
	 * Get the second variable.
	 */
	*arg = skipwhite(*arg + 1);
	if (eval6(arg, &var2, evaluate, op == '.') == FAIL)
	{
	    clear_tv(rettv);
	    return FAIL;
	}

	if (evaluate)
	{
	    /*
	     * Compute the result.
	     */
	    if (op == '.')
	    {
		s1 = get_tv_string_buf(rettv, buf1);	/* already checked */
		s2 = get_tv_string_buf_chk(&var2, buf2);
		if (s2 == NULL)		/* type error ? */
		{
		    clear_tv(rettv);
		    clear_tv(&var2);
		    return FAIL;
		}
		p = concat_str(s1, s2);
		clear_tv(rettv);
		rettv->v_type = VAR_STRING;
		rettv->vval.v_string = p;
	    }
	    else if (op == '+' && rettv->v_type == VAR_LIST
						   && var2.v_type == VAR_LIST)
	    {
		/* concatenate Lists */
		if (list_concat(rettv->vval.v_list, var2.vval.v_list,
							       &var3) == FAIL)
		{
		    clear_tv(rettv);
		    clear_tv(&var2);
		    return FAIL;
		}
		clear_tv(rettv);
		*rettv = var3;
	    }
	    else
	    {
		int	    error = FALSE;

#ifdef FEAT_FLOAT
		if (rettv->v_type == VAR_FLOAT)
		{
		    f1 = rettv->vval.v_float;
		    n1 = 0;
		}
		else
#endif
		{
		    n1 = get_tv_number_chk(rettv, &error);
		    if (error)
		    {
			/* This can only happen for "list + non-list".  For
			 * "non-list + ..." or "something - ...", we returned
			 * before evaluating the 2nd operand. */
			clear_tv(rettv);
			return FAIL;
		    }
#ifdef FEAT_FLOAT
		    if (var2.v_type == VAR_FLOAT)
			f1 = n1;
#endif
		}
#ifdef FEAT_FLOAT
		if (var2.v_type == VAR_FLOAT)
		{
		    f2 = var2.vval.v_float;
		    n2 = 0;
		}
		else
#endif
		{
		    n2 = get_tv_number_chk(&var2, &error);
		    if (error)
		    {
			clear_tv(rettv);
			clear_tv(&var2);
			return FAIL;
		    }
#ifdef FEAT_FLOAT
		    if (rettv->v_type == VAR_FLOAT)
			f2 = n2;
#endif
		}
		clear_tv(rettv);

#ifdef FEAT_FLOAT
		/* If there is a float on either side the result is a float. */
		if (rettv->v_type == VAR_FLOAT || var2.v_type == VAR_FLOAT)
		{
		    if (op == '+')
			f1 = f1 + f2;
		    else
			f1 = f1 - f2;
		    rettv->v_type = VAR_FLOAT;
		    rettv->vval.v_float = f1;
		}
		else
#endif
		{
		    if (op == '+')
			n1 = n1 + n2;
		    else
			n1 = n1 - n2;
		    rettv->v_type = VAR_NUMBER;
		    rettv->vval.v_number = n1;
		}
	    }
	    clear_tv(&var2);
	}
    }
    return OK;
}

/*
 * Handle fifth level expression:
 *	*	number multiplication
 *	/	number division
 *	%	number modulo
 *
 * "arg" must point to the first non-white of the expression.
 * "arg" is advanced to the next non-white after the recognized expression.
 *
 * Return OK or FAIL.
 */
    static int
eval6(
    char_u	**arg,
    typval_T	*rettv,
    int		evaluate,
    int		want_string)  /* after "." operator */
{
    typval_T	var2;
    int		op;
    varnumber_T	n1, n2;
#ifdef FEAT_FLOAT
    int		use_float = FALSE;
    float_T	f1 = 0, f2;
#endif
    int		error = FALSE;

    /*
     * Get the first variable.
     */
    if (eval7(arg, rettv, evaluate, want_string) == FAIL)
	return FAIL;

    /*
     * Repeat computing, until no '*', '/' or '%' is following.
     */
    for (;;)
    {
	op = **arg;
	if (op != '*' && op != '/' && op != '%')
	    break;

	if (evaluate)
	{
#ifdef FEAT_FLOAT
	    if (rettv->v_type == VAR_FLOAT)
	    {
		f1 = rettv->vval.v_float;
		use_float = TRUE;
		n1 = 0;
	    }
	    else
#endif
		n1 = get_tv_number_chk(rettv, &error);
	    clear_tv(rettv);
	    if (error)
		return FAIL;
	}
	else
	    n1 = 0;

	/*
	 * Get the second variable.
	 */
	*arg = skipwhite(*arg + 1);
	if (eval7(arg, &var2, evaluate, FALSE) == FAIL)
	    return FAIL;

	if (evaluate)
	{
#ifdef FEAT_FLOAT
	    if (var2.v_type == VAR_FLOAT)
	    {
		if (!use_float)
		{
		    f1 = n1;
		    use_float = TRUE;
		}
		f2 = var2.vval.v_float;
		n2 = 0;
	    }
	    else
#endif
	    {
		n2 = get_tv_number_chk(&var2, &error);
		clear_tv(&var2);
		if (error)
		    return FAIL;
#ifdef FEAT_FLOAT
		if (use_float)
		    f2 = n2;
#endif
	    }

	    /*
	     * Compute the result.
	     * When either side is a float the result is a float.
	     */
#ifdef FEAT_FLOAT
	    if (use_float)
	    {
		if (op == '*')
		    f1 = f1 * f2;
		else if (op == '/')
		{
# ifdef VMS
		    /* VMS crashes on divide by zero, work around it */
		    if (f2 == 0.0)
		    {
			if (f1 == 0)
			    f1 = -1 * __F_FLT_MAX - 1L;   /* similar to NaN */
			else if (f1 < 0)
			    f1 = -1 * __F_FLT_MAX;
			else
			    f1 = __F_FLT_MAX;
		    }
		    else
			f1 = f1 / f2;
# else
		    /* We rely on the floating point library to handle divide
		     * by zero to result in "inf" and not a crash. */
		    f1 = f1 / f2;
# endif
		}
		else
		{
		    EMSG(_("E804: Cannot use '%' with Float"));
		    return FAIL;
		}
		rettv->v_type = VAR_FLOAT;
		rettv->vval.v_float = f1;
	    }
	    else
#endif
	    {
		if (op == '*')
		    n1 = n1 * n2;
		else if (op == '/')
		{
		    if (n2 == 0)	/* give an error message? */
		    {
			if (n1 == 0)
			    n1 = VARNUM_MIN; /* similar to NaN */
			else if (n1 < 0)
			    n1 = -VARNUM_MAX;
			else
			    n1 = VARNUM_MAX;
		    }
		    else
			n1 = n1 / n2;
		}
		else
		{
		    if (n2 == 0)	/* give an error message? */
			n1 = 0;
		    else
			n1 = n1 % n2;
		}
		rettv->v_type = VAR_NUMBER;
		rettv->vval.v_number = n1;
	    }
	}
    }

    return OK;
}

/*
 * Handle sixth level expression:
 *  number		number constant
 *  "string"		string constant
 *  'string'		literal string constant
 *  &option-name	option value
 *  @r			register contents
 *  identifier		variable value
 *  function()		function call
 *  $VAR		environment variable
 *  (expression)	nested expression
 *  [expr, expr]	List
 *  {key: val, key: val}  Dictionary
 *
 *  Also handle:
 *  ! in front		logical NOT
 *  - in front		unary minus
 *  + in front		unary plus (ignored)
 *  trailing []		subscript in String or List
 *  trailing .name	entry in Dictionary
 *
 * "arg" must point to the first non-white of the expression.
 * "arg" is advanced to the next non-white after the recognized expression.
 *
 * Return OK or FAIL.
 */
    static int
eval7(
    char_u	**arg,
    typval_T	*rettv,
    int		evaluate,
    int		want_string UNUSED)	/* after "." operator */
{
    varnumber_T	n;
    int		len;
    char_u	*s;
    char_u	*start_leader, *end_leader;
    int		ret = OK;
    char_u	*alias;

    /*
     * Initialise variable so that clear_tv() can't mistake this for a
     * string and free a string that isn't there.
     */
    rettv->v_type = VAR_UNKNOWN;

    /*
     * Skip '!', '-' and '+' characters.  They are handled later.
     */
    start_leader = *arg;
    while (**arg == '!' || **arg == '-' || **arg == '+')
	*arg = skipwhite(*arg + 1);
    end_leader = *arg;

    switch (**arg)
    {
    /*
     * Number constant.
     */
    case '0':
    case '1':
    case '2':
    case '3':
    case '4':
    case '5':
    case '6':
    case '7':
    case '8':
    case '9':
	{
#ifdef FEAT_FLOAT
		char_u *p = skipdigits(*arg + 1);
		int    get_float = FALSE;

		/* We accept a float when the format matches
		 * "[0-9]\+\.[0-9]\+\([eE][+-]\?[0-9]\+\)\?".  This is very
		 * strict to avoid backwards compatibility problems.
		 * Don't look for a float after the "." operator, so that
		 * ":let vers = 1.2.3" doesn't fail. */
		if (!want_string && p[0] == '.' && vim_isdigit(p[1]))
		{
		    get_float = TRUE;
		    p = skipdigits(p + 2);
		    if (*p == 'e' || *p == 'E')
		    {
			++p;
			if (*p == '-' || *p == '+')
			    ++p;
			if (!vim_isdigit(*p))
			    get_float = FALSE;
			else
			    p = skipdigits(p + 1);
		    }
		    if (ASCII_ISALPHA(*p) || *p == '.')
			get_float = FALSE;
		}
		if (get_float)
		{
		    float_T	f;

		    *arg += string2float(*arg, &f);
		    if (evaluate)
		    {
			rettv->v_type = VAR_FLOAT;
			rettv->vval.v_float = f;
		    }
		}
		else
#endif
		{
		    vim_str2nr(*arg, NULL, &len, STR2NR_ALL, &n, NULL, 0);
		    *arg += len;
		    if (evaluate)
		    {
			rettv->v_type = VAR_NUMBER;
			rettv->vval.v_number = n;
		    }
		}
		break;
	}

    /*
     * String constant: "string".
     */
    case '"':	ret = get_string_tv(arg, rettv, evaluate);
		break;

    /*
     * Literal string constant: 'str''ing'.
     */
    case '\'':	ret = get_lit_string_tv(arg, rettv, evaluate);
		break;

    /*
     * List: [expr, expr]
     */
    case '[':	ret = get_list_tv(arg, rettv, evaluate);
		break;

    /*
     * Lambda: {arg, arg -> expr}
     * Dictionary: {key: val, key: val}
     */
    case '{':	ret = get_lambda_tv(arg, rettv, evaluate);
		if (ret == NOTDONE)
		    ret = get_dict_tv(arg, rettv, evaluate);
		break;

    /*
     * Option value: &name
     */
    case '&':	ret = get_option_tv(arg, rettv, evaluate);
		break;

    /*
     * Environment variable: $VAR.
     */
    case '$':	ret = get_env_tv(arg, rettv, evaluate);
		break;

    /*
     * Register contents: @r.
     */
    case '@':	++*arg;
		if (evaluate)
		{
		    rettv->v_type = VAR_STRING;
		    rettv->vval.v_string = get_reg_contents(**arg,
							    GREG_EXPR_SRC);
		}
		if (**arg != NUL)
		    ++*arg;
		break;

    /*
     * nested expression: (expression).
     */
    case '(':	*arg = skipwhite(*arg + 1);
		ret = eval1(arg, rettv, evaluate);	/* recursive! */
		if (**arg == ')')
		    ++*arg;
		else if (ret == OK)
		{
		    EMSG(_("E110: Missing ')'"));
		    clear_tv(rettv);
		    ret = FAIL;
		}
		break;

    default:	ret = NOTDONE;
		break;
    }

    if (ret == NOTDONE)
    {
	/*
	 * Must be a variable or function name.
	 * Can also be a curly-braces kind of name: {expr}.
	 */
	s = *arg;
	len = get_name_len(arg, &alias, evaluate, TRUE);
	if (alias != NULL)
	    s = alias;

	if (len <= 0)
	    ret = FAIL;
	else
	{
	    if (**arg == '(')		/* recursive! */
	    {
		partial_T *partial;

		if (!evaluate)
		    check_vars(s, len);

		/* If "s" is the name of a variable of type VAR_FUNC
		 * use its contents. */
		s = deref_func_name(s, &len, &partial, !evaluate);

		/* Need to make a copy, in case evaluating the arguments makes
		 * the name invalid. */
		s = vim_strsave(s);
		if (s == NULL)
		    ret = FAIL;
		else
		    /* Invoke the function. */
		    ret = get_func_tv(s, len, rettv, arg,
			      curwin->w_cursor.lnum, curwin->w_cursor.lnum,
			      &len, evaluate, partial, NULL);
		vim_free(s);

		/* If evaluate is FALSE rettv->v_type was not set in
		 * get_func_tv, but it's needed in handle_subscript() to parse
		 * what follows. So set it here. */
		if (rettv->v_type == VAR_UNKNOWN && !evaluate && **arg == '(')
		{
		    rettv->vval.v_string = NULL;
		    rettv->v_type = VAR_FUNC;
		}

		/* Stop the expression evaluation when immediately
		 * aborting on error, or when an interrupt occurred or
		 * an exception was thrown but not caught. */
		if (aborting())
		{
		    if (ret == OK)
			clear_tv(rettv);
		    ret = FAIL;
		}
	    }
	    else if (evaluate)
		ret = get_var_tv(s, len, rettv, NULL, TRUE, FALSE);
	    else
	    {
		check_vars(s, len);
		ret = OK;
	    }
	}
	vim_free(alias);
    }

    *arg = skipwhite(*arg);

    /* Handle following '[', '(' and '.' for expr[expr], expr.name,
     * expr(expr). */
    if (ret == OK)
	ret = handle_subscript(arg, rettv, evaluate, TRUE);

    /*
     * Apply logical NOT and unary '-', from right to left, ignore '+'.
     */
    if (ret == OK && evaluate && end_leader > start_leader)
    {
	int	    error = FALSE;
	varnumber_T val = 0;
#ifdef FEAT_FLOAT
	float_T	    f = 0.0;

	if (rettv->v_type == VAR_FLOAT)
	    f = rettv->vval.v_float;
	else
#endif
	    val = get_tv_number_chk(rettv, &error);
	if (error)
	{
	    clear_tv(rettv);
	    ret = FAIL;
	}
	else
	{
	    while (end_leader > start_leader)
	    {
		--end_leader;
		if (*end_leader == '!')
		{
#ifdef FEAT_FLOAT
		    if (rettv->v_type == VAR_FLOAT)
			f = !f;
		    else
#endif
			val = !val;
		}
		else if (*end_leader == '-')
		{
#ifdef FEAT_FLOAT
		    if (rettv->v_type == VAR_FLOAT)
			f = -f;
		    else
#endif
			val = -val;
		}
	    }
#ifdef FEAT_FLOAT
	    if (rettv->v_type == VAR_FLOAT)
	    {
		clear_tv(rettv);
		rettv->vval.v_float = f;
	    }
	    else
#endif
	    {
		clear_tv(rettv);
		rettv->v_type = VAR_NUMBER;
		rettv->vval.v_number = val;
	    }
	}
    }

    return ret;
}

/*
 * Evaluate an "[expr]" or "[expr:expr]" index.  Also "dict.key".
 * "*arg" points to the '[' or '.'.
 * Returns FAIL or OK. "*arg" is advanced to after the ']'.
 */
    static int
eval_index(
    char_u	**arg,
    typval_T	*rettv,
    int		evaluate,
    int		verbose)	/* give error messages */
{
    int		empty1 = FALSE, empty2 = FALSE;
    typval_T	var1, var2;
    long	n1, n2 = 0;
    long	len = -1;
    int		range = FALSE;
    char_u	*s;
    char_u	*key = NULL;

    switch (rettv->v_type)
    {
	case VAR_FUNC:
	case VAR_PARTIAL:
	    if (verbose)
		EMSG(_("E695: Cannot index a Funcref"));
	    return FAIL;
	case VAR_FLOAT:
#ifdef FEAT_FLOAT
	    if (verbose)
		EMSG(_(e_float_as_string));
	    return FAIL;
#endif
	case VAR_SPECIAL:
	case VAR_JOB:
	case VAR_CHANNEL:
	    if (verbose)
		EMSG(_("E909: Cannot index a special variable"));
	    return FAIL;
	case VAR_UNKNOWN:
	    if (evaluate)
		return FAIL;
	    /* FALLTHROUGH */

	case VAR_STRING:
	case VAR_NUMBER:
	case VAR_LIST:
	case VAR_DICT:
	    break;
    }

    init_tv(&var1);
    init_tv(&var2);
    if (**arg == '.')
    {
	/*
	 * dict.name
	 */
	key = *arg + 1;
	for (len = 0; ASCII_ISALNUM(key[len]) || key[len] == '_'; ++len)
	    ;
	if (len == 0)
	    return FAIL;
	*arg = skipwhite(key + len);
    }
    else
    {
	/*
	 * something[idx]
	 *
	 * Get the (first) variable from inside the [].
	 */
	*arg = skipwhite(*arg + 1);
	if (**arg == ':')
	    empty1 = TRUE;
	else if (eval1(arg, &var1, evaluate) == FAIL)	/* recursive! */
	    return FAIL;
	else if (evaluate && get_tv_string_chk(&var1) == NULL)
	{
	    /* not a number or string */
	    clear_tv(&var1);
	    return FAIL;
	}

	/*
	 * Get the second variable from inside the [:].
	 */
	if (**arg == ':')
	{
	    range = TRUE;
	    *arg = skipwhite(*arg + 1);
	    if (**arg == ']')
		empty2 = TRUE;
	    else if (eval1(arg, &var2, evaluate) == FAIL)	/* recursive! */
	    {
		if (!empty1)
		    clear_tv(&var1);
		return FAIL;
	    }
	    else if (evaluate && get_tv_string_chk(&var2) == NULL)
	    {
		/* not a number or string */
		if (!empty1)
		    clear_tv(&var1);
		clear_tv(&var2);
		return FAIL;
	    }
	}

	/* Check for the ']'. */
	if (**arg != ']')
	{
	    if (verbose)
		EMSG(_(e_missbrac));
	    clear_tv(&var1);
	    if (range)
		clear_tv(&var2);
	    return FAIL;
	}
	*arg = skipwhite(*arg + 1);	/* skip the ']' */
    }

    if (evaluate)
    {
	n1 = 0;
	if (!empty1 && rettv->v_type != VAR_DICT)
	{
	    n1 = get_tv_number(&var1);
	    clear_tv(&var1);
	}
	if (range)
	{
	    if (empty2)
		n2 = -1;
	    else
	    {
		n2 = get_tv_number(&var2);
		clear_tv(&var2);
	    }
	}

	switch (rettv->v_type)
	{
	    case VAR_UNKNOWN:
	    case VAR_FUNC:
	    case VAR_PARTIAL:
	    case VAR_FLOAT:
	    case VAR_SPECIAL:
	    case VAR_JOB:
	    case VAR_CHANNEL:
		break; /* not evaluating, skipping over subscript */

	    case VAR_NUMBER:
	    case VAR_STRING:
		s = get_tv_string(rettv);
		len = (long)STRLEN(s);
		if (range)
		{
		    /* The resulting variable is a substring.  If the indexes
		     * are out of range the result is empty. */
		    if (n1 < 0)
		    {
			n1 = len + n1;
			if (n1 < 0)
			    n1 = 0;
		    }
		    if (n2 < 0)
			n2 = len + n2;
		    else if (n2 >= len)
			n2 = len;
		    if (n1 >= len || n2 < 0 || n1 > n2)
			s = NULL;
		    else
			s = vim_strnsave(s + n1, (int)(n2 - n1 + 1));
		}
		else
		{
		    /* The resulting variable is a string of a single
		     * character.  If the index is too big or negative the
		     * result is empty. */
		    if (n1 >= len || n1 < 0)
			s = NULL;
		    else
			s = vim_strnsave(s + n1, 1);
		}
		clear_tv(rettv);
		rettv->v_type = VAR_STRING;
		rettv->vval.v_string = s;
		break;

	    case VAR_LIST:
		len = list_len(rettv->vval.v_list);
		if (n1 < 0)
		    n1 = len + n1;
		if (!empty1 && (n1 < 0 || n1 >= len))
		{
		    /* For a range we allow invalid values and return an empty
		     * list.  A list index out of range is an error. */
		    if (!range)
		    {
			if (verbose)
			    EMSGN(_(e_listidx), n1);
			return FAIL;
		    }
		    n1 = len;
		}
		if (range)
		{
		    list_T	*l;
		    listitem_T	*item;

		    if (n2 < 0)
			n2 = len + n2;
		    else if (n2 >= len)
			n2 = len - 1;
		    if (!empty2 && (n2 < 0 || n2 + 1 < n1))
			n2 = -1;
		    l = list_alloc();
		    if (l == NULL)
			return FAIL;
		    for (item = list_find(rettv->vval.v_list, n1);
							       n1 <= n2; ++n1)
		    {
			if (list_append_tv(l, &item->li_tv) == FAIL)
			{
			    list_free(l);
			    return FAIL;
			}
			item = item->li_next;
		    }
		    clear_tv(rettv);
		    rettv_list_set(rettv, l);
		}
		else
		{
		    copy_tv(&list_find(rettv->vval.v_list, n1)->li_tv, &var1);
		    clear_tv(rettv);
		    *rettv = var1;
		}
		break;

	    case VAR_DICT:
		if (range)
		{
		    if (verbose)
			EMSG(_(e_dictrange));
		    if (len == -1)
			clear_tv(&var1);
		    return FAIL;
		}
		{
		    dictitem_T	*item;

		    if (len == -1)
		    {
			key = get_tv_string_chk(&var1);
			if (key == NULL)
			{
			    clear_tv(&var1);
			    return FAIL;
			}
		    }

		    item = dict_find(rettv->vval.v_dict, key, (int)len);

		    if (item == NULL && verbose)
			EMSG2(_(e_dictkey), key);
		    if (len == -1)
			clear_tv(&var1);
		    if (item == NULL)
			return FAIL;

		    copy_tv(&item->di_tv, &var1);
		    clear_tv(rettv);
		    *rettv = var1;
		}
		break;
	}
    }

    return OK;
}

/*
 * Get an option value.
 * "arg" points to the '&' or '+' before the option name.
 * "arg" is advanced to character after the option name.
 * Return OK or FAIL.
 */
    int
get_option_tv(
    char_u	**arg,
    typval_T	*rettv,	/* when NULL, only check if option exists */
    int		evaluate)
{
    char_u	*option_end;
    long	numval;
    char_u	*stringval;
    int		opt_type;
    int		c;
    int		working = (**arg == '+');    /* has("+option") */
    int		ret = OK;
    int		opt_flags;

