src/cmdexpand.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.
 */

/*
 * cmdexpand.c: functions for command-line completion
 */

#include "vim.h"

static int	cmd_showtail;	// Only show path tail in lists ?

static void	set_expand_context(expand_T *xp);
static int      ExpandGeneric(expand_T *xp, regmatch_T *regmatch,
			      int *num_file, char_u ***file,
			      char_u *((*func)(expand_T *, int)), int escaped);
static int	ExpandFromContext(expand_T *xp, char_u *, int *, char_u ***, int);
static int	expand_showtail(expand_T *xp);
static int	expand_shellcmd(char_u *filepat, int *num_file, char_u ***file, int flagsarg);
#if defined(FEAT_EVAL)
static int	ExpandUserDefined(expand_T *xp, regmatch_T *regmatch, int *num_file, char_u ***file);
static int	ExpandUserList(expand_T *xp, int *num_file, char_u ***file);
#endif

    static int
sort_func_compare(const void *s1, const void *s2)
{
    char_u *p1 = *(char_u **)s1;
    char_u *p2 = *(char_u **)s2;

    if (*p1 != '<' && *p2 == '<') return -1;
    if (*p1 == '<' && *p2 != '<') return 1;
    return STRCMP(p1, p2);
}

    static void
ExpandEscape(
    expand_T	*xp,
    char_u	*str,
    int		numfiles,
    char_u	**files,
    int		options)
{
    int		i;
    char_u	*p;
    int		vse_what = xp->xp_context == EXPAND_BUFFERS
						       ? VSE_BUFFER : VSE_NONE;

    // May change home directory back to "~"
    if (options & WILD_HOME_REPLACE)
	tilde_replace(str, numfiles, files);

    if (options & WILD_ESCAPE)
    {
	if (xp->xp_context == EXPAND_FILES
		|| xp->xp_context == EXPAND_FILES_IN_PATH
		|| xp->xp_context == EXPAND_SHELLCMD
		|| xp->xp_context == EXPAND_BUFFERS
		|| xp->xp_context == EXPAND_DIRECTORIES)
	{
	    // Insert a backslash into a file name before a space, \, %, #
	    // and wildmatch characters, except '~'.
	    for (i = 0; i < numfiles; ++i)
	    {
		// for ":set path=" we need to escape spaces twice
		if (xp->xp_backslash == XP_BS_THREE)
		{
		    p = vim_strsave_escaped(files[i], (char_u *)" ");
		    if (p != NULL)
		    {
			vim_free(files[i]);
			files[i] = p;
#if defined(BACKSLASH_IN_FILENAME)
			p = vim_strsave_escaped(files[i], (char_u *)" ");
			if (p != NULL)
			{
			    vim_free(files[i]);
			    files[i] = p;
			}
#endif
		    }
		}
#ifdef BACKSLASH_IN_FILENAME
		p = vim_strsave_fnameescape(files[i], vse_what);
#else
		p = vim_strsave_fnameescape(files[i],
					  xp->xp_shell ? VSE_SHELL : vse_what);
#endif
		if (p != NULL)
		{
		    vim_free(files[i]);
		    files[i] = p;
		}

		// If 'str' starts with "\~", replace "~" at start of
		// files[i] with "\~".
		if (str[0] == '\\' && str[1] == '~' && files[i][0] == '~')
		    escape_fname(&files[i]);
	    }
	    xp->xp_backslash = XP_BS_NONE;

	    // If the first file starts with a '+' escape it.  Otherwise it
	    // could be seen as "+cmd".
	    if