    /*
     * Isolate the option name and find its value.
     */
    option_end = find_option_end(arg, &opt_flags);
    if (option_end == NULL)
    {
	if (rettv != NULL)
	    EMSG2(_("E112: Option name missing: %s"), *arg);
	return FAIL;
    }

    if (!evaluate)
    {
	*arg = option_end;
	return OK;
    }

    c = *option_end;
    *option_end = NUL;
    opt_type = get_option_value(*arg, &numval,
			       rettv == NULL ? NULL : &stringval, opt_flags);

    if (opt_type == -3)			/* invalid name */
    {
	if (rettv != NULL)
	    EMSG2(_("E113: Unknown option: %s"), *arg);
	ret = FAIL;
    }
    else if (rettv != NULL)
    {
	if (opt_type == -2)		/* hidden string option */
	{
	    rettv->v_type = VAR_STRING;
	    rettv->vval.v_string = NULL;
	}
	else if (opt_type == -1)	/* hidden number option */
	{
	    rettv->v_type = VAR_NUMBER;
	    rettv->vval.v_number = 0;
	}
	else if (opt_type == 1)		/* number option */
	{
	    rettv->v_type = VAR_NUMBER;
	    rettv->vval.v_number = numval;
	}
	else				/* string option */
	{
	    rettv->v_type = VAR_STRING;
	    rettv->vval.v_string = stringval;
	}
    }
    else if (working && (opt_type == -2 || opt_type == -1))
	ret = FAIL;

    *option_end = c;		    /* put back for error messages */
    *arg = option_end;

    return ret;
}

/*
 * Allocate a variable for a string constant.
 * Return OK or FAIL.
 */
    static int
get_string_tv(char_u **arg, typval_T *rettv, int evaluate)
{
    char_u	*p;
    char_u	*name;
    int		extra = 0;

    /*
     * Find the end of the string, skipping backslashed characters.
     */
    for (p = *arg + 1; *p != NUL && *p != '"'; MB_PTR_ADV(p))
    {
	if (*p == '\\' && p[1] != NUL)
	{
	    ++p;
	    /* A "\<x>" form occupies at least 4 characters, and produces up
	     * to 6 characters: reserve space for 2 extra */
	    if (*p == '<')
		extra += 2;
	}
    }

    if (*p != '"')
    {
	EMSG2(_("E114: Missing quote: %s"), *arg);
	return FAIL;
    }

    /* If only parsing, set *arg and return here */
    if (!evaluate)
    {
	*arg = p + 1;
	return OK;
    }

    /*
     * Copy the string into allocated memory, handling backslashed
     * characters.
     */
    name = alloc((unsigned)(p - *arg + extra));
    if (name == NULL)
	return FAIL;
    rettv->v_type = VAR_STRING;
    rettv->vval.v_string = name;

    for (p = *arg + 1; *p != NUL && *p != '"'; )
    {
	if (*p == '\\')
	{
	    switch (*++p)
	    {
		case 'b': *name++ = BS; ++p; break;
		case 'e': *name++ = ESC; ++p; break;
		case 'f': *name++ = FF; ++p; break;
		case 'n': *name++ = NL; ++p; break;
		case 'r': *name++ = CAR; ++p; break;
		case 't': *name++ = TAB; ++p; break;

		case 'X': /* hex: "\x1", "\x12" */
		case 'x':
		case 'u': /* Unicode: "\u0023" */
		case 'U':
			  if (vim_isxdigit(p[1]))
			  {
			      int	n, nr;
			      int	c = toupper(*p);

			      if (c == 'X')
				  n = 2;
			      else if (*p == 'u')
				  n = 4;
			      else
				  n = 8;
			      nr = 0;
			      while (--n >= 0 && vim_isxdigit(p[1]))
			      {
				  ++p;
				  nr = (nr << 4) + hex2nr(*p);
			      }
			      ++p;
#ifdef FEAT_MBYTE
			      /* For "\u" store the number according to
			       * 'encoding'. */
			      if (c != 'X')
				  name += (*mb_char2bytes)(nr, name);
			      else
#endif
				  *name++ = nr;
			  }
			  break;

			  /* octal: "\1", "\12", "\123" */
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7': *name = *p++ - '0';
			  if (*p >= '0' && *p <= '7')
			  {
			      *name = (*name << 3) + *p++ - '0';
			      if (*p >= '0' && *p <= '7')
				  *name = (*name << 3) + *p++ - '0';
			  }
			  ++name;
			  break;

			    /* Special key, e.g.: "\<C-W>" */
		case '<': extra = trans_special(&p, name, TRUE, TRUE);
			  if (extra != 0)
			  {
			      name += extra;
			      break;
			  }
			  /* FALLTHROUGH */

		default:  MB_COPY_CHAR(p, name);
			  break;
	    }
	}
	else
	    MB_COPY_CHAR(p, name);

    }
    *name = NUL;
    if (*p != NUL) /* just in case */
	++p;
    *arg = p;

    return OK;
}

/*
 * Allocate a variable for a 'str''ing' constant.
 * Return OK or FAIL.
 */
    static int
get_lit_string_tv(char_u **arg, typval_T *rettv, int evaluate)
{
    char_u	*p;
    char_u	*str;
    int		reduce = 0;

    /*
     * Find the end of the string, skipping ''.
     */
    for (p = *arg + 1; *p != NUL; MB_PTR_ADV(p))
    {
	if (*p == '\'')
	{
	    if (p[1] != '\'')
		break;
	    ++reduce;
	    ++p;
	}
    }

    if (*p != '\'')
    {
	EMSG2(_("E115: Missing quote: %s"), *arg);
	return FAIL;
    }

    /* If only parsing return after setting "*arg" */
    if (!evaluate)
    {
	*arg = p + 1;
	return OK;
    }

    /*
     * Copy the string into allocated memory, handling '' to ' reduction.
     */
    str = alloc((unsigned)((p - *arg) - reduce));
    if (str == NULL)
	return FAIL;
    rettv->v_type = VAR_STRING;
    rettv->vval.v_string = str;

    for (p = *arg + 1; *p != NUL; )
    {
	if (*p == '\'')
	{
	    if (p[1] != '\'')
		break;
	    ++p;
	}
	MB_COPY_CHAR(p, str);
    }
    *str = NUL;
    *arg = p + 1;

    return OK;
}

/*
 * Return the function name of the partial.
 */
    char_u *
partial_name(partial_T *pt)
{
    if (pt->pt_name != NULL)
	return pt->pt_name;
    return pt->pt_func->uf_name;
}

    static void
partial_free(partial_T *pt)
{
    int i;

    for (i = 0; i < pt->pt_argc; ++i)
	clear_tv(&pt->pt_argv[i]);
    vim_free(pt->pt_argv);
    dict_unref(pt->pt_dict);
    if (pt->pt_name != NULL)
    {
	func_unref(pt->pt_name);
	vim_free(pt->pt_name);
    }
    else
	func_ptr_unref(pt->pt_func);
    vim_free(pt);
}

/*
 * Unreference a closure: decrement the reference count and free it when it
 * becomes zero.
 */
    void
partial_unref(partial_T *pt)
{
    if (pt != NULL && --pt->pt_refcount <= 0)
	partial_free(pt);
}

static int tv_equal_recurse_limit;

    static int
func_equal(
    typval_T *tv1,
    typval_T *tv2,
    int	     ic)	    /* ignore case */
{
    char_u	*s1, *s2;
    dict_T	*d1, *d2;
    int		a1, a2;
    int		i;

    /* empty and NULL function name considered the same */
    s1 = tv1->v_type == VAR_FUNC ? tv1->vval.v_string
					   : partial_name(tv1->vval.v_partial);
    if (s1 != NULL && *s1 == NUL)
	s1 = NULL;
    s2 = tv2->v_type == VAR_FUNC ? tv2->vval.v_string
					   : partial_name(tv2->vval.v_partial);
    if (s2 != NULL && *s2 == NUL)
	s2 = NULL;
    if (s1 == NULL || s2 == NULL)
    {
	if (s1 != s2)
	    return FALSE;
    }
    else if (STRCMP(s1, s2) != 0)
	return FALSE;

    /* empty dict and NULL dict is different */
    d1 = tv1->v_type == VAR_FUNC ? NULL : tv1->vval.v_partial->pt_dict;
    d2 = tv2->v_type == VAR_FUNC ? NULL : tv2->vval.v_partial->pt_dict;
    if (d1 == NULL || d2 == NULL)
    {
	if (d1 != d2)
	    return FALSE;
    }
    else if (!dict_equal(d1, d2, ic, TRUE))
	return FALSE;

    /* empty list and no list considered the same */
    a1 = tv1->v_type == VAR_FUNC ? 0 : tv1->vval.v_partial->pt_argc;
    a2 = tv2->v_type == VAR_FUNC ? 0 : tv2->vval.v_partial->pt_argc;
    if (a1 != a2)
	return FALSE;
    for (i = 0; i < a1; ++i)
	if (!tv_equal(tv1->vval.v_partial->pt_argv + i,
		      tv2->vval.v_partial->pt_argv + i, ic, TRUE))
	    return FALSE;

    return TRUE;
}

/*
 * Return TRUE if "tv1" and "tv2" have the same value.
 * Compares the items just like "==" would compare them, but strings and
 * numbers are different.  Floats and numbers are also different.
 */
    int
tv_equal(
    typval_T *tv1,
    typval_T *tv2,
    int	     ic,	    /* ignore case */
    int	     recursive)	    /* TRUE when used recursively */
{
    char_u	buf1[NUMBUFLEN], buf2[NUMBUFLEN];
    char_u	*s1, *s2;
    static int  recursive_cnt = 0;	    /* catch recursive loops */
    int		r;

    /* Catch lists and dicts that have an endless loop by limiting
     * recursiveness to a limit.  We guess they are equal then.
     * A fixed limit has the problem of still taking an awful long time.
     * Reduce the limit every time running into it. That should work fine for
     * deeply linked structures that are not recursively linked and catch
     * recursiveness quickly. */
    if (!recursive)
	tv_equal_recurse_limit = 1000;
    if (recursive_cnt >= tv_equal_recurse_limit)
    {
	--tv_equal_recurse_limit;
	return TRUE;
    }

    /* For VAR_FUNC and VAR_PARTIAL compare the function name, bound dict and
     * arguments. */
    if ((tv1->v_type == VAR_FUNC
		|| (tv1->v_type == VAR_PARTIAL && tv1->vval.v_partial != NULL))
	    && (tv2->v_type == VAR_FUNC
		|| (tv2->v_type == VAR_PARTIAL && tv2->vval.v_partial != NULL)))
    {
	++recursive_cnt;
	r = func_equal(tv1, tv2, ic);
	--recursive_cnt;
	return r;
    }

    if (tv1->v_type != tv2->v_type)
	return FALSE;

    switch (tv1->v_type)
    {
	case VAR_LIST:
	    ++recursive_cnt;
	    r = list_equal(tv1->vval.v_list, tv2->vval.v_list, ic, TRUE);
	    --recursive_cnt;
	    return r;

	case VAR_DICT:
	    ++recursive_cnt;
	    r = dict_equal(tv1->vval.v_dict, tv2->vval.v_dict, ic, TRUE);
	    --recursive_cnt;
	    return r;

	case VAR_NUMBER:
	    return tv1->vval.v_number == tv2->vval.v_number;

	case VAR_STRING:
	    s1 = get_tv_string_buf(tv1, buf1);
	    s2 = get_tv_string_buf(tv2, buf2);
	    return ((ic ? MB_STRICMP(s1, s2) : STRCMP(s1, s2)) == 0);

	case VAR_SPECIAL:
	    return tv1->vval.v_number == tv2->vval.v_number;

	case VAR_FLOAT:
#ifdef FEAT_FLOAT
	    return tv1->vval.v_float == tv2->vval.v_float;
#endif
	case VAR_JOB:
#ifdef FEAT_JOB_CHANNEL
	    return tv1->vval.v_job == tv2->vval.v_job;
#endif
	case VAR_CHANNEL:
#ifdef FEAT_JOB_CHANNEL
	    return tv1->vval.v_channel == tv2->vval.v_channel;
#endif
	case VAR_FUNC:
	case VAR_PARTIAL:
	case VAR_UNKNOWN:
	    break;
    }

    /* VAR_UNKNOWN can be the result of a invalid expression, let's say it
     * does not equal anything, not even itself. */
    return FALSE;
}

/*
 * Return the next (unique) copy ID.
 * Used for serializing nested structures.
 */
    int
get_copyID(void)
{
    current_copyID += COPYID_INC;
    return current_copyID;
}

/*
 * Garbage collection for lists and dictionaries.
 *
 * We use reference counts to be able to free most items right away when they
 * are no longer used.  But for composite items it's possible that it becomes
 * unused while the reference count is > 0: When there is a recursive
 * reference.  Example:
 *	:let l = [1, 2, 3]
 *	:let d = {9: l}
 *	:let l[1] = d
 *
 * Since this is quite unusual we handle this with garbage collection: every
 * once in a while find out which lists and dicts are not referenced from any
 * variable.
 *
 * Here is a good reference text about garbage collection (refers to Python
 * but it applies to all reference-counting mechanisms):
 *	http://python.ca/nas/python/gc/
 */

/*
 * Do garbage collection for lists and dicts.
 * When "testing" is TRUE this is called from test_garbagecollect_now().
 * Return TRUE if some memory was freed.
 */
    int
garbage_collect(int testing)
{
    int		copyID;
    int		abort = FALSE;
    buf_T	*buf;
    win_T	*wp;
    int		i;
    int		did_free = FALSE;
    tabpage_T	*tp;

    if (!testing)
    {
	/* Only do this once. */
	want_garbage_collect = FALSE;
	may_garbage_collect = FALSE;
	garbage_collect_at_exit = FALSE;
    }

    /* We advance by two because we add one for items referenced through
     * previous_funccal. */
    copyID = get_copyID();

    /*
     * 1. Go through all accessible variables and mark all lists and dicts
     *    with copyID.
     */

    /* Don't free variables in the previous_funccal list unless they are only
     * referenced through previous_funccal.  This must be first, because if
     * the item is referenced elsewhere the funccal must not be freed. */
    abort = abort || set_ref_in_previous_funccal(copyID);

    /* script-local variables */
    for (i = 1; i <= ga_scripts.ga_len; ++i)
	abort = abort || set_ref_in_ht(&SCRIPT_VARS(i), copyID, NULL);

    /* buffer-local variables */
    FOR_ALL_BUFFERS(buf)
	abort = abort || set_ref_in_item(&buf->b_bufvar.di_tv, copyID,
								  NULL, NULL);

    /* window-local variables */
    FOR_ALL_TAB_WINDOWS(tp, wp)
	abort = abort || set_ref_in_item(&wp->w_winvar.di_tv, copyID,
								  NULL, NULL);
#ifdef FEAT_AUTOCMD
    if (aucmd_win != NULL)
	abort = abort || set_ref_in_item(&aucmd_win->w_winvar.di_tv, copyID,
								  NULL, NULL);
#endif

    /* tabpage-local variables */
    FOR_ALL_TABPAGES(tp)
	abort = abort || set_ref_in_item(&tp->tp_winvar.di_tv, copyID,
								  NULL, NULL);
    /* global variables */
    abort = abort || set_ref_in_ht(&globvarht, copyID, NULL);

    /* function-local variables */
    abort = abort || set_ref_in_call_stack(copyID);

    /* named functions (matters for closures) */
    abort = abort || set_ref_in_functions(copyID);

    /* function call arguments, if v:testing is set. */
    abort = abort || set_ref_in_func_args(copyID);

    /* v: vars */
    abort = abort || set_ref_in_ht(&vimvarht, copyID, NULL);

#ifdef FEAT_LUA
    abort = abort || set_ref_in_lua(copyID);
#endif

#ifdef FEAT_PYTHON
    abort = abort || set_ref_in_python(copyID);
#endif

#ifdef FEAT_PYTHON3
    abort = abort || set_ref_in_python3(copyID);
#endif

#ifdef FEAT_JOB_CHANNEL
    abort = abort || set_ref_in_channel(copyID);
    abort = abort || set_ref_in_job(copyID);
#endif
#ifdef FEAT_NETBEANS_INTG
    abort = abort || set_ref_in_nb_channel(copyID);
#endif

#ifdef FEAT_TIMERS
    abort = abort || set_ref_in_timer(copyID);
#endif

#ifdef FEAT_QUICKFIX
    abort = abort || set_ref_in_quickfix(copyID);
#endif

#ifdef FEAT_TERMINAL
    abort = abort || set_ref_in_term(copyID);
#endif

    if (!abort)
    {
	/*
	 * 2. Free lists and dictionaries that are not referenced.
	 */
	did_free = free_unref_items(copyID);

	/*
	 * 3. Check if any funccal can be freed now.
	 *    This may call us back recursively.
	 */
	free_unref_funccal(copyID, testing);
    }
    else if (p_verbose > 0)
    {
	verb_msg((char_u *)_("Not enough memory to set references, garbage collection aborted!"));
    }

    return did_free;
}

/*
 * Free lists, dictionaries, channels and jobs that are no longer referenced.
 */
    static int
free_unref_items(int copyID)
{
    int		did_free = FALSE;

    /* Let all "free" functions know that we are here.  This means no
     * dictionaries, lists, channels or jobs are to be freed, because we will
     * do that here. */
    in_free_unref_items = TRUE;

    /*
     * PASS 1: free the contents of the items.  We don't free the items
     * themselves yet, so that it is possible to decrement refcount counters
     */

    /* Go through the list of dicts and free items without the copyID. */
    did_free |= dict_free_nonref(copyID);

    /* Go through the list of lists and free items without the copyID. */
    did_free |= list_free_nonref(copyID);

#ifdef FEAT_JOB_CHANNEL
    /* Go through the list of jobs and free items without the copyID. This
     * must happen before doing channels, because jobs refer to channels, but
     * the reference from the channel to the job isn't tracked. */
    did_free |= free_unused_jobs_contents(copyID, COPYID_MASK);

    /* Go through the list of channels and free items without the copyID.  */
    did_free |= free_unused_channels_contents(copyID, COPYID_MASK);
#endif

    /*
     * PASS 2: free the items themselves.
     */
    dict_free_items(copyID);
    list_free_items(copyID);

#ifdef FEAT_JOB_CHANNEL
    /* Go through the list of jobs and free items without the copyID. This
     * must happen before doing channels, because jobs refer to channels, but
     * the reference from the channel to the job isn't tracked. */
    free_unused_jobs(copyID, COPYID_MASK);

    /* Go through the list of channels and free items without the copyID.  */
    free_unused_channels(copyID, COPYID_MASK);
#endif

    in_free_unref_items = FALSE;

    return did_free;
}

/*
 * Mark all lists and dicts referenced through hashtab "ht" with "copyID".
 * "list_stack" is used to add lists to be marked.  Can be NULL.
 *
 * Returns TRUE if setting references failed somehow.
 */
    int
set_ref_in_ht(hashtab_T *ht, int copyID, list_stack_T **list_stack)
{
    int		todo;
    int		abort = FALSE;
    hashitem_T	*hi;
    hashtab_T	*cur_ht;
    ht_stack_T	*ht_stack = NULL;
    ht_stack_T	*tempitem;

    cur_ht = ht;
    for (;;)
    {
	if (!abort)
	{
	    /* Mark each item in the hashtab.  If the item contains a hashtab
	     * it is added to ht_stack, if it contains a list it is added to
	     * list_stack. */
	    todo = (int)cur_ht->ht_used;
	    for (hi = cur_ht->ht_array; todo > 0; ++hi)
		if (!HASHITEM_EMPTY(hi))
		{
		    --todo;
		    abort = abort || set_ref_in_item(&HI2DI(hi)->di_tv, copyID,
						       &ht_stack, list_stack);
		}
	}

	if (ht_stack == NULL)
	    break;

	/* take an item from the stack */
	cur_ht = ht_stack->ht;
	tempitem = ht_stack;
	ht_stack = ht_stack->prev;
	free(tempitem);
    }

    return abort;
}

/*
 * Mark all lists and dicts referenced through list "l" with "copyID".
 * "ht_stack" is used to add hashtabs to be marked.  Can be NULL.
 *
 * Returns TRUE if setting references failed somehow.
 */
    int
set_ref_in_list(list_T *l, int copyID, ht_stack_T **ht_stack)
{
    listitem_T	 *li;
    int		 abort = FALSE;
    list_T	 *cur_l;
    list_stack_T *list_stack = NULL;
    list_stack_T *tempitem;

    cur_l = l;
    for (;;)
    {
	if (!abort)
	    /* Mark each item in the list.  If the item contains a hashtab
	     * it is added to ht_stack, if it contains a list it is added to
	     * list_stack. */
	    for (li = cur_l->lv_first; !abort && li != NULL; li = li->li_next)
		abort = abort || set_ref_in_item(&li->li_tv, copyID,
						       ht_stack, &list_stack);
	if (list_stack == NULL)
	    break;

	/* take an item from the stack */
	cur_l = list_stack->list;
	tempitem = list_stack;
	list_stack = list_stack->prev;
	free(tempitem);
    }

    return abort;
}

/*
 * Mark all lists and dicts referenced through typval "tv" with "copyID".
 * "list_stack" is used to add lists to be marked.  Can be NULL.
 * "ht_stack" is used to add hashtabs to be marked.  Can be NULL.
 *
 * Returns TRUE if setting references failed somehow.
 */
    int
set_ref_in_item(
    typval_T	    *tv,
    int		    copyID,
    ht_stack_T	    **ht_stack,
    list_stack_T    **list_stack)
{
    int		abort = FALSE;

    if (tv->v_type == VAR_DICT)
    {
	dict_T	*dd = tv->vval.v_dict;

	if (dd != NULL && dd->dv_copyID != copyID)
	{
	    /* Didn't see this dict yet. */
	    dd->dv_copyID = copyID;
	    if (ht_stack == NULL)
	    {
		abort = set_ref_in_ht(&dd->dv_hashtab, copyID, list_stack);
	    }
	    else
	    {
		ht_stack_T *newitem = (ht_stack_T*)malloc(sizeof(ht_stack_T));
		if (newitem == NULL)
		    abort = TRUE;
		else
		{
		    newitem->ht = &dd->dv_hashtab;
		    newitem->prev = *ht_stack;
		    *ht_stack = newitem;
		}
	    }
	}
    }
    else if (tv->v_type == VAR_LIST)
    {
	list_T	*ll = tv->vval.v_list;

	if (ll != NULL && ll->lv_copyID != copyID)
	{
	    /* Didn't see this list yet. */
	    ll->lv_copyID = copyID;
	    if (list_stack == NULL)
	    {
		abort = set_ref_in_list(ll, copyID, ht_stack);
	    }
	    else
	    {
		list_stack_T *newitem = (list_stack_T*)malloc(
							sizeof(list_stack_T));
		if (newitem == NULL)
		    abort = TRUE;
		else
		{
		    newitem->list = ll;
		    newitem->prev = *list_stack;
		    *list_stack = newitem;
		}
	    }
	}
    }
    else if (tv->v_type == VAR_FUNC)
    {
	abort = set_ref_in_func(tv->vval.v_string, NULL, copyID);
    }
    else if (tv->v_type == VAR_PARTIAL)
    {
	partial_T	*pt = tv->vval.v_partial;
	int		i;

	/* A partial does not have a copyID, because it cannot contain itself.
	 */
	if (pt != NULL)
	{
	    abort = set_ref_in_func(pt->pt_name, pt->pt_func, copyID);

	    if (pt->pt_dict != NULL)
	    {
		typval_T dtv;

		dtv.v_type = VAR_DICT;
		dtv.vval.v_dict = pt->pt_dict;
		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
	    }

	    for (i = 0; i < pt->pt_argc; ++i)
		abort = abort || set_ref_in_item(&pt->pt_argv[i], copyID,
							ht_stack, list_stack);
	}
    }
#ifdef FEAT_JOB_CHANNEL
    else if (tv->v_type == VAR_JOB)
    {
	job_T	    *job = tv->vval.v_job;
	typval_T    dtv;

	if (job != NULL && job->jv_copyID != copyID)
	{
	    job->jv_copyID = copyID;
	    if (job->jv_channel != NULL)
	    {
		dtv.v_type = VAR_CHANNEL;
		dtv.vval.v_channel = job->jv_channel;
		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
	    }
	    if (job->jv_exit_partial != NULL)
	    {
		dtv.v_type = VAR_PARTIAL;
		dtv.vval.v_partial = job->jv_exit_partial;
		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
	    }
	}
    }
    else if (tv->v_type == VAR_CHANNEL)
    {
	channel_T   *ch =tv->vval.v_channel;
	ch_part_T   part;
	typval_T    dtv;
	jsonq_T	    *jq;
	cbq_T	    *cq;

	if (ch != NULL && ch->ch_copyID != copyID)
	{
	    ch->ch_copyID = copyID;
	    for (part = PART_SOCK; part < PART_COUNT; ++part)
	    {
		for (jq = ch->ch_part[part].ch_json_head.jq_next; jq != NULL;
							     jq = jq->jq_next)
		    set_ref_in_item(jq->jq_value, copyID, ht_stack, list_stack);
		for (cq = ch->ch_part[part].ch_cb_head.cq_next; cq != NULL;
							     cq = cq->cq_next)
		    if (cq->cq_partial != NULL)
		    {
			dtv.v_type = VAR_PARTIAL;
			dtv.vval.v_partial = cq->cq_partial;
			set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
		    }
		if (ch->ch_part[part].ch_partial != NULL)
		{
		    dtv.v_type = VAR_PARTIAL;
		    dtv.vval.v_partial = ch->ch_part[part].ch_partial;
		    set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
		}
	    }
	    if (ch->ch_partial != NULL)
	    {
		dtv.v_type = VAR_PARTIAL;
		dtv.vval.v_partial = ch->ch_partial;
		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
	    }
	    if (ch->ch_close_partial != NULL)
	    {
		dtv.v_type = VAR_PARTIAL;
		dtv.vval.v_partial = ch->ch_close_partial;
		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
	    }
	}
    }
#endif
    return abort;
}

    static char *
get_var_special_name(int nr)
{
    switch (nr)
    {
	case VVAL_FALSE: return "v:false";
	case VVAL_TRUE:  return "v:true";
	case VVAL_NONE:  return "v:none";
	case VVAL_NULL:  return "v:null";
    }
    internal_error("get_var_special_name()");
    return "42";
}

/*
 * Return a string with the string representation of a variable.
 * If the memory is allocated "tofree" is set to it, otherwise NULL.
 * "numbuf" is used for a number.
 * When "copyID" is not NULL replace recursive lists and dicts with "...".
 * When both "echo_style" and "composite_val" are FALSE, put quotes around
 * stings as "string()", otherwise does not put quotes around strings, as
 * ":echo" displays values.
 * When "restore_copyID" is FALSE, repeated items in dictionaries and lists
 * are replaced with "...".
 * May return NULL.
 */
    char_u *
echo_string_core(
    typval_T	*tv,
    char_u	**tofree,
    char_u	*numbuf,
    int		copyID,
    int		echo_style,
    int		restore_copyID,
    int		composite_val)
{
    static int	recurse = 0;
    char_u	*r = NULL;

    if (recurse >= DICT_MAXNEST)
    {
	if (!did_echo_string_emsg)
	{
	    /* Only give this message once for a recursive call to avoid
	     * flooding the user with errors.  And stop iterating over lists
	     * and dicts. */
	    did_echo_string_emsg = TRUE;
	    EMSG(_("E724: variable nested too deep for displaying"));
	}
	*tofree = NULL;
	return (char_u *)"{E724}";
    }
    ++recurse;

    switch (tv->v_type)
    {
	case VAR_STRING:
	    if (echo_style && !composite_val)
	    {
		*tofree = NULL;
		r = tv->vval.v_string;
		if (r == NULL)
		    r = (char_u *)"";
	    }
	    else
	    {
		*tofree = string_quote(tv->vval.v_string, FALSE);
		r = *tofree;
	    }
	    break;

	case VAR_FUNC:
	    if (echo_style)
	    {
		*tofree = NULL;
		r = tv->vval.v_string;
	    }
	    else
	    {
		*tofree = string_quote(tv->vval.v_string, TRUE);
		r = *tofree;
	    }
	    break;

	case VAR_PARTIAL:
	    {
		partial_T   *pt = tv->vval.v_partial;
		char_u	    *fname = string_quote(pt == NULL ? NULL
						    : partial_name(pt), FALSE);
		garray_T    ga;
		int	    i;
		char_u	    *tf;

		ga_init2(&ga, 1, 100);
		ga_concat(&ga, (char_u *)"function(");
		if (fname != NULL)
		{
		    ga_concat(&ga, fname);
		    vim_free(fname);
		}
		if (pt != NULL && pt->pt_argc > 0)
		{
		    ga_concat(&ga, (char_u *)", [");
		    for (i = 0; i < pt->pt_argc; ++i)
		    {
			if (i > 0)
			    ga_concat(&ga, (char_u *)", ");
			ga_concat(&ga,
			     tv2string(&pt->pt_argv[i], &tf, numbuf, copyID));
			vim_free(tf);
		    }
		    ga_concat(&ga, (char_u *)"]");
		}
		if (pt != NULL && pt->pt_dict != NULL)
		{
		    typval_T dtv;

		    ga_concat(&ga, (char_u *)", ");
		    dtv.v_type = VAR_DICT;
		    dtv.vval.v_dict = pt->pt_dict;
		    ga_concat(&ga, tv2string(&dtv, &tf, numbuf, copyID));
		    vim_free(tf);
		}
		ga_concat(&ga, (char_u *)")");

		*tofree = ga.ga_data;
		r = *tofree;
		break;
	    }

	case VAR_LIST:
	    if (tv->vval.v_list == NULL)
	    {
		*tofree = NULL;
		r = NULL;
	    }
	    else if (copyID != 0 && tv->vval.v_list->lv_copyID == copyID
		    && tv->vval.v_list->lv_len > 0)
	    {
		*tofree = NULL;
		r = (char_u *)"[...]";
	    }
	    else
	    {
		int old_copyID = tv->vval.v_list->lv_copyID;

		tv->vval.v_list->lv_copyID = copyID;
		*tofree = list2string(tv, copyID, restore_copyID);
		if (restore_copyID)
		    tv->vval.v_list->lv_copyID = old_copyID;
		r = *tofree;
	    }
	    break;

	case VAR_DICT:
	    if (tv->vval.v_dict == NULL)
	    {
		*tofree = NULL;
		r = NULL;
	    }
	    else if (copyID != 0 && tv->vval.v_dict->dv_copyID == copyID
		    && tv->vval.v_dict->dv_hashtab.ht_used != 0)
	    {
		*tofree = NULL;
		r = (char_u *)"{...}";
	    }
	    else
	    {
		int old_copyID = tv->vval.v_dict->dv_copyID;
		tv->vval.v_dict->dv_copyID = copyID;
		*tofree = dict2string(tv, copyID, restore_copyID);
		if (restore_copyID)
		    tv->vval.v_dict->dv_copyID = old_copyID;
		r = *tofree;
	    }
	    break;

	case VAR_NUMBER:
	case VAR_UNKNOWN:
	    *tofree = NULL;
	    r = get_tv_string_buf(tv, numbuf);
	    break;

	case VAR_JOB:
	case VAR_CHANNEL:
	    *tofree = NULL;
	    r = get_tv_string_buf(tv, numbuf);
	    if (composite_val)
	    {
		*tofree = string_quote(r, FALSE);
		r = *tofree;
	    }
	    break;

	case VAR_FLOAT:
#ifdef FEAT_FLOAT
	    *tofree = NULL;
	    vim_snprintf((char *)numbuf, NUMBUFLEN, "%g", tv->vval.v_float);
	    r = numbuf;
	    break;
#endif

	case VAR_SPECIAL:
	    *tofree = NULL;
	    r = (char_u *)get_var_special_name(tv->vval.v_number);
	    break;
    }

    if (--recurse == 0)
	did_echo_string_emsg = FALSE;
    return r;
}

/*
 * Return a string with the string representation of a variable.
 * If the memory is allocated "tofree" is set to it, otherwise NULL.
 * "numbuf" is used for a number.
 * Does not put quotes around strings, as ":echo" displays values.
 * When "copyID" is not NULL replace recursive lists and dicts with "...".
 * May return NULL.
 */
    char_u *
echo_string(
    typval_T	*tv,
    char_u	**tofree,
    char_u	*numbuf,
    int		copyID)
{
    return echo_string_core(tv, tofree, numbuf, copyID, TRUE, FALSE, FALSE);
}

/*
 * Return a string with the string representation of a variable.
 * If the memory is allocated "tofree" is set to it, otherwise NULL.
 * "numbuf" is used for a number.
 * Puts quotes around strings, so that they can be parsed back by eval().
 * May return NULL.
 */
    char_u *
tv2string(
    typval_T	*tv,
    char_u	**tofree,
    char_u	*numbuf,
    int		copyID)
{
    return echo_string_core(tv, tofree, numbuf, copyID, FALSE, TRUE, FALSE);
}

/*
 * Return string "str" in ' quotes, doubling ' characters.
 * If "str" is NULL an empty string is assumed.
 * If "function" is TRUE make it function('string').
 */
    char_u *
string_quote(char_u *str, int function)
{
    unsigned	len;
    char_u	*p, *r, *s;

    len = (function ? 13 : 3);
    if (str != NULL)
    {
	len += (unsigned)STRLEN(str);
	for (p = str; *p != NUL; MB_PTR_ADV(p))
	    if (*p == '\'')
		++len;
    }
    s = r = alloc(len);
    if (r != NULL)
    {
	if (function)
	{
	    STRCPY(r, "function('");
	    r += 10;
	}
	else
	    *r++ = '\'';
	if (str != NULL)
	    for (p = str; *p != NUL; )
	    {
		if (*p == '\'')
		    *r++ = '\'';
		MB_COPY_CHAR(p, r);
	    }
	*r++ = '\'';
	if (function)
	    *r++ = ')';
	*r++ = NUL;
    }
    return s;
}

#if defined(FEAT_FLOAT) || defined(PROTO)
/*
 * Convert the string "text" to a floating point number.
 * This uses strtod().  setlocale(LC_NUMERIC, "C") has been used to make sure
 * this always uses a decimal point.
 * Returns the length of the text that was consumed.
 */
    int
string2float(
    char_u	*text,
    float_T	*value)	    /* result stored here */
{
    char	*s = (char *)text;
    float_T	f;

    /* MS-Windows does not deal with "inf" and "nan" properly. */
    if (STRNICMP(text, "inf", 3) == 0)
    {
	*value = INFINITY;
	return 3;
    }
    if (STRNICMP(text, "-inf", 3) == 0)
    {
	*value = -INFINITY;
	return 4;
    }
    if (STRNICMP(text, "nan", 3) == 0)
    {
	*value = NAN;
	return 3;
    }
    f = strtod(s, &s);
    *value = f;
    return (int)((char_u *)s - text);
}
#endif

/*
 * Get the value of an environment variable.
 * "arg" is pointing to the '$'.  It is advanced to after the name.
 * If the environment variable was not set, silently assume it is empty.
 * Return FAIL if the name is invalid.
 */
    static int
get_env_tv(char_u **arg, typval_T *rettv, int evaluate)
{
    char_u	*string = NULL;
    int		len;
    int		cc;
    char_u	*name;
    int		mustfree = FALSE;

    ++*arg;
    name = *arg;
    len = get_env_len(arg);
    if (evaluate)
    {
	if (len == 0)
	    return FAIL; /* invalid empty name */

	cc = name[len];
	name[len] = NUL;
	/* first try vim_getenv(), fast for normal environment vars */
	string = vim_getenv(name, &mustfree);
	if (string != NULL && *string != NUL)
	{
	    if (!mustfree)
		string = vim_strsave(string);
	}
	else
	{
	    if (mustfree)
		vim_free(string);

	    /* next try expanding things like $VIM and ${HOME} */
	    string = expand_env_save(name - 1);
	    if (string != NULL && *string == '$')
	    {
		vim_free(string);
		string = NULL;
	    }
	}
	name[len] = cc;

	rettv->v_type = VAR_STRING;
	rettv->vval.v_string = string;
    }

    return OK;
}



/*
 * Translate a String variable into a position.
 * Returns NULL when there is an error.
 */
    pos_T *
var2fpos(
    typval_T	*varp,
    int		dollar_lnum,	/* TRUE when $ is last line */
    int		*fnum)		/* set to fnum for '0, 'A, etc. */
{
    char_u		*name;
    static pos_T	pos;
    pos_T		*pp;

    /* Argument can be [lnum, col, coladd]. */
    if (varp->v_type == VAR_LIST)
    {
	list_T		*l;
	int		len;
	int		error = FALSE;
	listitem_T	*li;

	l = varp->vval.v_list;
	if (l == NULL)
	    return NULL;

	/* Get the line number */
	pos.lnum = list_find_nr(l, 0L, &error);
	if (error || pos.lnum <= 0 || pos.lnum > curbuf->b_ml.ml_line_count)
	    return NULL;	/* invalid line number */

	/* Get the column number */
	pos.col = list_find_nr(l, 1L, &error);
	if (error)
	    return NULL;
	len = (long)STRLEN(ml_get(pos.lnum));

	/* We accept "$" for the column number: last column. */
	li = list_find(l, 1L);
	if (li != NULL && li->li_tv.v_type == VAR_STRING
		&& li->li_tv.vval.v_string != NULL
		&& STRCMP(li->li_tv.vval.v_string, "$") == 0)
	    pos.col = len + 1;

	/* Accept a position up to the NUL after the line. */
	if (pos.col == 0 || (int)pos.col > len + 1)
	    return NULL;	/* invalid column number */
	--pos.col;

#ifdef FEAT_VIRTUALEDIT
	/* Get the virtual offset.  Defaults to zero. */
	pos.coladd = list_find_nr(l, 2L, &error);
	if (error)
	    pos.coladd = 0;
#endif

	return &pos;
    }

    name = get_tv_string_chk(varp);
    if (name == NULL)
	return NULL;
    if (name[0] == '.')				/* cursor */
	return &curwin->w_cursor;
    if (name[0] == 'v' && name[1] == NUL)	/* Visual start */
    {
	if (VIsual_active)
	    return &VIsual;
	return &curwin->w_cursor;
    }
    if (name[0] == '\'')			/* mark */
    {
	pp = getmark_buf_fnum(curbuf, name[1], FALSE, fnum);
	if (pp == NULL || pp == (pos_T *)-1 || pp->lnum <= 0)
	    return NULL;
	return pp;
    }

#ifdef FEAT_VIRTUALEDIT
    pos.coladd = 0;
#endif

    if (name[0] == 'w' && dollar_lnum)
    {
	pos.col = 0;
	if (name[1] == '0')		/* "w0": first visible line */
	{
	    update_topline();
	    /* In silent Ex mode topline is zero, but that's not a valid line
	     * number; use one instead. */
	    pos.lnum = curwin->w_topline > 0 ? curwin->w_topline : 1;
	    return &pos;
	}
	else if (name[1] == '$')	/* "w$": last visible line */
	{
	    validate_botline();
	    /* In silent Ex mode botline is zero, return zero then. */
	    pos.lnum = curwin->w_botline > 0 ? curwin->w_botline - 1 : 0;
	    return &pos;
	}
    }
    else if (name[0] == '$')		/* last column or line */
    {
	if (dollar_lnum)
	{
	    pos.lnum = curbuf->b_ml.ml_line_count;
	    pos.col = 0;
	}
	else
	{
	    pos.lnum = curwin->w_cursor.lnum;
	    pos.col = (colnr_T)STRLEN(ml_get_curline());
	}
	return &pos;
    }
    return NULL;
}

/*
 * Convert list in "arg" into a position and optional file number.
 * When "fnump" is NULL there is no file number, only 3 items.
 * Note that the column is passed on as-is, the caller may want to decrement
 * it to use 1 for the first column.
 * Return FAIL when conversion is not possible, doesn't check the position for
 * validity.
 */
    int
list2fpos(
    typval_T	*arg,
    pos_T	*posp,
    int		*fnump,
    colnr_T	*curswantp)
{
    list_T	*l = arg->vval.v_list;
    long	i = 0;
    long	n;

    /* List must be: [fnum, lnum, col, coladd, curswant], where "fnum" is only
     * there when "fnump" isn't NULL; "coladd" and "curswant" are optional. */
    if (arg->v_type != VAR_LIST
	    || l == NULL
	    || l->lv_len < (fnump == NULL ? 2 : 3)
	    || l->lv_len > (fnump == NULL ? 4 : 5))
	return FAIL;

    if (fnump != NULL)
    {
	n = list_find_nr(l, i++, NULL);	/* fnum */
	if (n < 0)
	    return FAIL;
	if (n == 0)
	    n = curbuf->b_fnum;		/* current buffer */
	*fnump = n;
    }

    n = list_find_nr(l, i++, NULL);	/* lnum */
    if (n < 0)
	return FAIL;
    posp->lnum = n;

    n = list_find_nr(l, i++, NULL);	/* col */
    if (n < 0)
	return FAIL;
    posp->col = n;

#ifdef FEAT_VIRTUALEDIT
    n = list_find_nr(l, i, NULL);	/* off */
    if (n < 0)
	posp->coladd = 0;
    else
	posp->coladd = n;
#endif

    if (curswantp != NULL)
	*curswantp = list_find_nr(l, i + 1, NULL);  /* curswant */

    return OK;
}

/*
 * Get the length of an environment variable name.
 * Advance "arg" to the first character after the name.
 * Return 0 for error.
 */
    static int
get_env_len(char_u **arg)
{
    char_u	*p;
    int		len;

    for (p = *arg; vim_isIDc(*p); ++p)
	;
    if (p == *arg)	    /* no name found */
	return 0;

    len = (int)(p - *arg);
    *arg = p;
    return len;
}

/*
 * Get the length of the name of a function or internal variable.
 * "arg" is advanced to the first non-white character after the name.
 * Return 0 if something is wrong.
 */
    int
get_id_len(char_u **arg)
{
    char_u	*p;
    int		len;

    /* Find the end of the name. */
    for (p = *arg; eval_isnamec(*p); ++p)
    {
	if (*p == ':')
	{
	    /* "s:" is start of "s:var", but "n:" is not and can be used in
	     * slice "[n:]".  Also "xx:" is not a namespace. */
	    len = (int)(p - *arg);
	    if ((len == 1 && vim_strchr(NAMESPACE_CHAR, **arg) == NULL)
		    || len > 1)
		break;
	}
    }
    if (p == *arg)	    /* no name found */
	return 0;

    len = (int)(p - *arg);
    *arg = skipwhite(p);

    return len;
}

/*
 * Get the length of the name of a variable or function.
 * Only the name is recognized, does not handle ".key" or "[idx]".
 * "arg" is advanced to the first non-white character after the name.
 * Return -1 if curly braces expansion failed.
 * Return 0 if something else is wrong.
 * If the name contains 'magic' {}'s, expand them and return the
 * expanded name in an allocated string via 'alias' - caller must free.
 */
    int
get_name_len(
    char_u	**arg,
    char_u	**alias,
    int		evaluate,
    int		verbose)
{
    int		len;
    char_u	*p;
    char_u	*expr_start;
    char_u	*expr_end;

    *alias = NULL;  /* default to no alias */

    if ((*arg)[0] == K_SPECIAL && (*arg)[1] == KS_EXTRA
						  && (*arg)[2] == (int)KE_SNR)
    {
	/* hard coded <SNR>, already translated */
	*arg += 3;
	return get_id_len(arg) + 3;
    }
    len = eval_fname_script(*arg);
    if (len > 0)
    {
	/* literal "<SID>", "s:" or "<SNR>" */
	*arg += len;
    }

    /*
     * Find the end of the name; check for {} construction.
     */
    p = find_name_end(*arg, &expr_start, &expr_end,
					       len > 0 ? 0 : FNE_CHECK_START);
    if (expr_start != NULL)
    {
	char_u	*temp_string;

	if (!evaluate)
	{
	    len += (int)(p - *arg);
	    *arg = skipwhite(p);
	    return len;
	}

	/*
	 * Include any <SID> etc in the expanded string:
	 * Thus the -len here.
	 */
	temp_string = make_expanded_name(*arg - len, expr_start, expr_end, p);
	if (temp_string == NULL)
	    return -1;
	*alias = temp_string;
	*arg = skipwhite(p);
	return (int)STRLEN(temp_string);
    }

    len += get_id_len(arg);
    if (len == 0 && verbose)
	EMSG2(_(e_invexpr2), *arg);

    return len;
}

/*
 * Find the end of a variable or function name, taking care of magic braces.
 * If "expr_start" is not NULL then "expr_start" and "expr_end" are set to the
 * start and end of the first magic braces item.
 * "flags" can have FNE_INCL_BR and FNE_CHECK_START.
 * Return a pointer to just after the name.  Equal to "arg" if there is no
 * valid name.
 */
    char_u *
find_name_end(
    char_u	*arg,
    char_u	**expr_start,
    char_u	**expr_end,
    int		flags)
{
    int		mb_nest = 0;
    int		br_nest = 0;
    char_u	*p;
    int		len;

    if (expr_start != NULL)
    {
	*expr_start = NULL;
	*expr_end = NULL;
    }

    /* Quick check for valid starting character. */
    if ((flags & FNE_CHECK_START) && !eval_isnamec1(*arg) && *arg != '{')
	return arg;

    for (p = arg; *p != NUL
		    && (eval_isnamec(*p)
			|| *p == '{'
			|| ((flags & FNE_INCL_BR) && (*p == '[' || *p == '.'))
			|| mb_nest != 0
			|| br_nest != 0); MB_PTR_ADV(p))
    {
	if (*p == '\'')
	{
	    /* skip over 'string' to avoid counting [ and ] inside it. */
	    for (p = p + 1; *p != NUL && *p != '\''; MB_PTR_ADV(p))
		;
	    if (*p == NUL)
		break;
	}
	else if (*p == '"')
	{
	    /* skip over "str\"ing" to avoid counting [ and ] inside it. */
	    for (p = p + 1; *p != NUL && *p != '"'; MB_PTR_ADV(p))
		if (*p == '\\' && p[1] != NUL)
		    ++p;
	    if (*p == NUL)
		break;
	}
	else if (br_nest == 0 && mb_nest == 0 && *p == ':')
	{
	    /* "s:" is start of "s:var", but "n:" is not and can be used in
	     * slice "[n:]".  Also "xx:" is not a namespace. But {ns}: is. */
	    len = (int)(p - arg);
	    if ((len == 1 && vim_strchr(NAMESPACE_CHAR, *arg) == NULL)
		    || (len > 1 && p[-1] != '}'))
		break;
	}

	if (mb_nest == 0)
	{
	    if (*p == '[')
		++br_nest;
	    else if (*p == ']')
		--br_nest;
	}

	if (br_nest == 0)
	{
	    if (*p == '{')
	    {
		mb_nest++;
		if (expr_start != NULL && *expr_start == NULL)
		    *expr_start = p;
	    }
	    else if (*p == '}')
	    {
		mb_nest--;
		if (expr_start != NULL && mb_nest == 0 && *expr_end == NULL)
		    *expr_end = p;
	    }
	}
    }

    return p;
}

/*
 * Expands out the 'magic' {}'s in a variable/function name.
 * Note that this can call itself recursively, to deal with
 * constructs like foo{bar}{baz}{bam}
 * The four pointer arguments point to "foo{expre}ss{ion}bar"
 *			"in_start"      ^
 *			"expr_start"	   ^
 *			"expr_end"		 ^
 *			"in_end"			    ^
 *
 * Returns a new allocated string, which the caller must free.
 * Returns NULL for failure.
 */
    static char_u *
make_expanded_name(
    char_u	*in_start,
    char_u	*expr_start,
    char_u	*expr_end,
    char_u	*in_end)
{
    char_u	c1;
    char_u	*retval = NULL;
    char_u	*temp_result;
    char_u	*nextcmd = NULL;

    if (expr_end == NULL || in_end == NULL)
	return NULL;
    *expr_start	= NUL;
    *expr_end = NUL;
    c1 = *in_end;
    *in_end = NUL;

    temp_result = eval_to_string(expr_start + 1, &nextcmd, FALSE);
    if (temp_result != NULL && nextcmd == NULL)
    {
	retval = alloc((unsigned)(STRLEN(temp_result) + (expr_start - in_start)
						   + (in_end - expr_end) + 1));
	if (retval != NULL)
	{
	    STRCPY(retval, in_start);
	    STRCAT(retval, temp_result);
	    STRCAT(retval, expr_end + 1);
	}
    }
    vim_free(temp_result);

    *in_end = c1;		/* put char back for error messages */
    *expr_start = '{';
    *expr_end = '}';

    if (retval != NULL)
    {
	temp_result = find_name_end(retval, &expr_start, &expr_end, 0);
	if (expr_start != NULL)
	{
	    /* Further expansion! */
	    temp_result = make_expanded_name(retval, expr_start,
						       expr_end, temp_result);
	    vim_free(retval);
	    retval = temp_result;
	}
    }

    return retval;
}

/*
 * Return TRUE if character "c" can be used in a variable or function name.
 * Does not include '{' or '}' for magic braces.
 */
    int
eval_isnamec(int c)
{
    return (ASCII_ISALNUM(c) || c == '_' || c == ':' || c == AUTOLOAD_CHAR);
}

/*
 * Return TRUE if character "c" can be used as the first character in a
 * variable or function name (excluding '{' and '}').
 */
    int
eval_isnamec1(int c)
{
    return (ASCII_ISALPHA(c) || c == '_');
}

/*
 * Set number v: variable to "val".
 */
    void
set_vim_var_nr(int idx, varnumber_T val)
{
    vimvars[idx].vv_nr = val;
}

/*
 * Get number v: variable value.
 */
    varnumber_T
get_vim_var_nr(int idx)
{
    return vimvars[idx].vv_nr;
}

/*
 * Get string v: variable value.  Uses a static buffer, can only be used once.
 */
    char_u *
get_vim_var_str(int idx)
{
    return get_tv_string(&vimvars[idx].vv_tv);
}

/*
 * Get List v: variable value.  Caller must take care of reference count when
 * needed.
 */
    list_T *
get_vim_var_list(int idx)
{
    return vimvars[idx].vv_list;
}

/*
 * Set v:char to character "c".
 */
    void
set_vim_var_char(int c)
{
    char_u	buf[MB_MAXBYTES + 1];

#ifdef FEAT_MBYTE
    if (has_mbyte)
	buf[(*mb_char2bytes)(c, buf)] = NUL;
    else
#endif
    {
	buf[0] = c;
	buf[1] = NUL;
    }
    set_vim_var_string(VV_CHAR, buf, -1);
}

/*
 * Set v:count to "count" and v:count1 to "count1".
 * When "set_prevcount" is TRUE first set v:prevcount from v:count.
 */
    void
set_vcount(
    long	count,
    long	count1,
    int		set_prevcount)
{
    if (set_prevcount)
	vimvars[VV_PREVCOUNT].vv_nr = vimvars[VV_COUNT].vv_nr;
    vimvars[VV_COUNT].vv_nr = count;
    vimvars[VV_COUNT1].vv_nr = count1;
}

/*
 * Set string v: variable to a copy of "val".
 */
    void
set_vim_var_string(
    int		idx,
    char_u	*val,
    int		len)	    /* length of "val" to use or -1 (whole string) */
{
    clear_tv(&vimvars[idx].vv_di.di_tv);
    vimvars[idx].vv_type = VAR_STRING;
    if (val == NULL)
	vimvars[idx].vv_str = NULL;
    else if (len == -1)
	vimvars[idx].vv_str = vim_strsave(val);
    else
	vimvars[idx].vv_str = vim_strnsave(val, len);
}

/*
 * Set List v: variable to "val".
 */
    void
set_vim_var_list(int idx, list_T *val)
{
    clear_tv(&vimvars[idx].vv_di.di_tv);
    vimvars[idx].vv_type = VAR_LIST;
    vimvars[idx].vv_list = val;
    if (val != NULL)
	++val->lv_refcount;
}

/*
 * Set Dictionary v: variable to "val".
 */
    void
set_vim_var_dict(int idx, dict_T *val)
{
    int		todo;
    hashitem_T	*hi;

    clear_tv(&vimvars[idx].vv_di.di_tv);
    vimvars[idx].vv_type = VAR_DICT;
    vimvars[idx].vv_dict = val;
    if (val != NULL)
    {
	++val->dv_refcount;

	/* Set readonly */
	todo = (int)val->dv_hashtab.ht_used;
	for (hi = val->dv_hashtab.ht_array; todo > 0 ; ++hi)
	{
	    if (HASHITEM_EMPTY(hi))
		continue;
	    --todo;
	    HI2DI(hi)->di_flags |= DI_FLAGS_RO | DI_FLAGS_FIX;
	}
    }
}

/*
 * Set v:register if needed.
 */
    void
set_reg_var(int c)
{
    char_u	regname;

    if (c == 0 || c == ' ')
	regname = '"';
    else
	regname = c;
    /* Avoid free/alloc when the value is already right. */
    if (vimvars[VV_REG].vv_str == NULL || vimvars[VV_REG].vv_str[0] != c)
	set_vim_var_string(VV_REG, &regname, 1);
}

/*
 * Get or set v:exception.  If "oldval" == NULL, return the current value.
 * Otherwise, restore the value to "oldval" and return NULL.
 * Must always be called in pairs to save and restore v:exception!  Does not
 * take care of memory allocations.
 */
    char_u *
v_exception(char_u *oldval)
{
    if (oldval == NULL)
	return vimvars[VV_EXCEPTION].vv_str;

    vimvars[VV_EXCEPTION].vv_str = oldval;
    return NULL;
}

/*
 * Get or set v:throwpoint.  If "oldval" == NULL, return the current value.
 * Otherwise, restore the value to "oldval" and return NULL.
 * Must always be called in pairs to save and restore v:throwpoint!  Does not
 * take care of memory allocations.
 */
    char_u *
v_throwpoint(char_u *oldval)
{
    if (oldval == NULL)
	return vimvars[VV_THROWPOINT].vv_str;

    vimvars[VV_THROWPOINT].vv_str = oldval;
    return NULL;
}

#if defined(FEAT_AUTOCMD) || defined(PROTO)
/*
 * Set v:cmdarg.
 * If "eap" != NULL, use "eap" to generate the value and return the old value.
 * If "oldarg" != NULL, restore the value to "oldarg" and return NULL.
 * Must always be called in pairs!
 */
    char_u *
set_cmdarg(exarg_T *eap, char_u *oldarg)
{
    char_u	*oldval;
    char_u	*newval;
    unsigned	len;

    oldval = vimvars[VV_CMDARG].vv_str;
    if (eap == NULL)
    {
	vim_free(oldval);
	vimvars[VV_CMDARG].vv_str = oldarg;
	return NULL;
    }

    if (eap->force_bin == FORCE_BIN)
	len = 6;
    else if (eap->force_bin == FORCE_NOBIN)
	len = 8;
    else
	len = 0;

    if (eap->read_edit)
	len += 7;

    if (eap->force_ff != 0)
	len += (unsigned)STRLEN(eap->cmd + eap->force_ff) + 6;
# ifdef FEAT_MBYTE
    if (eap->force_enc != 0)
	len += (unsigned)STRLEN(eap->cmd + eap->force_enc) + 7;
    if (eap->bad_char != 0)
	len += 7 + 4;  /* " ++bad=" + "keep" or "drop" */
# endif

    newval = alloc(len + 1);
    if (newval == NULL)
	return NULL;

    if (eap->force_bin == FORCE_BIN)
	sprintf((char *)newval, " ++bin");
    else if (eap->force_bin == FORCE_NOBIN)
	sprintf((char *)newval, " ++nobin");
    else
	*newval = NUL;

    if (eap->read_edit)
	STRCAT(newval, " ++edit");

    if (eap->force_ff != 0)
	sprintf((char *)newval + STRLEN(newval), " ++ff=%s",
						eap->cmd + eap->force_ff);
# ifdef FEAT_MBYTE
    if (eap->force_enc != 0)
	sprintf((char *)newval + STRLEN(newval), " ++enc=%s",
					       eap->cmd + eap->force_enc);
    if (eap->bad_char == BAD_KEEP)
	STRCPY(newval + STRLEN(newval), " ++bad=keep");
    else if (eap->bad_char == BAD_DROP)
	STRCPY(newval + STRLEN(newval), " ++bad=drop");
    else if (eap->bad_char != 0)
	sprintf((char *)newval + STRLEN(newval), " ++bad=%c", eap->bad_char);
# endif
    vimvars[VV_CMDARG].vv_str = newval;
    return oldval;
}
#endif

/*
 * Get the value of internal variable "name".
 * Return OK or FAIL.
 */
    int
get_var_tv(
    char_u	*name,
    int		len,		/* length of "name" */
    typval_T	*rettv,		/* NULL when only checking existence */
    dictitem_T	**dip,		/* non-NULL when typval's dict item is needed */
    int		verbose,	/* may give error message */
    int		no_autoload)	/* do not use script autoloading */
{
    int		ret = OK;
    typval_T	*tv = NULL;
    dictitem_T	*v;
    int		cc;

    /* truncate the name, so that we can use strcmp() */
    cc = name[len];
    name[len] = NUL;

    /*
     * Check for user-defined variables.
     */
    v = find_var(name, NULL, no_autoload);
    if (v != NULL)
    {
	tv = &v->di_tv;
	if (dip != NULL)
	    *dip = v;
    }

    if (tv == NULL)
    {
	if (rettv != NULL && verbose)
	    EMSG2(_(e_undefvar), name);
	ret = FAIL;
    }
    else if (rettv != NULL)
	copy_tv(tv, rettv);

    name[len] = cc;

    return ret;
}

/*
 * Check if variable "name[len]" is a local variable or an argument.
 * If so, "*eval_lavars_used" is set to TRUE.
 */
    static void
check_vars(char_u *name, int len)
{
    int		cc;
    char_u	*varname;
    hashtab_T	*ht;

    if (eval_lavars_used == NULL)
	return;

    /* truncate the name, so that we can use strcmp() */
    cc = name[len];
    name[len] = NUL;

    ht = find_var_ht(name, &varname);
    if (ht == get_funccal_local_ht() || ht == get_funccal_args_ht())
    {
	if (find_var(name, NULL, TRUE) != NULL)
	    *eval_lavars_used = TRUE;
    }

    name[len] = cc;
}

/*
 * Handle expr[expr], expr[expr:expr] subscript and .name lookup.
 * Also handle function call with Funcref variable: func(expr)
 * Can all be combined: dict.func(expr)[idx]['func'](expr)
 */
    int
handle_subscript(
    char_u	**arg,
    typval_T	*rettv,
    int		evaluate,	/* do more than finding the end */
    int		verbose)	/* give error messages */
{
    int		ret = OK;
    dict_T	*selfdict = NULL;
    char_u	*s;
    int		len;
    typval_T	functv;

    while (ret == OK
	    && (**arg == '['
		|| (**arg == '.' && rettv->v_type == VAR_DICT)
		|| (**arg == '(' && (!evaluate || rettv->v_type == VAR_FUNC
					    || rettv->v_type == VAR_PARTIAL)))
	    && !VIM_ISWHITE(*(*arg - 1)))
    {
	if (**arg == '(')
	{
	    partial_T	*pt = NULL;

	    /* need to copy the funcref so that we can clear rettv */
	    if (evaluate)
	    {
		functv = *rettv;
		rettv->v_type = VAR_UNKNOWN;

		/* Invoke the function.  Recursive! */
		if (functv.v_type == VAR_PARTIAL)
		{
		    pt = functv.vval.v_partial;
		    s = partial_name(pt);
		}
		else
		    s = functv.vval.v_string;
	    }
	    else
		s = (char_u *)"";
	    ret = get_func_tv(s, (int)STRLEN(s), rettv, arg,
			curwin->w_cursor.lnum, curwin->w_cursor.lnum,
			&len, evaluate, pt, selfdict);

	    /* Clear the funcref afterwards, so that deleting it while
	     * evaluating the arguments is possible (see test55). */
	    if (evaluate)
		clear_tv(&functv);

	    /* Stop the expression evaluation when immediately aborting on
	     * error, or when an interrupt occurred or an exception was thrown
	     * but not caught. */
	    if (aborting())
	    {
		if (ret == OK)
		    clear_tv(rettv);
		ret = FAIL;
	    }
	    dict_unref(selfdict);
	    selfdict = NULL;
	}
	else /* **arg == '[' || **arg == '.' */
	{
	    dict_unref(selfdict);
	    if (rettv->v_type == VAR_DICT)
	    {
		selfdict = rettv->vval.v_dict;
		if (selfdict != NULL)
		    ++selfdict->dv_refcount;
	    }
	    else
		selfdict = NULL;
	    if (eval_index(arg, rettv, evaluate, verbose) == FAIL)
	    {
		clear_tv(rettv);
		ret = FAIL;
	    }
	}
    }

    /* Turn "dict.Func" into a partial for "Func" bound to "dict".
     * Don't do this when "Func" is already a partial that was bound
     * explicitly (pt_auto is FALSE). */
    if (selfdict != NULL
	    && (rettv->v_type == VAR_FUNC
		|| (rettv->v_type == VAR_PARTIAL
		    && (rettv->vval.v_partial->pt_auto
			|| rettv->vval.v_partial->pt_dict == NULL))))
	selfdict = make_partial(selfdict, rettv);

    dict_unref(selfdict);
    return ret;
}

/*
 * Allocate memory for a variable type-value, and make it empty (0 or NULL
 * value).
 */
    typval_T *
alloc_tv(void)
{
    return (typval_T *)alloc_clear((unsigned)sizeof(typval_T));
}

/*
 * Allocate memory for a variable type-value, and assign a string to it.
 * The string "s" must have been allocated, it is consumed.
 * Return NULL for out of memory, the variable otherwise.
 */
    static typval_T *
alloc_string_tv(char_u *s)
{
    typval_T	*rettv;

    rettv = alloc_tv();
    if (rettv != NULL)
    {
	rettv->v_type = VAR_STRING;
	rettv->vval.v_string = s;
    }
    else
	vim_free(s);
    return rettv;
}

/*
 * Free the memory for a variable type-value.
 */
    void
free_tv(typval_T *varp)
{
    if (varp != NULL)
    {
	switch (varp->v_type)
	{
	    case VAR_FUNC:
		func_unref(varp->vval.v_string);
		/*FALLTHROUGH*/
	    case VAR_STRING:
		vim_free(varp->vval.v_string);
		break;
	    case VAR_PARTIAL:
		partial_unref(varp->vval.v_partial);
		break;
	    case VAR_LIST:
		list_unref(varp->vval.v_list);
		break;
	    case VAR_DICT:
		dict_unref(varp->vval.v_dict);
		break;
	    case VAR_JOB:
#ifdef FEAT_JOB_CHANNEL
		job_unref(varp->vval.v_job);
		break;
#endif
	    case VAR_CHANNEL:
#ifdef FEAT_JOB_CHANNEL
		channel_unref(varp->vval.v_channel);
		break;
#endif
	    case VAR_NUMBER:
	    case VAR_FLOAT:
	    case VAR_UNKNOWN:
	    case VAR_SPECIAL:
		break;
	}
	vim_free(varp);
    }
}

/*
 * Free the memory for a variable value and set the value to NULL or 0.
 */
    void
clear_tv(typval_T *varp)
{
    if (varp != NULL)
    {
	switch (varp->v_type)
	{
	    case VAR_FUNC:
		func_unref(varp->vval.v_string);
		/*FALLTHROUGH*/
	    case VAR_STRING:
		vim_free(varp->vval.v_string);
		varp->vval.v_string = NULL;
		break;
	    case VAR_PARTIAL:
		partial_unref(varp->vval.v_partial);
		varp->vval.v_partial = NULL;
		break;
	    case VAR_LIST:
		list_unref(varp->vval.v_list);
		varp->vval.v_list = NULL;
		break;
	    case VAR_DICT:
		dict_unref(varp->vval.v_dict);
		varp->vval.v_dict = NULL;
		break;
	    case VAR_NUMBER:
	    case VAR_SPECIAL:
		varp->vval.v_number = 0;
		break;
	    case VAR_FLOAT:
#ifdef FEAT_FLOAT
		varp->vval.v_float = 0.0;
		break;
#endif
	    case VAR_JOB:
#ifdef FEAT_JOB_CHANNEL
		job_unref(varp->vval.v_job);
		varp->vval.v_job = NULL;
#endif
		break;
	    case VAR_CHANNEL:
#ifdef FEAT_JOB_CHANNEL
		channel_unref(varp->vval.v_channel);
		varp->vval.v_channel = NULL;
#endif
	    case VAR_UNKNOWN:
		break;
	}
	varp->v_lock = 0;
    }
}

/*
 * Set the value of a variable to NULL without freeing items.
 */
    void
init_tv(typval_T *varp)
{
    if (varp != NULL)
	vim_memset(varp, 0, sizeof(typval_T));
}

/*
 * Get the number value of a variable.
 * If it is a String variable, uses vim_str2nr().
 * For incompatible types, return 0.
 * get_tv_number_chk() is similar to get_tv_number(), but informs the
 * caller of incompatible types: it sets *denote to TRUE if "denote"
 * is not NULL or returns -1 otherwise.
 */
    varnumber_T
get_tv_number(typval_T *varp)
{
    int		error = FALSE;

    return get_tv_number_chk(varp, &error);	/* return 0L on error */
}

    varnumber_T
get_tv_number_chk(typval_T *varp, int *denote)
{
    varnumber_T	n = 0L;

    switch (varp->v_type)
    {
	case VAR_NUMBER:
	    return varp->vval.v_number;
	case VAR_FLOAT:
#ifdef FEAT_FLOAT
	    EMSG(_("E805: Using a Float as a Number"));
	    break;
#endif
	case VAR_FUNC:
	case VAR_PARTIAL:
	    EMSG(_("E703: Using a Funcref as a Number"));
	    break;
	case VAR_STRING:
	    if (varp->vval.v_string != NULL)
		vim_str2nr(varp->vval.v_string, NULL, NULL,
						    STR2NR_ALL, &n, NULL, 0);
	    return n;
	case VAR_LIST:
	    EMSG(_("E745: Using a List as a Number"));
	    break;
	case VAR_DICT:
	    EMSG(_("E728: Using a Dictionary as a Number"));
	    break;
	case VAR_SPECIAL:
	    return varp->vval.v_number == VVAL_TRUE ? 1 : 0;
	    break;
	case VAR_JOB:
#ifdef FEAT_JOB_CHANNEL
	    EMSG(_("E910: Using a Job as a Number"));
	    break;
#endif
	case VAR_CHANNEL:
#ifdef FEAT_JOB_CHANNEL
	    EMSG(_("E913: Using a Channel as a Number"));
	    break;
#endif
	case VAR_UNKNOWN:
	    internal_error("get_tv_number(UNKNOWN)");
	    break;
    }
    if (denote == NULL)		/* useful for values that must be unsigned */
	n = -1;
    else
	*denote = TRUE;
    return n;
}

#ifdef FEAT_FLOAT
    float_T
get_tv_float(typval_T *varp)
{
    switch (varp->v_type)
    {
	case VAR_NUMBER:
	    return (float_T)(varp->vval.v_number);
	case VAR_FLOAT:
	    return varp->vval.v_float;
	case VAR_FUNC:
	case VAR_PARTIAL:
	    EMSG(_("E891: Using a Funcref as a Float"));
	    break;
	case VAR_STRING:
	    EMSG(_("E892: Using a String as a Float"));
	    break;
	case VAR_LIST:
	    EMSG(_("E893: Using a List as a Float"));
	    break;
	case VAR_DICT:
	    EMSG(_("E894: Using a Dictionary as a Float"));
	    break;
	case VAR_SPECIAL:
	    EMSG(_("E907: Using a special value as a Float"));
	    break;
	case VAR_JOB:
# ifdef FEAT_JOB_CHANNEL
	    EMSG(_("E911: Using a Job as a Float"));
	    break;
# endif
	case VAR_CHANNEL:
# ifdef FEAT_JOB_CHANNEL
	    EMSG(_("E914: Using a Channel as a Float"));
	    break;
# endif
	case VAR_UNKNOWN:
	    internal_error("get_tv_float(UNKNOWN)");
	    break;
    }
    return 0;
}
#endif

/*
 * Get the string value of a variable.
 * If it is a Number variable, the number is converted into a string.
 * get_tv_string() uses a single, static buffer.  YOU CAN ONLY USE IT ONCE!
 * get_tv_string_buf() uses a given buffer.
 * If the String variable has never been set, return an empty string.
 * Never returns NULL;
 * get_tv_string_chk() and get_tv_string_buf_chk() are similar, but return
 * NULL on error.
 */
    char_u *
get_tv_string(typval_T *varp)
{
    static char_u   mybuf[NUMBUFLEN];

    return get_tv_string_buf(varp, mybuf);
}

    char_u *
get_tv_string_buf(typval_T *varp, char_u *buf)
{
    char_u	*res =  get_tv_string_buf_chk(varp, buf);

    return res != NULL ? res : (char_u *)"";
}

/*
 * Careful: This uses a single, static buffer.  YOU CAN ONLY USE IT ONCE!
 */
    char_u *
get_tv_string_chk(typval_T *varp)
{
    static char_u   mybuf[NUMBUFLEN];

    return get_tv_string_buf_chk(varp, mybuf);
}

    char_u *
get_tv_string_buf_chk(typval_T *varp, char_u *buf)
{
    switch (varp->v_type)
    {
	case VAR_NUMBER:
	    vim_snprintf((char *)buf, NUMBUFLEN, "%lld",
					    (varnumber_T)varp->vval.v_number);
	    return buf;
	case VAR_FUNC:
	case VAR_PARTIAL:
	    EMSG(_("E729: using Funcref as a String"));
	    break;
	case VAR_LIST:
	    EMSG(_("E730: using List as a String"));
	    break;
	case VAR_DICT:
	    EMSG(_("E731: using Dictionary as a String"));
	    break;
	case VAR_FLOAT:
#ifdef FEAT_FLOAT
	    EMSG(_(e_float_as_string));
	    break;
#endif
	case VAR_STRING:
	    if (varp->vval.v_string != NULL)
		return varp->vval.v_string;
	    return (char_u *)"";
	case VAR_SPECIAL:
	    STRCPY(buf, get_var_special_name(varp->vval.v_number));
	    return buf;
	case VAR_JOB:
#ifdef FEAT_JOB_CHANNEL
	    {
		job_T *job = varp->vval.v_job;
		char  *status;

		if (job == NULL)
		    return (char_u *)"no process";
		status = job->jv_status == JOB_FAILED ? "fail"
				: job->jv_status >= JOB_ENDED ? "dead"
				: "run";
# ifdef UNIX
		vim_snprintf((char *)buf, NUMBUFLEN,
			    "process %ld %s", (long)job->jv_pid, status);
# elif defined(WIN32)
		vim_snprintf((char *)buf, NUMBUFLEN,
			    "process %ld %s",
			    (long)job->jv_proc_info.dwProcessId,
			    status);
# else
		/* fall-back */
		vim_snprintf((char *)buf, NUMBUFLEN, "process ? %s", status);
# endif
		return buf;
	    }
#endif
	    break;
	case VAR_CHANNEL:
#ifdef FEAT_JOB_CHANNEL
	    {
		channel_T *channel = varp->vval.v_channel;
		char      *status = channel_status(channel, -1);

		if (channel == NULL)
		    vim_snprintf((char *)buf, NUMBUFLEN, "channel %s", status);
		else
		    vim_snprintf((char *)buf, NUMBUFLEN,
				     "channel %d %s", channel->ch_id, status);
		return buf;
	    }
#endif
	    break;
	case VAR_UNKNOWN:
	    EMSG(_("E908: using an invalid value as a String"));
	    break;
    }
    return NULL;
}

/*
 * Find variable "name" in the list of variables.
 * Return a pointer to it if found, NULL if not found.
 * Careful: "a:0" variables don't have a name.
 * When "htp" is not NULL we are writing to the variable, set "htp" to the
 * hashtab_T used.
 */
    dictitem_T *
find_var(char_u *name, hashtab_T **htp, int no_autoload)
{
    char_u	*varname;
    hashtab_T	*ht;
    dictitem_T	*ret = NULL;

    ht = find_var_ht(name, &varname);
    if (htp != NULL)
	*htp = ht;
    if (ht == NULL)
	return NULL;
    ret = find_var_in_ht(ht, *name, varname, no_autoload || htp != NULL);
    if (ret != NULL)
	return ret;

    /* Search in parent scope for lambda */
    return find_var_in_scoped_ht(name, no_autoload || htp != NULL);
}

/*
 * Find variable "varname" in hashtab "ht" with name "htname".
 * Returns NULL if not found.
 */
    dictitem_T *
find_var_in_ht(
    hashtab_T	*ht,
    int		htname,
    char_u	*varname,
    int		no_autoload)
{
    hashitem_T	*hi;

    if (*varname == NUL)
    {
	/* Must be something like "s:", otherwise "ht" would be NULL. */
	switch (htname)
	{
	    case 's': return &SCRIPT_SV(current_SID)->sv_var;
	    case 'g': return &globvars_var;
	    case 'v': return &vimvars_var;
	    case 'b': return &curbuf->b_bufvar;
	    case 'w': return &curwin->w_winvar;
	    case 't': return &curtab->tp_winvar;
	    case 'l': return get_funccal_local_var();
	    case 'a': return get_funccal_args_var();
	}
	return NULL;
    }

    hi = hash_find(ht, varname);
    if (HASHITEM_EMPTY(hi))
    {
	/* For global variables we may try auto-loading the script.  If it
	 * worked find the variable again.  Don't auto-load a script if it was
	 * loaded already, otherwise it would be loaded every time when
	 * checking if a function name is a Funcref variable. */
	if (ht == &globvarht && !no_autoload)
	{
	    /* Note: script_autoload() may make "hi" invalid. It must either
	     * be obtained again or not used. */
	    if (!script_autoload(varname, FALSE) || aborting())
		return NULL;
	    hi = hash_find(ht, varname);
	}
	if (HASHITEM_EMPTY(hi))
	    return NULL;
    }
    return HI2DI(hi);
}

/*
 * Find the hashtab used for a variable name.
 * Return NULL if the name is not valid.
 * Set "varname" to the start of name without ':'.
 */
    hashtab_T *
find_var_ht(char_u *name, char_u **varname)
{
    hashitem_T	*hi;
    hashtab_T	*ht;

    if (name[0] == NUL)
	return NULL;
    if (name[1] != ':')
    {
	/* The name must not start with a colon or #. */
	if (name[0] == ':' || name[0] == AUTOLOAD_CHAR)
	    return NULL;
	*varname = name;

	/* "version" is "v:version" in all scopes */
	hi = hash_find(&compat_hashtab, name);
	if (!HASHITEM_EMPTY(hi))
	    return &compat_hashtab;

	ht = get_funccal_local_ht();
	if (ht == NULL)
	    return &globvarht;			/* global variable */
	return ht;				/* local variable */
    }
    *varname = name + 2;
    if (*name == 'g')				/* global variable */
	return &globvarht;
    /* There must be no ':' or '#' in the rest of the name, unless g: is used
     */
    if (vim_strchr(name + 2, ':') != NULL
			       || vim_strchr(name + 2, AUTOLOAD_CHAR) != NULL)
	return NULL;
    if (*name == 'b')				/* buffer variable */
	return &curbuf->b_vars->dv_hashtab;
    if (*name == 'w')				/* window variable */
	return &curwin->w_vars->dv_hashtab;
    if (*name == 't')				/* tab page variable */
	return &curtab->tp_vars->dv_hashtab;
    if (*name == 'v')				/* v: variable */
	return &vimvarht;
    if (*name == 'a')				/* a: function argument */
	return get_funccal_args_ht();
    if (*name == 'l')				/* l: local function variable */
	return get_funccal_local_ht();
    if (*name == 's'				/* script variable */
	    && current_SID > 0 && current_SID <= ga_scripts.ga_len)
	return &SCRIPT_VARS(current_SID);
    return NULL;
}

/*
 * Get the string value of a (global/local) variable.
 * Note: see get_tv_string() for how long the pointer remains valid.
 * Returns NULL when it doesn't exist.
 */
    char_u *
get_var_value(char_u *name)
{
    dictitem_T	*v;

    v = find_var(name, NULL, FALSE);
    if (v == NULL)
	return NULL;
    return get_tv_string(&v->di_tv);
}

/*
 * Allocate a new hashtab for a sourced script.  It will be used while
 * sourcing this script and when executing functions defined in the script.
 */
    void
new_script_vars(scid_T id)
{
    int		i;
    hashtab_T	*ht;
    scriptvar_T *sv;

    if (ga_grow(&ga_scripts, (int)(id - ga_scripts.ga_len)) == OK)
    {
	/* Re-allocating ga_data means that an ht_array pointing to
	 * ht_smallarray becomes invalid.  We can recognize this: ht_mask is
	 * at its init value.  Also reset "v_dict", it's always the same. */
	for (i = 1; i <= ga_scripts.ga_len; ++i)
	{
	    ht = &SCRIPT_VARS(i);
	    if (ht->ht_mask == HT_INIT_SIZE - 1)
		ht->ht_array = ht->ht_smallarray;
	    sv = SCRIPT_SV(i);
	    sv->sv_var.di_tv.vval.v_dict = &sv->sv_dict;
	}

	while (ga_scripts.ga_len < id)
	{
	    sv = SCRIPT_SV(ga_scripts.ga_len + 1) =
		(scriptvar_T *)alloc_clear(sizeof(scriptvar_T));
	    init_var_dict(&sv->sv_dict, &sv->sv_var, VAR_SCOPE);
	    ++ga_scripts.ga_len;
	}
    }
}

/*
 * Initialize dictionary "dict" as a scope and set variable "dict_var" to
 * point to it.
 */
    void
init_var_dict(dict_T *dict, dictitem_T *dict_var, int scope)
{
    hash_init(&dict->dv_hashtab);
    dict->dv_lock = 0;
    dict->dv_scope = scope;
    dict->dv_refcount = DO_NOT_FREE_CNT;
    dict->dv_copyID = 0;
    dict_var->di_tv.vval.v_dict = dict;
    dict_var->di_tv.v_type = VAR_DICT;
    dict_var->di_tv.v_lock = VAR_FIXED;
    dict_var->di_flags = DI_FLAGS_RO | DI_FLAGS_FIX;
    dict_var->di_key[0] = NUL;
}

/*
 * Unreference a dictionary initialized by init_var_dict().
 */
    void
unref_var_dict(dict_T *dict)
{
    /* Now the dict needs to be freed if no one else is using it, go back to
     * normal reference counting. */
    dict->dv_refcount -= DO_NOT_FREE_CNT - 1;
    dict_unref(dict);
}

/*
 * Clean up a list of internal variables.
 * Frees all allocated variables and the value they contain.
 * Clears hashtab "ht", does not free it.
 */
    void
vars_clear(hashtab_T *ht)
{
    vars_clear_ext(ht, TRUE);
}

/*
 * Like vars_clear(), but only free the value if "free_val" is TRUE.
 */
    void
vars_clear_ext(hashtab_T *ht, int free_val)
{
    int		todo;
    hashitem_T	*hi;
    dictitem_T	*v;

    hash_lock(ht);
    todo = (int)ht->ht_used;
    for (hi = ht->ht_array; todo > 0; ++hi)
    {
	if (!HASHITEM_EMPTY(hi))
	{
	    --todo;

	    /* Free the variable.  Don't remove it from the hashtab,
	     * ht_array might change then.  hash_clear() takes care of it
	     * later. */
	    v = HI2DI(hi);
	    if (free_val)
		clear_tv(&v->di_tv);
	    if (v->di_flags & DI_FLAGS_ALLOC)
		vim_free(v);
	}
    }
    hash_clear(ht);
    ht->ht_used = 0;
}

/*
 * Delete a variable from hashtab "ht" at item "hi".
 * Clear the variable value and free the dictitem.
 */
    static void
delete_var(hashtab_T *ht, hashitem_T *hi)
{
    dictitem_T	*di = HI2DI(hi);

    hash_remove(ht, hi);
    clear_tv(&di->di_tv);
    vim_free(di);
}

/*
 * List the value of one internal variable.
 */
    static void
list_one_var(dictitem_T *v, char_u *prefix, int *first)
{
    char_u	*tofree;
    char_u	*s;
    char_u	numbuf[NUMBUFLEN];

    s = echo_string(&v->di_tv, &tofree, numbuf, get_copyID());
    list_one_var_a(prefix, v->di_key, v->di_tv.v_type,
					 s == NULL ? (char_u *)"" : s, first);
    vim_free(tofree);
}

    static void
list_one_var_a(
    char_u	*prefix,
    char_u	*name,
    int		type,
    char_u	*string,
    int		*first)  /* when TRUE clear rest of screen and set to FALSE */
{
    /* don't use msg() or msg_attr() to avoid overwriting "v:statusmsg" */
    msg_start();
    msg_puts(prefix);
    if (name != NULL)	/* "a:" vars don't have a name stored */
	msg_puts(name);
    msg_putchar(' ');
    msg_advance(22);
    if (type == VAR_NUMBER)
	msg_putchar('#');
    else if (type == VAR_FUNC || type == VAR_PARTIAL)
	msg_putchar('*');
    else if (type == VAR_LIST)
    {
	msg_putchar('[');
	if (*string == '[')
	    ++string;
    }
    else if (type == VAR_DICT)
    {
	msg_putchar('{');
	if (*string == '{')
	    ++string;
    }
    else
	msg_putchar(' ');

    msg_outtrans(string);

    if (type == VAR_FUNC || type == VAR_PARTIAL)
	msg_puts((char_u *)"()");
    if (*first)
    {
	msg_clr_eos();
	*first = FALSE;
    }
}

/*
 * Set variable "name" to value in "tv".
 * If the variable already exists, the value is updated.
 * Otherwise the variable is created.
 */
    void
set_var(
    char_u	*name,
    typval_T	*tv,
    int		copy)	    /* make copy of value in "tv" */
{
    dictitem_T	*v;
    char_u	*varname;
    hashtab_T	*ht;

    ht = find_var_ht(name, &varname);
    if (ht == NULL || *varname == NUL)
    {
	EMSG2(_(e_illvar), name);
	return;
    }
    v = find_var_in_ht(ht, 0, varname, TRUE);

    /* Search in parent scope which is possible to reference from lambda */
    if (v == NULL)
	v = find_var_in_scoped_ht(name, TRUE);

    if ((tv->v_type == VAR_FUNC || tv->v_type == VAR_PARTIAL)
				      && var_check_func_name(name, v == NULL))
	return;

    if (v != NULL)
    {
	/* existing variable, need to clear the value */
	if (var_check_ro(v->di_flags, name, FALSE)
			       || tv_check_lock(v->di_tv.v_lock, name, FALSE))
	    return;

	/*
	 * Handle setting internal v: variables separately where needed to
	 * prevent changing the type.
	 */
	if (ht == &vimvarht)
	{
	    if (v->di_tv.v_type == VAR_STRING)
	    {
		vim_free(v->di_tv.vval.v_string);
		if (copy || tv->v_type != VAR_STRING)
		    v->di_tv.vval.v_string = vim_strsave(get_tv_string(tv));
		else
		{
		    /* Take over the string to avoid an extra alloc/free. */
		    v->di_tv.vval.v_string = tv->vval.v_string;
		    tv->vval.v_string = NULL;
		}
		return;
	    }
	    else if (v->di_tv.v_type == VAR_NUMBER)
	    {
		v->di_tv.vval.v_number = get_tv_number(tv);
		if (STRCMP(varname, "searchforward") == 0)
		    set_search_direction(v->di_tv.vval.v_number ? '/' : '?');
#ifdef FEAT_SEARCH_EXTRA
		else if (STRCMP(varname, "hlsearch") == 0)
		{
		    no_hlsearch = !v->di_tv.vval.v_number;
		    redraw_all_later(SOME_VALID);
		}
#endif
		return;
	    }
	    else if (v->di_tv.v_type != tv->v_type)
		internal_error("set_var()");
	}

	clear_tv(&v->di_tv);
    }
    else		    /* add a new variable */
    {
	/* Can't add "v:" variable. */
	if (ht == &vimvarht)
	{
	    EMSG2(_(e_illvar), name);
	    return;
	}

	/* Make sure the variable name is valid. */
	if (!valid_varname(varname))
	    return;

	v = (dictitem_T *)alloc((unsigned)(sizeof(dictitem_T)
							  + STRLEN(varname)));
	if (v == NULL)
	    return;
	STRCPY(v->di_key, varname);
	if (hash_add(ht, DI2HIKEY(v)) == FAIL)
	{
	    vim_free(v);
	    return;
	}
	v->di_flags = DI_FLAGS_ALLOC;
    }

    if (copy || tv->v_type == VAR_NUMBER || tv->v_type == VAR_FLOAT)
	copy_tv(tv, &v->di_tv);
    else
    {
	v->di_tv = *tv;
	v->di_tv.v_lock = 0;
	init_tv(tv);
    }
}

/*
 * Return TRUE if di_flags "flags" indicates variable "name" is read-only.
 * Also give an error message.
 */
    int
var_check_ro(int flags, char_u *name, int use_gettext)
{
    if (flags & DI_FLAGS_RO)
    {
	EMSG2(_(e_readonlyvar), use_gettext ? (char_u *)_(name) : name);
	return TRUE;
    }
    if ((flags & DI_FLAGS_RO_SBX) && sandbox)
    {
	EMSG2(_(e_readonlysbx), use_gettext ? (char_u *)_(name) : name);
	return TRUE;
    }
    return FALSE;
}

/*
 * Return TRUE if di_flags "flags" indicates variable "name" is fixed.
 * Also give an error message.
 */
    int
var_check_fixed(int flags, char_u *name, int use_gettext)
{
    if (flags & DI_FLAGS_FIX)
    {
	EMSG2(_("E795: Cannot delete variable %s"),
				      use_gettext ? (char_u *)_(name) : name);
	return TRUE;
    }
    return FALSE;
}

/*
 * Check if a funcref is assigned to a valid variable name.
 * Return TRUE and give an error if not.
 */
    int
var_check_func_name(
    char_u *name,    /* points to start of variable name */
    int    new_var)  /* TRUE when creating the variable */
{
    /* Allow for w: b: s: and t:. */
    if (!(vim_strchr((char_u *)"wbst", name[0]) != NULL && name[1] == ':')
	    && !ASCII_ISUPPER((name[0] != NUL && name[1] == ':')
						     ? name[2] : name[0]))
    {
	EMSG2(_("E704: Funcref variable name must start with a capital: %s"),
									name);
	return TRUE;
    }
    /* Don't allow hiding a function.  When "v" is not NULL we might be
     * assigning another function to the same var, the type is checked
     * below. */
    if (new_var && function_exists(name, FALSE))
    {
	EMSG2(_("E705: Variable name conflicts with existing function: %s"),
								    name);
	return TRUE;
    }
    return FALSE;
}

/*
 * Check if a variable name is valid.
 * Return FALSE and give an error if not.
 */
    int
valid_varname(char_u *varname)
{
    char_u *p;

    for (p = varname; *p != NUL; ++p)
	if (!eval_isnamec1(*p) && (p == varname || !VIM_ISDIGIT(*p))
						   && *p != AUTOLOAD_CHAR)
	{
	    EMSG2(_(e_illvar), varname);
	    return FALSE;
	}
    return TRUE;
}

/*
 * Return TRUE if typeval "tv" is set to be locked (immutable).
 * Also give an error message, using "name" or _("name") when use_gettext is
 * TRUE.
 */
    int
tv_check_lock(int lock, char_u *name, int use_gettext)
{
    if (lock & VAR_LOCKED)
    {
	EMSG2(_("E741: Value is locked: %s"),
				name == NULL ? (char_u *)_("Unknown")
					     : use_gettext ? (char_u *)_(name)
					     : name);
	return TRUE;
    }
    if (lock & VAR_FIXED)
    {
	EMSG2(_("E742: Cannot change value of %s"),
				name == NULL ? (char_u *)_("Unknown")
					     : use_gettext ? (char_u *)_(name)
					     : name);
	return TRUE;
    }
    return FALSE;
}

/*
 * Copy the values from typval_T "from" to typval_T "to".
 * When needed allocates string or increases reference count.
 * Does not make a copy of a list or dict but copies the reference!
 * It is OK for "from" and "to" to point to the same item.  This is used to
 * make a copy later.
 */
    void
copy_tv(typval_T *from, typval_T *to)
{
    to->v_type = from->v_type;
    to->v_lock = 0;
    switch (from->v_type)
    {
	case VAR_NUMBER:
	case VAR_SPECIAL:
	    to->vval.v_number = from->vval.v_number;
	    break;
	case VAR_FLOAT:
#ifdef FEAT_FLOAT
	    to->vval.v_float = from->vval.v_float;
	    break;
#endif
	case VAR_JOB:
#ifdef FEAT_JOB_CHANNEL
	    to->vval.v_job = from->vval.v_job;
	    if (to->vval.v_job != NULL)
		++to->vval.v_job->jv_refcount;
	    break;
#endif
	case VAR_CHANNEL:
#ifdef FEAT_JOB_CHANNEL
	    to->vval.v_channel = from->vval.v_channel;
	    if (to->vval.v_channel != NULL)
		++to->vval.v_channel->ch_refcount;
	    break;
#endif
	case VAR_STRING:
	case VAR_FUNC:
	    if (from->vval.v_string == NULL)
		to->vval.v_string = NULL;
	    else
	    {
		to->vval.v_string = vim_strsave(from->vval.v_string);
		if (from->v_type == VAR_FUNC)
		    func_ref(to->vval.v_string);
	    }
	    break;
	case VAR_PARTIAL:
	    if (from->vval.v_partial == NULL)
		to->vval.v_partial = NULL;
	    else
	    {
		to->vval.v_partial = from->vval.v_partial;
		++to->vval.v_partial->pt_refcount;
	    }
	    break;
	case VAR_LIST:
	    if (from->vval.v_list == NULL)
		to->vval.v_list = NULL;
	    else
	    {
		to->vval.v_list = from->vval.v_list;
		++to->vval.v_list->lv_refcount;
	    }
	    break;
	case VAR_DICT:
	    if (from->vval.v_dict == NULL)
		to->vval.v_dict = NULL;
	    else
	    {
		to->vval.v_dict = from->vval.v_dict;
		++to->vval.v_dict->dv_refcount;
	    }
	    break;
	case VAR_UNKNOWN:
	    internal_error("copy_tv(UNKNOWN)");
	    break;
    }
}

/*
 * Make a copy of an item.
 * Lists and Dictionaries are also copied.  A deep copy if "deep" is set.
 * For deepcopy() "copyID" is zero for a full copy or the ID for when a
 * reference to an already copied list/dict can be used.
 * Returns FAIL or OK.
 */
    int
item_copy(
    typval_T	*from,
    typval_T	*to,
    int		deep,
    int		copyID)
{
    static int	recurse = 0;
    int		ret = OK;

    if (recurse >= DICT_MAXNEST)
    {
	EMSG(_("E698: variable nested too deep for making a copy"));
	return FAIL;
    }
    ++recurse;

    switch (from->v_type)
    {
	case VAR_NUMBER:
	case VAR_FLOAT:
	case VAR_STRING:
	case VAR_FUNC:
	case VAR_PARTIAL:
	case VAR_SPECIAL:
	case VAR_JOB:
	case VAR_CHANNEL:
	    copy_tv(from, to);
	    break;
	case VAR_LIST:
	    to->v_type = VAR_LIST;
	    to->v_lock = 0;
	    if (from->vval.v_list == NULL)
		to->vval.v_list = NULL;
	    else if (copyID != 0 && from->vval.v_list->lv_copyID == copyID)
	    {
		/* use the copy made earlier */
		to->vval.v_list = from->vval.v_list->lv_copylist;
		++to->vval.v_list->lv_refcount;
	    }
	    else
		to->vval.v_list = list_copy(from->vval.v_list, deep, copyID);
	    if (to->vval.v_list == NULL)
		ret = FAIL;
	    break;
	case VAR_DICT:
	    to->v_type = VAR_DICT;
	    to->v_lock = 0;
	    if (from->vval.v_dict == NULL)
		to->vval.v_dict = NULL;
	    else if (copyID != 0 && from->vval.v_dict->dv_copyID == copyID)
	    {
		/* use the copy made earlier */
		to->vval.v_dict = from->vval.v_dict->dv_copydict;
		++to->vval.v_dict->dv_refcount;
	    }
	    else
		to->vval.v_dict = dict_copy(from->vval.v_dict, deep, copyID);
	    if (to->vval.v_dict == NULL)
		ret = FAIL;
	    break;
	case VAR_UNKNOWN:
	    internal_error("item_copy(UNKNOWN)");
	    ret = FAIL;
    }
    --recurse;
    return ret;
}

/*
 * This function is used by f_input() and f_inputdialog() functions. The third
 * argument to f_input() specifies the type of completion to use at the
 * prompt. The third argument to f_inputdialog() specifies the value to return
 * when the user cancels the prompt.
 */
    void
get_user_input(
    typval_T	*argvars,
    typval_T	*rettv,
    int		inputdialog,
    int		secret)
{
    char_u	*prompt = get_tv_string_chk(&argvars[0]);
    char_u	*p = NULL;
    int		c;
    char_u	buf[NUMBUFLEN];
    int		cmd_silent_save = cmd_silent;
    char_u	*defstr = (char_u *)"";
    int		xp_type = EXPAND_NOTHING;
    char_u	*xp_arg = NULL;

    rettv->v_type = VAR_STRING;
    rettv->vval.v_string = NULL;

#ifdef NO_CONSOLE_INPUT
    /* While starting up, there is no place to enter text. When running tests
     * with --not-a-term we assume feedkeys() will be used. */
    if (no_console_input() && !is_not_a_term())
	return;
#endif

    cmd_silent = FALSE;		/* Want to see the prompt. */
    if (prompt != NULL)
    {
	/* Only the part of the message after the last NL is considered as
	 * prompt for the command line */
	p = vim_strrchr(prompt, '\n');
	if (p == NULL)
	    p = prompt;
	else
	{
	    ++p;
	    c = *p;
	    *p = NUL;
	    msg_start();
	    msg_clr_eos();
	    msg_puts_attr(prompt, echo_attr);
	    msg_didout = FALSE;
	    msg_starthere();
	    *p = c;
	}
	cmdline_row = msg_row;

	if (argvars[1].v_type != VAR_UNKNOWN)
	{
	    defstr = get_tv_string_buf_chk(&argvars[1], buf);
	    if (defstr != NULL)
		stuffReadbuffSpec(defstr);

	    if (!inputdialog && argvars[2].v_type != VAR_UNKNOWN)
	    {
		char_u	*xp_name;
		int	xp_namelen;
		long	argt;

		/* input() with a third argument: completion */
		rettv->vval.v_string = NULL;

		xp_name = get_tv_string_buf_chk(&argvars[2], buf);
		if (xp_name == NULL)
		    return;

		xp_namelen = (int)STRLEN(xp_name);

		if (parse_compl_arg(xp_name, xp_namelen, &xp_type, &argt,
							     &xp_arg) == FAIL)
		    return;
	    }
	}

	if (defstr != NULL)
	{
	    int save_ex_normal_busy = ex_normal_busy;
	    ex_normal_busy = 0;
	    rettv->vval.v_string =
		getcmdline_prompt(secret ? NUL : '@', p, echo_attr,
							      xp_type, xp_arg);
	    ex_normal_busy = save_ex_normal_busy;
	}
	if (inputdialog && rettv->vval.v_string == NULL
		&& argvars[1].v_type != VAR_UNKNOWN
		&& argvars[2].v_type != VAR_UNKNOWN)
	    rettv->vval.v_string = vim_strsave(get_tv_string_buf(
							   &argvars[2], buf));

	vim_free(xp_arg);

	/* since the user typed this, no need to wait for return */
	need_wait_return = FALSE;
	msg_didout = FALSE;
    }
    cmd_silent = cmd_silent_save;
}

/*
 * ":echo expr1 ..."	print each argument separated with a space, add a
 *			newline at the end.
 * ":echon expr1 ..."	print each argument plain.
 */
    void
ex_echo(exarg_T *eap)
{
    char_u	*arg = eap->arg;
    typval_T	rettv;
    char_u	*tofree;
    char_u	*p;
    int		needclr = TRUE;
    int		atstart = TRUE;
    char_u	numbuf[NUMBUFLEN];

    if (eap->skip)
	++emsg_skip;
    while (*arg != NUL && *arg != '|' && *arg != '\n' && !got_int)
    {
	/* If eval1() causes an error message the text from the command may
	 * still need to be cleared. E.g., "echo 22,44". */
	need_clr_eos = needclr;

	p = arg;
	if (eval1(&arg, &rettv, !eap->skip) == FAIL)
	{
	    /*
	     * Report the invalid expression unless the expression evaluation
	     * has been cancelled due to an aborting error, an interrupt, or an
	     * exception.
	     */
	    if (!aborting())
		EMSG2(_(e_invexpr2), p);
	    need_clr_eos = FALSE;
	    break;
	}
	need_clr_eos = FALSE;

	if (!eap->skip)
	{
	    if (atstart)
	    {
		atstart = FALSE;
		/* Call msg_start() after eval1(), evaluating the expression
		 * may cause a message to appear. */
		if (eap->cmdidx == CMD_echo)
		{
		    /* Mark the saved text as finishing the line, so that what
		     * follows is displayed on a new line when scrolling back
		     * at the more prompt. */
		    msg_sb_eol();
		    msg_start();
		}
	    }
	    else if (eap->cmdidx == CMD_echo)
		msg_puts_attr((char_u *)" ", echo_attr);
	    p = echo_string(&rettv, &tofree, numbuf, get_copyID());
	    if (p != NULL)
		for ( ; *p != NUL && !got_int; ++p)
		{
		    if (*p == '\n' || *p == '\r' || *p == TAB)
		    {
			if (*p != TAB && needclr)
			{
			    /* remove any text still there from the command */
			    msg_clr_eos();
			    needclr = FALSE;
			}
			msg_putchar_attr(*p, echo_attr);
		    }
		    else
		    {
#ifdef FEAT_MBYTE
			if (has_mbyte)
			{
			    int i = (*mb_ptr2len)(p);

			    (void)msg_outtrans_len_attr(p, i, echo_attr);
			    p += i - 1;
			}
			else
#endif
			    (void)msg_outtrans_len_attr(p, 1, echo_attr);
		    }
		}
	    vim_free(tofree);
	}
	clear_tv(&rettv);
	arg = skipwhite(arg);
    }
    eap->nextcmd = check_nextcmd(arg);

    if (eap->skip)
	--emsg_skip;
    else
    {
	/* remove text that may still be there from the command */
	if (needclr)
	    msg_clr_eos();
	if (eap->cmdidx == CMD_echo)
	    msg_end();
    }
}

/*
 * ":echohl {name}".
 */
    void
ex_echohl(exarg_T *eap)
{
    int		id;

    id = syn_name2id(eap->arg);
    if (id == 0)
	echo_attr = 0;
    else
	echo_attr = syn_id2attr(id);
}

/*
 * ":execute expr1 ..."	execute the result of an expression.
 * ":echomsg expr1 ..."	Print a message
 * ":echoerr expr1 ..."	Print an error
 * Each gets spaces around each argument and a newline at the end for
 * echo commands
 */
    void
ex_execute(exarg_T *eap)
{
    char_u	*arg = eap->arg;
    typval_T	rettv;
    int		ret = OK;
    char_u	*p;
    garray_T	ga;
    int		len;
    int		save_did_emsg;

    ga_init2(&ga, 1, 80);

    if (eap->skip)
	++emsg_skip;
    while (*arg != NUL && *arg != '|' && *arg != '\n')
    {
	p = arg;
	if (eval1(&arg, &rettv, !eap->skip) == FAIL)
	{
	    /*
	     * Report the invalid expression unless the expression evaluation
	     * has been cancelled due to an aborting error, an interrupt, or an
	     * exception.
	     */
	    if (!aborting())
		EMSG2(_(e_invexpr2), p);
	    ret = FAIL;
	    break;
	}

	if (!eap->skip)
	{
	    p = get_tv_string(&rettv);
	    len = (int)STRLEN(p);
	    if (ga_grow(&ga, len + 2) == FAIL)
	    {
		clear_tv(&rettv);
		ret = FAIL;
		break;
	    }
	    if (ga.ga_len)
		((char_u *)(ga.ga_data))[ga.ga_len++] = ' ';
	    STRCPY((char_u *)(ga.ga_data) + ga.ga_len, p);
	    ga.ga_len += len;
	}

	clear_tv(&rettv);
	arg = skipwhite(arg);
    }

    if (ret != FAIL && ga.ga_data != NULL)
    {
	if (eap->cmdidx == CMD_echomsg || eap->cmdidx == CMD_echoerr)
	{
	    /* Mark the already saved text as finishing the line, so that what
	     * follows is displayed on a new line when scrolling back at the
	     * more prompt. */
	    msg_sb_eol();
	}

	if (eap->cmdidx == CMD_echomsg)
	{
	    MSG_ATTR(ga.ga_data, echo_attr);
	    out_flush();
	}
	else if (eap->cmdidx == CMD_echoerr)
	{
	    /* We don't want to abort following commands, restore did_emsg. */
	    save_did_emsg = did_emsg;
	    EMSG((char_u *)ga.ga_data);
	    if (!force_abort)
		did_emsg = save_did_emsg;
	}
	else if (eap->cmdidx == CMD_execute)
	    do_cmdline((char_u *)ga.ga_data,
		       eap->getline, eap->cookie, DOCMD_NOWAIT|DOCMD_VERBOSE);
    }

    ga_clear(&ga);

    if (eap->skip)
	--emsg_skip;

    eap->nextcmd = check_nextcmd(arg);
}

/*
 * Find window specified by "vp" in tabpage "tp".
 */
    win_T *
find_win_by_nr(
    typval_T	*vp,
    tabpage_T	*tp UNUSED)	/* NULL for current tab page */
{
    win_T	*wp;
    int		nr;

    nr = (int)get_tv_number_chk(vp, NULL);

    if (nr < 0)
	return NULL;
    if (nr == 0)
	return curwin;

    FOR_ALL_WINDOWS_IN_TAB(tp, wp)
    {
	if (nr >= LOWEST_WIN_ID)
	{
	    if (wp->w_id == nr)
		return wp;
	}
	else if (--nr <= 0)
	    break;
    }
    if (nr >= LOWEST_WIN_ID)
	return NULL;
    return wp;
}

/*
 * Find window specified by "wvp" in tabpage "tvp".
 */
    win_T *
find_tabwin(
    typval_T	*wvp,	/* VAR_UNKNOWN for current window */
    typval_T	*tvp)	/* VAR_UNKNOWN for current tab page */
{
    win_T	*wp = NULL;
    tabpage_T	*tp = NULL;
    long	n;

    if (wvp->v_type != VAR_UNKNOWN)
    {
	if (tvp->v_type != VAR_UNKNOWN)
	{
	    n = (long)get_tv_number(tvp);
	    if (n >= 0)
		tp = find_tabpage(n);
	}
	else
	    tp = curtab;

	if (tp != NULL)
	    wp = find_win_by_nr(wvp, tp);
    }
    else
	wp = curwin;

    return wp;
}

/*
 * getwinvar() and gettabwinvar()
 */
    void
getwinvar(
    typval_T	*argvars,
    typval_T	*rettv,
    int		off)	    /* 1 for gettabwinvar() */
{
    win_T	*win;
    char_u	*varname;
    dictitem_T	*v;
    tabpage_T	*tp = NULL;
    int		done = FALSE;
    win_T	*oldcurwin;
    tabpage_T	*oldtabpage;
    int		need_switch_win;

    if (off == 1)
	tp = find_tabpage((int)get_tv_number_chk(&argvars[0], NULL));
    else
	tp = curtab;
    win = find_win_by_nr(&argvars[off], tp);
    varname = get_tv_string_chk(&argvars[off + 1]);
    ++emsg_off;

    rettv->v_type = VAR_STRING;
    rettv->vval.v_string = NULL;

    if (win != NULL && varname != NULL)
    {
	/* Set curwin to be our win, temporarily.  Also set the tabpage,
	 * otherwise the window is not valid. Only do this when needed,
	 * autocommands get blocked. */
	need_switch_win = !(tp == curtab && win == curwin);
	if (!need_switch_win
		  || switch_win(&oldcurwin, &oldtabpage, win, tp, TRUE) == OK)
	{
	    if (*varname == '&')
	    {
		if (varname[1] == NUL)
		{
		    /* get all window-local options in a dict */
		    dict_T	*opts = get_winbuf_options(FALSE);

		    if (opts != NULL)
		    {
			rettv_dict_set(rettv, opts);
			done = TRUE;
		    }
		}
		else if (get_option_tv(&varname, rettv, 1) == OK)
		    /* window-local-option */
		    done = TRUE;
	    }
	    else
	    {
		/* Look up the variable. */
		/* Let getwinvar({nr}, "") return the "w:" dictionary. */
		v = find_var_in_ht(&win->w_vars->dv_hashtab, 'w',
							      varname, FALSE);
		if (v != NULL)
		{
		    copy_tv(&v->di_tv, rettv);
		    done = TRUE;
		}
	    }
	}

	if (need_switch_win)
	    /* restore previous notion of curwin */
	    restore_win(oldcurwin, oldtabpage, TRUE);
    }

    if (!done && argvars[off + 2].v_type != VAR_UNKNOWN)
	/* use the default return value */
	copy_tv(&argvars[off + 2], rettv);

    --emsg_off;
}

/*
 * "setwinvar()" and "settabwinvar()" functions
 */
    void
setwinvar(typval_T *argvars, typval_T *rettv UNUSED, int off)
{
    win_T	*win;
    win_T	*save_curwin;
    tabpage_T	*save_curtab;
    int		need_switch_win;
    char_u	*varname, *winvarname;
    typval_T	*varp;
    char_u	nbuf[NUMBUFLEN];
    tabpage_T	*tp = NULL;

    if (check_restricted() || check_secure())
	return;

    if (off == 1)
	tp = find_tabpage((int)get_tv_number_chk(&argvars[0], NULL));
    else
	tp = curtab;
    win = find_win_by_nr(&argvars[off], tp);
    varname = get_tv_string_chk(&argvars[off + 1]);
    varp = &argvars[off + 2];

    if (win != NULL && varname != NULL && varp != NULL)
    {
	need_switch_win = !(tp == curtab && win == curwin);
	if (!need_switch_win
	       || switch_win(&save_curwin, &save_curtab, win, tp, TRUE) == OK)
	{
	    if (*varname == '&')
	    {
		long	numval;
		char_u	*strval;
		int		error = FALSE;

		++varname;
		numval = (long)get_tv_number_chk(varp, &error);
		strval = get_tv_string_buf_chk(varp, nbuf);
		if (!error && strval != NULL)
		    set_option_value(varname, numval, strval, OPT_LOCAL);
	    }
	    else
	    {
		winvarname = alloc((unsigned)STRLEN(varname) + 3);
		if (winvarname != NULL)
		{
		    STRCPY(winvarname, "w:");
		    STRCPY(winvarname + 2, varname);
		    set_var(winvarname, varp, TRUE);
		    vim_free(winvarname);
		}
	    }
	}
	if (need_switch_win)
	    restore_win(save_curwin, save_curtab, TRUE);
    }
}

/*
 * Skip over the name of an option: "&option", "&g:option" or "&l:option".
 * "arg" points to the "&" or '+' when called, to "option" when returning.
 * Returns NULL when no option name found.  Otherwise pointer to the char
 * after the option name.
 */
    static char_u *
find_option_end(char_u **arg, int *opt_flags)
{
    char_u	*p = *arg;

    ++p;
    if (*p == 'g' && p[1] == ':')
    {
	*opt_flags = OPT_GLOBAL;
	p += 2;
    }
    else if (*p == 'l' && p[1] == ':')
    {
	*opt_flags = OPT_LOCAL;
	p += 2;
    }
    else
	*opt_flags = 0;

    if (!ASCII_ISALPHA(*p))
	return NULL;
    *arg = p;

    if (p[0] == 't' && p[1] == '_' && p[2] != NUL && p[3] != NUL)
	p += 4;	    /* termcap option */
    else
	while (ASCII_ISALPHA(*p))
	    ++p;
    return p;
}

/*
 * Return the autoload script name for a function or variable name.
 * Returns NULL when out of memory.
 */
    char_u *
autoload_name(char_u *name)
{
    char_u	*p;
    char_u	*scriptname;

    /* Get the script file name: replace '#' with '/', append ".vim". */
    scriptname = alloc((unsigned)(STRLEN(name) + 14));
    if (scriptname == NULL)
	return FALSE;
    STRCPY(scriptname, "autoload/");
    STRCAT(scriptname, name);
    *vim_strrchr(scriptname, AUTOLOAD_CHAR) = NUL;
    STRCAT(scriptname, ".vim");
    while ((p = vim_strchr(scriptname, AUTOLOAD_CHAR)) != NULL)
	*p = '/';
    return scriptname;
}

/*
 * If "name" has a package name try autoloading the script for it.
 * Return TRUE if a package was loaded.
 */
    int
script_autoload(
    char_u	*name,
    int		reload)	    /* load script again when already loaded */
{
    char_u	*p;
    char_u	*scriptname, *tofree;
    int		ret = FALSE;
    int		i;

    /* If there is no '#' after name[0] there is no package name. */
    p = vim_strchr(name, AUTOLOAD_CHAR);
    if (p == NULL || p == name)
	return FALSE;

    tofree = scriptname = autoload_name(name);

    /* Find the name in the list of previously loaded package names.  Skip
     * "autoload/", it's always the same. */
    for (i = 0; i < ga_loaded.ga_len; ++i)
	if (STRCMP(((char_u **)ga_loaded.ga_data)[i] + 9, scriptname + 9) == 0)
	    break;
    if (!reload && i < ga_loaded.ga_len)
	ret = FALSE;	    /* was loaded already */
    else
    {
	/* Remember the name if it wasn't loaded already. */
	if (i == ga_loaded.ga_len && ga_grow(&ga_loaded, 1) == OK)
	{
	    ((char_u **)ga_loaded.ga_data)[ga_loaded.ga_len++] = scriptname;
	    tofree = NULL;
	}

	/* Try loading the package from $VIMRUNTIME/autoload/<name>.vim */
	if (source_runtime(scriptname, 0) == OK)
	    ret = TRUE;
    }

    vim_free(tofree);
    return ret;
}

#if defined(FEAT_VIMINFO) || defined(FEAT_SESSION)
typedef enum
{
    VAR_FLAVOUR_DEFAULT,	/* doesn't start with uppercase */
    VAR_FLAVOUR_SESSION,	/* starts with uppercase, some lower */
    VAR_FLAVOUR_VIMINFO		/* all uppercase */
} var_flavour_T;

static var_flavour_T var_flavour(char_u *varname);

    static var_flavour_T
var_flavour(char_u *varname)
{
    char_u *p = varname;

    if (ASCII_ISUPPER(*p))
    {
	while (*(++p))
	    if (ASCII_ISLOWER(*p))
		return VAR_FLAVOUR_SESSION;
	return VAR_FLAVOUR_VIMINFO;
    }
    else
	return VAR_FLAVOUR_DEFAULT;
}
#endif

#if defined(FEAT_VIMINFO) || defined(PROTO)
/*
 * Restore global vars that start with a capital from the viminfo file
 */
    int
read_viminfo_varlist(vir_T *virp, int writing)
{
    char_u	*tab;
    int		type = VAR_NUMBER;
    typval_T	tv;
    void	*save_funccal;

    if (!writing && (find_viminfo_parameter('!') != NULL))
    {
	tab = vim_strchr(virp->vir_line + 1, '\t');
	if (tab != NULL)
	{
	    *tab++ = '\0';	/* isolate the variable name */
	    switch (*tab)
	    {
		case 'S': type = VAR_STRING; break;
#ifdef FEAT_FLOAT
		case 'F': type = VAR_FLOAT; break;
#endif
		case 'D': type = VAR_DICT; break;
		case 'L': type = VAR_LIST; break;
		case 'X': type = VAR_SPECIAL; break;
	    }

	    tab = vim_strchr(tab, '\t');
	    if (tab != NULL)
	    {
		tv.v_type = type;
		if (type == VAR_STRING || type == VAR_DICT || type == VAR_LIST)
		    tv.vval.v_string = viminfo_readstring(virp,
				       (int)(tab - virp->vir_line + 1), TRUE);
#ifdef FEAT_FLOAT
		else if (type == VAR_FLOAT)
		    (void)string2float(tab + 1, &tv.vval.v_float);
#endif
		else
		    tv.vval.v_number = atol((char *)tab + 1);
		if (type == VAR_DICT || type == VAR_LIST)
		{
		    typval_T *etv = eval_expr(tv.vval.v_string, NULL);

		    if (etv == NULL)
			/* Failed to parse back the dict or list, use it as a
			 * string. */
			tv.v_type = VAR_STRING;
		    else
		    {
			vim_free(tv.vval.v_string);
			tv = *etv;
			vim_free(etv);
		    }
		}

		/* when in a function use global variables */
		save_funccal = clear_current_funccal();
		set_var(virp->vir_line + 1, &tv, FALSE);
		restore_current_funccal(save_funccal);

		if (tv.v_type == VAR_STRING)
		    vim_free(tv.vval.v_string);
		else if (tv.v_type == VAR_DICT || tv.v_type == VAR_LIST)
		    clear_tv(&tv);
	    }
	}
    }

    return viminfo_readline(virp);
}

/*
 * Write global vars that start with a capital to the viminfo file
 */
    void
write_viminfo_varlist(FILE *fp)
{
    hashitem_T	*hi;
    dictitem_T	*this_var;
    int		todo;
    char	*s = "";
    char_u	*p;
    char_u	*tofree;
    char_u	numbuf[NUMBUFLEN];

    if (find_viminfo_parameter('!') == NULL)
	return;

    fputs(_("\n# global variables:\n"), fp);

    todo = (int)globvarht.ht_used;
    for (hi = globvarht.ht_array; todo > 0; ++hi)
    {
	if (!HASHITEM_EMPTY(hi))
	{
	    --todo;
	    this_var = HI2DI(hi);
	    if (var_flavour(this_var->di_key) == VAR_FLAVOUR_VIMINFO)
	    {
		switch (this_var->di_tv.v_type)
		{
		    case VAR_STRING: s = "STR"; break;
		    case VAR_NUMBER: s = "NUM"; break;
		    case VAR_FLOAT:  s = "FLO"; break;
		    case VAR_DICT:   s = "DIC"; break;
		    case VAR_LIST:   s = "LIS"; break;
		    case VAR_SPECIAL: s = "XPL"; break;

		    case VAR_UNKNOWN:
		    case VAR_FUNC:
		    case VAR_PARTIAL:
		    case VAR_JOB:
		    case VAR_CHANNEL:
				     continue;
		}
		fprintf(fp, "!%s\t%s\t", this_var->di_key, s);
		p = echo_string(&this_var->di_tv, &tofree, numbuf, 0);
		if (p != NULL)
		    viminfo_writestring(fp, p);
		vim_free(tofree);
	    }
	}
    }
}
#endif

#if defined(FEAT_SESSION) || defined(PROTO)
    int
store_session_globals(FILE *fd)
{
    hashitem_T	*hi;
    dictitem_T	*this_var;
    int		todo;
    char_u	*p, *t;

    todo = (int)globvarht.ht_used;
    for (hi = globvarht.ht_array; todo > 0; ++hi)
    {
	if (!HASHITEM_EMPTY(hi))
	{
	    --todo;
	    this_var = HI2DI(hi);
	    if ((this_var->di_tv.v_type == VAR_NUMBER
			|| this_var->di_tv.v_type == VAR_STRING)
		    && var_flavour(this_var->di_key) == VAR_FLAVOUR_SESSION)
	    {
		/* Escape special characters with a backslash.  Turn a LF and
		 * CR into \n and \r. */
		p = vim_strsave_escaped(get_tv_string(&this_var->di_tv),
							(char_u *)"\\\"\n\r");
		if (p == NULL)	    /* out of memory */
		    break;
		for (t = p; *t != NUL; ++t)
		    if (*t == '\n')
			*t = 'n';
		    else if (*t == '\r')
			*t = 'r';
		if ((fprintf(fd, "let %s = %c%s%c",
				this_var->di_key,
				(this_var->di_tv.v_type == VAR_STRING) ? '"'
									: ' ',
				p,
				(this_var->di_tv.v_type == VAR_STRING) ? '"'
								   : ' ') < 0)
			|| put_eol(fd) == FAIL)
		{
		    vim_free(p);
		    return FAIL;
		}
		vim_free(p);
	    }
#ifdef FEAT_FLOAT
	    else if (this_var->di_tv.v_type == VAR_FLOAT
		    && var_flavour(this_var->di_key) == VAR_FLAVOUR_SESSION)
	    {
		float_T f = this_var->di_tv.vval.v_float;
		int sign = ' ';

		if (f < 0)
		{
		    f = -f;
		    sign = '-';
		}
		if ((fprintf(fd, "let %s = %c%f",
					       this_var->di_key, sign, f) < 0)
			|| put_eol(fd) == FAIL)
		    return FAIL;
	    }
#endif
	}
    }
    return OK;
}
#endif

/*
 * Display script name where an item was last set.
 * Should only be invoked when 'verbose' is non-zero.
 */
    void
last_set_msg(scid_T scriptID)
{
    char_u *p;

    if (scriptID != 0)
    {
	p = home_replace_save(NULL, get_scriptname(scriptID));
	if (p != NULL)
	{
	    verbose_enter();
	    MSG_PUTS(_("\n\tLast set from "));
	    MSG_PUTS(p);
	    vim_free(p);
	    verbose_leave();
	}
    }
}

/* reset v:option_new, v:option_old and v:option_type */
    void
reset_v_option_vars(void)
{
    set_vim_var_string(VV_OPTION_NEW,  NULL, -1);
    set_vim_var_string(VV_OPTION_OLD,  NULL, -1);
    set_vim_var_string(VV_OPTION_TYPE, NULL, -1);
}

/*
 * Prepare "gap" for an assert error and add the sourcing position.
 */
    void
prepare_assert_error(garray_T *gap)
{
    char buf[NUMBUFLEN];

    ga_init2(gap, 1, 100);
    if (sourcing_name != NULL)
    {
	ga_concat(gap, sourcing_name);
	if (sourcing_lnum > 0)
	    ga_concat(gap, (char_u *)" ");
    }
    if (sourcing_lnum > 0)
    {
	sprintf(buf, "line %ld", (long)sourcing_lnum);
	ga_concat(gap, (char_u *)buf);
    }
    if (sourcing_name != NULL || sourcing_lnum > 0)
	ga_concat(gap, (char_u *)": ");
}

/*
 * Add an assert error to v:errors.
 */
    void
assert_error(garray_T *gap)
{
    struct vimvar   *vp = &vimvars[VV_ERRORS];

    if (vp->vv_type != VAR_LIST || vimvars[VV_ERRORS].vv_list == NULL)
	/* Make sure v:errors is a list. */
	set_vim_var_list(VV_ERRORS, list_alloc());
    list_append_string(vimvars[VV_ERRORS].vv_list, gap->ga_data, gap->ga_len);
}

    void
assert_equal_common(typval_T *argvars, assert_type_T atype)
{
    garray_T	ga;

    if (tv_equal(&argvars[0], &argvars[1], FALSE, FALSE)
						   != (atype == ASSERT_EQUAL))
    {
	prepare_assert_error(&ga);
	fill_assert_error(&ga, &argvars[2], NULL, &argvars[0], &argvars[1],
								       atype);
	assert_error(&ga);
	ga_clear(&ga);
    }
}

    void
assert_match_common(typval_T *argvars, assert_type_T atype)
{
    garray_T	ga;
    char_u	buf1[NUMBUFLEN];
    char_u	buf2[NUMBUFLEN];
    char_u	*pat = get_tv_string_buf_chk(&argvars[0], buf1);
    char_u	*text = get_tv_string_buf_chk(&argvars[1], buf2);

    if (pat == NULL || text == NULL)
	EMSG(_(e_invarg));
    else if (pattern_match(pat, text, FALSE) != (atype == ASSERT_MATCH))
    {
	prepare_assert_error(&ga);
	fill_assert_error(&ga, &argvars[2], NULL, &argvars[0], &argvars[1],
									atype);
	assert_error(&ga);
	ga_clear(&ga);
    }
}

    void
assert_inrange(typval_T *argvars)
{
    garray_T	ga;
    int		error = FALSE;
    varnumber_T	lower = get_tv_number_chk(&argvars[0], &error);
    varnumber_T	upper = get_tv_number_chk(&argvars[1], &error);
    varnumber_T	actual = get_tv_number_chk(&argvars[2], &error);
    char_u	*tofree;
    char	msg[200];
    char_u	numbuf[NUMBUFLEN];

    if (error)
	return;
    if (actual < lower || actual > upper)
    {
	prepare_assert_error(&ga);
	if (argvars[3].v_type != VAR_UNKNOWN)
	{
	    ga_concat(&ga, tv2string(&argvars[3], &tofree, numbuf, 0));
	    vim_free(tofree);
	}
	else
	{
	    vim_snprintf(msg, 200, "Expected range %ld - %ld, but got %ld",
				       (long)lower, (long)upper, (long)actual);
	    ga_concat(&ga, (char_u *)msg);
	}
	assert_error(&ga);
	ga_clear(&ga);
    }
}

/*
 * Common for assert_true() and assert_false().
 */
    void
assert_bool(typval_T *argvars, int isTrue)
{
    int		error = FALSE;
    garray_T	ga;

    if (argvars[0].v_type == VAR_SPECIAL
	    && argvars[0].vval.v_number == (isTrue ? VVAL_TRUE : VVAL_FALSE))
	return;
    if (argvars[0].v_type != VAR_NUMBER
	    || (get_tv_number_chk(&argvars[0], &error) == 0) == isTrue
	    || error)
    {
	prepare_assert_error(&ga);
	fill_assert_error(&ga, &argvars[1],
		(char_u *)(isTrue ? "True" : "False"),
		NULL, &argvars[0], ASSERT_OTHER);
	assert_error(&ga);
	ga_clear(&ga);
    }
}

    void
assert_report(typval_T *argvars)
{
    garray_T	ga;

    prepare_assert_error(&ga);
    ga_concat(&ga, get_tv_string(&argvars[0]));
    assert_error(&ga);
    ga_clear(&ga);
}

    void
assert_exception(typval_T *argvars)
{
    garray_T	ga;
    char_u	*error = get_tv_string_chk(&argvars[0]);

    if (vimvars[VV_EXCEPTION].vv_str == NULL)
    {
	prepare_assert_error(&ga);
	ga_concat(&ga, (char_u *)"v:exception is not set");
	assert_error(&ga);
	ga_clear(&ga);
    }
    else if (error != NULL
	&& strstr((char *)vimvars[VV_EXCEPTION].vv_str, (char *)error) == NULL)
    {
	prepare_assert_error(&ga);
	fill_assert_error(&ga, &argvars[1], NULL, &argvars[0],
				  &vimvars[VV_EXCEPTION].vv_tv, ASSERT_OTHER);
	assert_error(&ga);
	ga_clear(&ga);
    }
}

    void
assert_fails(typval_T *argvars)
{
    char_u	*cmd = get_tv_string_chk(&argvars[0]);
    garray_T	ga;

    called_emsg = FALSE;
    suppress_errthrow = TRUE;
    emsg_silent = TRUE;
    do_cmdline_cmd(cmd);
    if (!called_emsg)
    {
	prepare_assert_error(&ga);
	ga_concat(&ga, (char_u *)"command did not fail: ");
	ga_concat(&ga, cmd);
	assert_error(&ga);
	ga_clear(&ga);
    }
    else if (argvars[1].v_type != VAR_UNKNOWN)
    {
	char_u	buf[NUMBUFLEN];
	char	*error = (char *)get_tv_string_buf_chk(&argvars[1], buf);

	if (error == NULL
		  || strstr((char *)vimvars[VV_ERRMSG].vv_str, error) == NULL)
	{
	    prepare_assert_error(&ga);
	    fill_assert_error(&ga, &argvars[2], NULL, &argvars[1],
				     &vimvars[VV_ERRMSG].vv_tv, ASSERT_OTHER);
	    assert_error(&ga);
	    ga_clear(&ga);
	}
    }

    called_emsg = FALSE;
    suppress_errthrow = FALSE;
    emsg_silent = FALSE;
    emsg_on_display = FALSE;
    set_vim_var_string(VV_ERRMSG, NULL, 0);
}

/*
 * Append "str" to "gap", escaping unprintable characters.
 * Changes NL to \n, CR to \r, etc.
 */
    static void
ga_concat_esc(garray_T *gap, char_u *str)
{
    char_u  *p;
    char_u  buf[NUMBUFLEN];

    if (str == NULL)
    {
	ga_concat(gap, (char_u *)"NULL");
	return;
    }

    for (p = str; *p != NUL; ++p)
	switch (*p)
	{
	    case BS: ga_concat(gap, (char_u *)"\\b"); break;
	    case ESC: ga_concat(gap, (char_u *)"\\e"); break;
	    case FF: ga_concat(gap, (char_u *)"\\f"); break;
	    case NL: ga_concat(gap, (char_u *)"\\n"); break;
	    case TAB: ga_concat(gap, (char_u *)"\\t"); break;
	    case CAR: ga_concat(gap, (char_u *)"\\r"); break;
	    case '\\': ga_concat(gap, (char_u *)"\\\\"); break;
	    default:
		if (*p < ' ')
		{
		    vim_snprintf((char *)buf, NUMBUFLEN, "\\x%02x", *p);
		    ga_concat(gap, buf);
		}
		else
		    ga_append(gap, *p);
		break;
	}
}

/*
 * Fill "gap" with information about an assert error.
 */
    void
fill_assert_error(
    garray_T	*gap,
    typval_T	*opt_msg_tv,
    char_u      *exp_str,
    typval_T	*exp_tv,
    typval_T	*got_tv,
    assert_type_T atype)
{
    char_u	numbuf[NUMBUFLEN];
    char_u	*tofree;

    if (opt_msg_tv->v_type != VAR_UNKNOWN)
    {
	ga_concat(gap, echo_string(opt_msg_tv, &tofree, numbuf, 0));
	vim_free(tofree);
	ga_concat(gap, (char_u *)": ");
    }

    if (atype == ASSERT_MATCH || atype == ASSERT_NOTMATCH)
	ga_concat(gap, (char_u *)"Pattern ");
    else if (atype == ASSERT_NOTEQUAL)
	ga_concat(gap, (char_u *)"Expected not equal to ");
    else
	ga_concat(gap, (char_u *)"Expected ");
    if (exp_str == NULL)
    {
	ga_concat_esc(gap, tv2string(exp_tv, &tofree, numbuf, 0));
	vim_free(tofree);
    }
    else
	ga_concat_esc(gap, exp_str);
    if (atype != ASSERT_NOTEQUAL)
    {
	if (atype == ASSERT_MATCH)
	    ga_concat(gap, (char_u *)" does not match ");
	else if (atype == ASSERT_NOTMATCH)
	    ga_concat(gap, (char_u *)" does match ");
	else
	    ga_concat(gap, (char_u *)" but got ");
	ga_concat_esc(gap, tv2string(got_tv, &tofree, numbuf, 0));
	vim_free(tofree);
    }
}


#endif /* FEAT_EVAL */


#if defined(FEAT_MODIFY_FNAME) || defined(FEAT_EVAL) || defined(PROTO)

#ifdef WIN3264
/*
 * Functions for ":8" filename modifier: get 8.3 version of a filename.
 */
static int get_short_pathname(char_u **fnamep, char_u **bufp, int *fnamelen);
static int shortpath_for_invalid_fname(char_u **fname, char_u **bufp, int *fnamelen);
static int shortpath_for_partial(char_u **fnamep, char_u **bufp, int *fnamelen);

/*
 * Get the short path (8.3) for the filename in "fnamep".
 * Only works for a valid file name.
 * When the path gets longer "fnamep" is changed and the allocated buffer
 * is put in "bufp".
 * *fnamelen is the length of "fnamep" and set to 0 for a nonexistent path.
 * Returns OK on success, FAIL on failure.
 */
    static int
get_short_pathname(char_u **fnamep, char_u **bufp, int *fnamelen)
{
    int		l, len;
    char_u	*newbuf;

    len = *fnamelen;
    l = GetShortPathName((LPSTR)*fnamep, (LPSTR)*fnamep, len);
    if (l > len - 1)
    {
	/* If that doesn't work (not enough space), then save the string
	 * and try again with a new buffer big enough. */
	newbuf = vim_strnsave(*fnamep, l);
	if (newbuf == NULL)
	    return FAIL;

	vim_free(*bufp);
	*fnamep = *bufp = newbuf;

	/* Really should always succeed, as the buffer is big enough. */
	l = GetShortPathName((LPSTR)*fnamep, (LPSTR)*fnamep, l+1);
    }

    *fnamelen = l;
    return OK;
}

/*
 * Get the short path (8.3) for the filename in "fname". The converted
 * path is returned in "bufp".
 *
 * Some of the directories specified in "fname" may not exist. This function
 * will shorten the existing directories at the beginning of the path and then
 * append the remaining non-existing path.
 *
 * fname - Pointer to the filename to shorten.  On return, contains the
 *	   pointer to the shortened pathname
 * bufp -  Pointer to an allocated buffer for the filename.
 * fnamelen - Length of the filename pointed to by fname
 *
 * Returns OK on success (or nothing done) and FAIL on failure (out of memory).
 */
    static int
shortpath_for_invalid_fname(
    char_u	**fname,
    char_u	**bufp,
    int		*fnamelen)
{
    char_u	*short_fname, *save_fname, *pbuf_unused;
    char_u	*endp, *save_endp;
    char_u	ch;
    int		old_len, len;
    int		new_len, sfx_len;
    int		retval = OK;

    /* Make a copy */
    old_len = *fnamelen;
    save_fname = vim_strnsave(*fname, old_len);
    pbuf_unused = NULL;
    short_fname = NULL;

    endp = save_fname + old_len - 1; /* Find the end of the copy */
    save_endp = endp;

    /*
     * Try shortening the supplied path till it succeeds by removing one
     * directory at a time from the tail of the path.
     */
    len = 0;
    for (;;)
    {
	/* go back one path-separator */
	while (endp > save_fname && !after_pathsep(save_fname, endp + 1))
	    --endp;
	if (endp <= save_fname)
	    break;		/* processed the complete path */

	/*
	 * Replace the path separator with a NUL and try to shorten the
	 * resulting path.
	 */
	ch = *endp;
	*endp = 0;
	short_fname = save_fname;
	len = (int)STRLEN(short_fname) + 1;
	if (get_short_pathname(&short_fname, &pbuf_unused, &len) == FAIL)
	{
	    retval = FAIL;
	    goto theend;
	}
	*endp = ch;	/* preserve the string */

	if (len > 0)
	    break;	/* successfully shortened the path */

	/* failed to shorten the path. Skip the path separator */
	--endp;
    }

    if (len > 0)
    {
	/*
	 * Succeeded in shortening the path. Now concatenate the shortened
	 * path with the remaining path at the tail.
	 */

	/* Compute the length of the new path. */
	sfx_len = (int)(save_endp - endp) + 1;
	new_len = len + sfx_len;

	*fnamelen = new_len;
	vim_free(*bufp);
	if (new_len > old_len)
	{
	    /* There is not enough space in the currently allocated string,
	     * copy it to a buffer big enough. */
	    *fname = *bufp = vim_strnsave(short_fname, new_len);
	    if (*fname == NULL)
	    {
		retval = FAIL;
		goto theend;
	    }
	}
	else
	{
	    /* Transfer short_fname to the main buffer (it's big enough),
	     * unless get_short_pathname() did its work in-place. */
	    *fname = *bufp = save_fname;
	    if (short_fname != save_fname)
		vim_strncpy(save_fname, short_fname, len);
	    save_fname = NULL;
	}

	/* concat the not-shortened part of the path */
	vim_strncpy(*fname + len, endp, sfx_len);
	(*fname)[new_len] = NUL;
    }

theend:
    vim_free(pbuf_unused);
    vim_free(save_fname);

    return retval;
}

/*
 * Get a pathname for a partial path.
 * Returns OK for success, FAIL for failure.
 */
    static int
shortpath_for_partial(
    char_u	**fnamep,
    char_u	**bufp,
    int		*fnamelen)
{
    int		sepcount, len, tflen;
    char_u	*p;
    char_u	*pbuf, *tfname;
    int		hasTilde;

    /* Count up the path separators from the RHS.. so we know which part
     * of the path to return. */
    sepcount = 0;
    for (p = *fnamep; p < *fnamep + *fnamelen; MB_PTR_ADV(p))
	if (vim_ispathsep(*p))
	    ++sepcount;

    /* Need full path first (use expand_env() to remove a "~/") */
    hasTilde = (**fnamep == '~');
    if (hasTilde)
	pbuf = tfname = expand_env_save(*fnamep);
    else
	pbuf = tfname = FullName_save(*fnamep, FALSE);

    len = tflen = (int)STRLEN(tfname);

    if (get_short_pathname(&tfname, &pbuf, &len) == FAIL)
	return FAIL;

    if (len == 0)
    {
	/* Don't have a valid filename, so shorten the rest of the
	 * path if we can. This CAN give us invalid 8.3 filenames, but
	 * there's not a lot of point in guessing what it might be.
	 */
	len = tflen;
	if (shortpath_for_invalid_fname(&tfname, &pbuf, &len) == FAIL)
	    return FAIL;
    }

    /* Count the paths backward to find the beginning of the desired string. */
    for (p = tfname + len - 1; p >= tfname; --p)
    {
#ifdef FEAT_MBYTE
	if (has_mbyte)
	    p -= mb_head_off(tfname, p);
#endif
	if (vim_ispathsep(*p))
	{
	    if (sepcount == 0 || (hasTilde && sepcount == 1))
		break;
	    else
		sepcount --;
	}
    }
    if (hasTilde)
    {
	--p;
	if (p >= tfname)
	    *p = '~';
	else
	    return FAIL;
    }
    else
	++p;

    /* Copy in the string - p indexes into tfname - allocated at pbuf */
    vim_free(*bufp);
    *fnamelen = (int)STRLEN(p);
    *bufp = pbuf;
    *fnamep = p;

    return OK;
}
#endif /* WIN3264 */

/*
 * Adjust a filename, according to a string of modifiers.
 * *fnamep must be NUL terminated when called.  When returning, the length is
 * determined by *fnamelen.
 * Returns VALID_ flags or -1 for failure.
 * When there is an error, *fnamep is set to NULL.
 */
    int
modify_fname(
    char_u	*src,		/* string with modifiers */
    int		*usedlen,	/* characters after src that are used */
    char_u	**fnamep,	/* file name so far */
    char_u	**bufp,		/* buffer for allocated file name or NULL */
    int		*fnamelen)	/* length of fnamep */
{
    int		valid = 0;
    char_u	*tail;
    char_u	*s, *p, *pbuf;
    char_u	dirname[MAXPATHL];
    int		c;
    int		has_fullname = 0;
#ifdef WIN3264
    char_u	*fname_start = *fnamep;
    int		has_shortname = 0;
#endif

repeat:
    /* ":p" - full path/file_name */
    if (src[*usedlen] == ':' && src[*usedlen + 1] == 'p')
    {
	has_fullname = 1;

	valid |= VALID_PATH;
	*usedlen += 2;

	/* Expand "~/path" for all systems and "~user/path" for Unix and VMS */
	if ((*fnamep)[0] == '~'
#if !defined(UNIX) && !(defined(VMS) && defined(USER_HOME))
		&& ((*fnamep)[1] == '/'
# ifdef BACKSLASH_IN_FILENAME
		    || (*fnamep)[1] == '\\'
# endif
		    || (*fnamep)[1] == NUL)

#endif
	   )
	{
	    *fnamep = expand_env_save(*fnamep);
	    vim_free(*bufp);	/* free any allocated file name */
	    *bufp = *fnamep;
	    if (*fnamep == NULL)
		return -1;
	}

	/* When "/." or "/.." is used: force expansion to get rid of it. */
	for (p = *fnamep; *p != NUL; MB_PTR_ADV(p))
	{
	    if (vim_ispathsep(*p)
		    && p[1] == '.'
		    && (p[2] == NUL
			|| vim_ispathsep(p[2])
			|| (p[2] == '.'
			    && (p[3] == NUL || vim_ispathsep(p[3])))))
		break;
	}

	/* FullName_save() is slow, don't use it when not needed. */
	if (*p != NUL || !vim_isAbsName(*fnamep))
	{
	    *fnamep = FullName_save(*fnamep, *p != NUL);
	    vim_free(*bufp);	/* free any allocated file name */
	    *bufp = *fnamep;
	    if (*fnamep == NULL)
		return -1;
	}

#ifdef WIN3264
# if _WIN32_WINNT >= 0x0500
	if (vim_strchr(*fnamep, '~') != NULL)
	{
	    /* Expand 8.3 filename to full path.  Needed to make sure the same
	     * file does not have two different names.
	     * Note: problem does not occur if _WIN32_WINNT < 0x0500. */
	    p = alloc(_MAX_PATH + 1);
	    if (p != NULL)
	    {
		if (GetLongPathName((LPSTR)*fnamep, (LPSTR)p, _MAX_PATH))
		{
		    vim_free(*bufp);
		    *bufp = *fnamep = p;
		}
		else
		    vim_free(p);
	    }
	}
# endif
#endif
	/* Append a path separator to a directory. */
	if (mch_isdir(*fnamep))
	{
	    /* Make room for one or two extra characters. */
	    *fnamep = vim_strnsave(*fnamep, (int)STRLEN(*fnamep) + 2);
	    vim_free(*bufp);	/* free any allocated file name */
	    *bufp = *fnamep;
	    if (*fnamep == NULL)
		return -1;
	    add_pathsep(*fnamep);
	}
    }

    /* ":." - path relative to the current directory */
    /* ":~" - path relative to the home directory */
    /* ":8" - shortname path - postponed till after */
    while (src[*usedlen] == ':'
		  && ((c = src[*usedlen + 1]) == '.' || c == '~' || c == '8'))
    {
	*usedlen += 2;
	if (c == '8')
	{
#ifdef WIN3264
	    has_shortname = 1; /* Postpone this. */
#endif
	    continue;
	}
	pbuf = NULL;
	/* Need full path first (use expand_env() to remove a "~/") */
	if (!has_fullname)
	{
	    if (c == '.' && **fnamep == '~')
		p = pbuf = expand_env_save(*fnamep);
	    else
		p = pbuf = FullName_save(*fnamep, FALSE);
	}
	else
	    p = *fnamep;

	has_fullname = 0;

	if (p != NULL)
	{
	    if (c == '.')
	    {
		mch_dirname(dirname, MAXPATHL);
		s = shorten_fname(p, dirname);
		if (s != NULL)
		{
		    *fnamep = s;
		    if (pbuf != NULL)
		    {
			vim_free(*bufp);   /* free any allocated file name */
			*bufp = pbuf;
			pbuf = NULL;
		    }
		}
	    }
	    else
	    {
		home_replace(NULL, p, dirname, MAXPATHL, TRUE);
		/* Only replace it when it starts with '~' */
		if (*dirname == '~')
		{
		    s = vim_strsave(dirname);
		    if (s != NULL)
		    {
			*fnamep = s;
			vim_free(*bufp);
			*bufp = s;
		    }
		}
	    }
	    vim_free(pbuf);
	}
    }

    tail = gettail(*fnamep);
    *fnamelen = (int)STRLEN(*fnamep);

    /* ":h" - head, remove "/file_name", can be repeated  */
    /* Don't remove the first "/" or "c:\" */
    while (src[*usedlen] == ':' && src[*usedlen + 1] == 'h')
    {
	valid |= VALID_HEAD;
	*usedlen += 2;
	s = get_past_head(*fnamep);
	while (tail > s && after_pathsep(s, tail))
	    MB_PTR_BACK(*fnamep, tail);
	*fnamelen = (int)(tail - *fnamep);
#ifdef VMS
	if (*fnamelen > 0)
	    *fnamelen += 1; /* the path separator is part of the path */
#endif
	if (*fnamelen == 0)
	{
	    /* Result is empty.  Turn it into "." to make ":cd %:h" work. */
	    p = vim_strsave((char_u *)".");
	    if (p == NULL)
		return -1;
	    vim_free(*bufp);
	    *bufp = *fnamep = tail = p;
	    *fnamelen = 1;
	}
	else
	{
	    while (tail > s && !after_pathsep(s, tail))
		MB_PTR_BACK(*fnamep, tail);
	}
    }

    /* ":8" - shortname  */
    if (src[*usedlen] == ':' && src[*usedlen + 1] == '8')
    {
	*usedlen += 2;
#ifdef WIN3264
	has_shortname = 1;
#endif
    }

#ifdef WIN3264
    /*
     * Handle ":8" after we have done 'heads' and before we do 'tails'.
     */
    if (has_shortname)
    {
	/* Copy the string if it is shortened by :h and when it wasn't copied
	 * yet, because we are going to change it in place.  Avoids changing
	 * the buffer name for "%:8". */
	if (*fnamelen < (int)STRLEN(*fnamep) || *fnamep == fname_start)
	{
	    p = vim_strnsave(*fnamep, *fnamelen);
	    if (p == NULL)
		return -1;
	    vim_free(*bufp);
	    *bufp = *fnamep = p;
	}

	/* Split into two implementations - makes it easier.  First is where
	 * there isn't a full name already, second is where there is. */
	if (!has_fullname && !vim_isAbsName(*fnamep))
	{
	    if (shortpath_for_partial(fnamep, bufp, fnamelen) == FAIL)
		return -1;
	}
	else
	{
	    int		l = *fnamelen;

	    /* Simple case, already have the full-name.
	     * Nearly always shorter, so try first time. */
	    if (get_short_pathname(fnamep, bufp, &l) == FAIL)
		return -1;

	    if (l == 0)
	    {
		/* Couldn't find the filename, search the paths. */
		l = *fnamelen;
		if (shortpath_for_invalid_fname(fnamep, bufp, &l) == FAIL)
		    return -1;
	    }
	    *fnamelen = l;
	}
    }
#endif /* WIN3264 */

    /* ":t" - tail, just the basename */
    if (src[*usedlen] == ':' && src[*usedlen + 1] == 't')
    {
	*usedlen += 2;
	*fnamelen -= (int)(tail - *fnamep);
	*fnamep = tail;
    }

    /* ":e" - extension, can be repeated */
    /* ":r" - root, without extension, can be repeated */
    while (src[*usedlen] == ':'
	    && (src[*usedlen + 1] == 'e' || src[*usedlen + 1] == 'r'))
    {
	/* find a '.' in the tail:
	 * - for second :e: before the current fname
	 * - otherwise: The last '.'
	 */
	if (src[*usedlen + 1] == 'e' && *fnamep > tail)
	    s = *fnamep - 2;
	else
	    s = *fnamep + *fnamelen - 1;
	for ( ; s > tail; --s)
	    if (s[0] == '.')
		break;
	if (src[*usedlen + 1] == 'e')		/* :e */
	{
	    if (s > tail)
	    {
		*fnamelen += (int)(*fnamep - (s + 1));
		*fnamep = s + 1;
#ifdef VMS
		/* cut version from the extension */
		s = *fnamep + *fnamelen - 1;
		for ( ; s > *fnamep; --s)
		    if (s[0] == ';')
			break;
		if (s > *fnamep)
		    *fnamelen = s - *fnamep;
#endif
	    }
	    else if (*fnamep <= tail)
		*fnamelen = 0;
	}
	else				/* :r */
	{
	    if (s > tail)	/* remove one extension */
		*fnamelen = (int)(s - *fnamep);
	}
	*usedlen += 2;
    }

    /* ":s?pat?foo?" - substitute */
    /* ":gs?pat?foo?" - global substitute */
    if (src[*usedlen] == ':'
	    && (src[*usedlen + 1] == 's'
		|| (src[*usedlen + 1] == 'g' && src[*usedlen + 2] == 's')))
    {
	char_u	    *str;
	char_u	    *pat;
	char_u	    *sub;
	int	    sep;
	char_u	    *flags;
	int	    didit = FALSE;

	flags = (char_u *)"";
	s = src + *usedlen + 2;
	if (src[*usedlen + 1] == 'g')
	{
	    flags = (char_u *)"g";
	    ++s;
	}

	sep = *s++;
	if (sep)
	{
	    /* find end of pattern */
	    p = vim_strchr(s, sep);
	    if (p != NULL)
	    {
		pat = vim_strnsave(s, (int)(p - s));
		if (pat != NULL)
		{
		    s = p + 1;
		    /* find end of substitution */
		    p = vim_strchr(s, sep);
		    if (p != NULL)
		    {
			sub = vim_strnsave(s, (int)(p - s));
			str = vim_strnsave(*fnamep, *fnamelen);
			if (sub != NULL && str != NULL)
			{
			    *usedlen = (int)(p + 1 - src);
			    s = do_string_sub(str, pat, sub, NULL, flags);
			    if (s != NULL)
			    {
				*fnamep = s;
				*fnamelen = (int)STRLEN(s);
				vim_free(*bufp);
				*bufp = s;
				didit = TRUE;
			    }
			}
			vim_free(sub);
			vim_free(str);
		    }
		    vim_free(pat);
		}
	    }
	    /* after using ":s", repeat all the modifiers */
	    if (didit)
		goto repeat;
	}
    }

    if (src[*usedlen] == ':' && src[*usedlen + 1] == 'S')
    {
	/* vim_strsave_shellescape() needs a NUL terminated string. */
	c = (*fnamep)[*fnamelen];
	if (c != NUL)
	    (*fnamep)[*fnamelen] = NUL;
	p = vim_strsave_shellescape(*fnamep, FALSE, FALSE);
	if (c != NUL)
	    (*fnamep)[*fnamelen] = c;
	if (p == NULL)
	    return -1;
	vim_free(*bufp);
	*bufp = *fnamep = p;
	*fnamelen = (int)STRLEN(p);
	*usedlen += 2;
    }

    return valid;
}

/*
 * Perform a substitution on "str" with pattern "pat" and substitute "sub".
 * When "sub" is NULL "expr" is used, must be a VAR_FUNC or VAR_PARTIAL.
 * "flags" can be "g" to do a global substitute.
 * Returns an allocated string, NULL for error.
 */
    char_u *
do_string_sub(
    char_u	*str,
    char_u	*pat,
    char_u	*sub,
    typval_T	*expr,
    char_u	*flags)
{
    int		sublen;
    regmatch_T	regmatch;
    int		i;
    int		do_all;
    char_u	*tail;
    char_u	*end;
    garray_T	ga;
    char_u	*ret;
    char_u	*save_cpo;
    char_u	*zero_width = NULL;

    /* Make 'cpoptions' empty, so that the 'l' flag doesn't work here */
    save_cpo = p_cpo;
    p_cpo = empty_option;

    ga_init2(&ga, 1, 200);

    do_all = (flags[0] == 'g');

    regmatch.rm_ic = p_ic;
    regmatch.regprog = vim_regcomp(pat, RE_MAGIC + RE_STRING);
    if (regmatch.regprog != NULL)
    {
	tail = str;
	end = str + STRLEN(str);
	while (vim_regexec_nl(&regmatch, str, (colnr_T)(tail - str)))
	{
	    /* Skip empty match except for first match. */
	    if (regmatch.startp[0] == regmatch.endp[0])
	    {
		if (zero_width == regmatch.startp[0])
		{
		    /* avoid getting stuck on a match with an empty string */
		    i = MB_PTR2LEN(tail);
		    mch_memmove((char_u *)ga.ga_data + ga.ga_len, tail,
								   (size_t)i);
		    ga.ga_len += i;
		    tail += i;
		    continue;
		}
		zero_width = regmatch.startp[0];
	    }

	    /*
	     * Get some space for a temporary buffer to do the substitution
	     * into.  It will contain:
	     * - The text up to where the match is.
	     * - The substituted text.
	     * - The text after the match.
	     */
	    sublen = vim_regsub(&regmatch, sub, expr, tail, FALSE, TRUE, FALSE);
	    if (ga_grow(&ga, (int)((end - tail) + sublen -
			    (regmatch.endp[0] - regmatch.startp[0]))) == FAIL)
	    {
		ga_clear(&ga);
		break;
	    }

	    /* copy the text up to where the match is */
	    i = (int)(regmatch.startp[0] - tail);
	    mch_memmove((char_u *)ga.ga_data + ga.ga_len, tail, (size_t)i);
	    /* add the substituted text */
	    (void)vim_regsub(&regmatch, sub, expr, (char_u *)ga.ga_data
					  + ga.ga_len + i, TRUE, TRUE, FALSE);
	    ga.ga_len += i + sublen - 1;
	    tail = regmatch.endp[0];
	    if (*tail == NUL)
		break;
	    if (!do_all)
		break;
	}

	if (ga.ga_data != NULL)
	    STRCPY((char *)ga.ga_data + ga.ga_len, tail);

	vim_regfree(regmatch.regprog);
    }

    ret = vim_strsave(ga.ga_data == NULL ? str : (char_u *)ga.ga_data);
    ga_clear(&ga);
    if (p_cpo == empty_option)
	p_cpo = save_cpo;
    else
	/* Darn, evaluating {sub} expression or {expr} changed the value. */
	free_string_option(save_cpo);

    return ret;
}

    static int
filter_map_one(typval_T *tv, typval_T *expr, int map, int *remp)
{
    typval_T	rettv;
    typval_T	argv[3];
    char_u	buf[NUMBUFLEN];
    char_u	*s;
    int		retval = FAIL;
    int		dummy;

    copy_tv(tv, &vimvars[VV_VAL].vv_tv);
    argv[0] = vimvars[VV_KEY].vv_tv;
    argv[1] = vimvars[VV_VAL].vv_tv;
    if (expr->v_type == VAR_FUNC)
    {
	s = expr->vval.v_string;
	if (call_func(s, (int)STRLEN(s), &rettv, 2, argv, NULL,
				     0L, 0L, &dummy, TRUE, NULL, NULL) == FAIL)
	    goto theend;
    }
    else if (expr->v_type == VAR_PARTIAL)
    {
	partial_T   *partial = expr->vval.v_partial;

	s = partial_name(partial);
	if (call_func(s, (int)STRLEN(s), &rettv, 2, argv, NULL,
				  0L, 0L, &dummy, TRUE, partial, NULL) == FAIL)
	    goto theend;
    }
    else
    {
	s = get_tv_string_buf_chk(expr, buf);
	if (s == NULL)
	    goto theend;
	s = skipwhite(s);
	if (eval1(&s, &rettv, TRUE) == FAIL)
	    goto theend;
	if (*s != NUL)  /* check for trailing chars after expr */
	{
	    EMSG2(_(e_invexpr2), s);
	    goto theend;
	}
    }
    if (map)
    {
	/* map(): replace the list item value */
	clear_tv(tv);
	rettv.v_lock = 0;
	*tv = rettv;
    }
    else
    {
	int	    error = FALSE;

	/* filter(): when expr is zero remove the item */
	*remp = (get_tv_number_chk(&rettv, &error) == 0);
	clear_tv(&rettv);
	/* On type error, nothing has been removed; return FAIL to stop the
	 * loop.  The error message was given by get_tv_number_chk(). */
	if (error)
	    goto theend;
    }
    retval = OK;
theend:
    clear_tv(&vimvars[VV_VAL].vv_tv);
    return retval;
}


/*
 * Implementation of map() and filter().
 */
    void
filter_map(typval_T *argvars, typval_T *rettv, int map)
{
    typval_T	*expr;
    listitem_T	*li, *nli;
    list_T	*l = NULL;
    dictitem_T	*di;
    hashtab_T	*ht;
    hashitem_T	*hi;
    dict_T	*d = NULL;
    typval_T	save_val;
    typval_T	save_key;
    int		rem;
    int		todo;
    char_u	*ermsg = (char_u *)(map ? "map()" : "filter()");
    char_u	*arg_errmsg = (char_u *)(map ? N_("map() argument")
				   : N_("filter() argument"));
    int		save_did_emsg;
    int		idx = 0;

    if (argvars[0].v_type == VAR_LIST)
    {
	if ((l = argvars[0].vval.v_list) == NULL
	      || (!map && tv_check_lock(l->lv_lock, arg_errmsg, TRUE)))
	    return;
    }
    else if (argvars[0].v_type == VAR_DICT)
    {
	if ((d = argvars[0].vval.v_dict) == NULL
	      || (!map && tv_check_lock(d->dv_lock, arg_errmsg, TRUE)))
	    return;
    }
    else
    {
	EMSG2(_(e_listdictarg), ermsg);
	return;
    }

    expr = &argvars[1];
    /* On type errors, the preceding call has already displayed an error
     * message.  Avoid a misleading error message for an empty string that
     * was not passed as argument. */
    if (expr->v_type != VAR_UNKNOWN)
    {
	prepare_vimvar(VV_VAL, &save_val);

	/* We reset "did_emsg" to be able to detect whether an error
	 * occurred during evaluation of the expression. */
	save_did_emsg = did_emsg;
	did_emsg = FALSE;

	prepare_vimvar(VV_KEY, &save_key);
	if (argvars[0].v_type == VAR_DICT)
	{
	    vimvars[VV_KEY].vv_type = VAR_STRING;

	    ht = &d->dv_hashtab;
	    hash_lock(ht);
	    todo = (int)ht->ht_used;
	    for (hi = ht->ht_array; todo > 0; ++hi)
	    {
		if (!HASHITEM_EMPTY(hi))
		{
		    int r;

		    --todo;
		    di = HI2DI(hi);
		    if (map &&
			    (tv_check_lock(di->di_tv.v_lock, arg_errmsg, TRUE)
			    || var_check_ro(di->di_flags, arg_errmsg, TRUE)))
			break;
		    vimvars[VV_KEY].vv_str = vim_strsave(di->di_key);
		    r = filter_map_one(&di->di_tv, expr, map, &rem);
		    clear_tv(&vimvars[VV_KEY].vv_tv);
		    if (r == FAIL || did_emsg)
			break;
		    if (!map && rem)
		    {
			if (var_check_fixed(di->di_flags, arg_errmsg, TRUE)
			    || var_check_ro(di->di_flags, arg_errmsg, TRUE))
			    break;
			dictitem_remove(d, di);
		    }
		}
	    }
	    hash_unlock(ht);
	}
	else
	{
	    vimvars[VV_KEY].vv_type = VAR_NUMBER;

	    for (li = l->lv_first; li != NULL; li = nli)
	    {
		if (map && tv_check_lock(li->li_tv.v_lock, arg_errmsg, TRUE))
		    break;
		nli = li->li_next;
		vimvars[VV_KEY].vv_nr = idx;
		if (filter_map_one(&li->li_tv, expr, map, &rem) == FAIL
								  || did_emsg)
		    break;
		if (!map && rem)
		    listitem_remove(l, li);
		++idx;
	    }
	}

	restore_vimvar(VV_KEY, &save_key);
	restore_vimvar(VV_VAL, &save_val);

	did_emsg |= save_did_emsg;
    }

    copy_tv(&argvars[0], rettv);
}

#endif /* defined(FEAT_MODIFY_FNAME) || defined(FEAT_EVAL) */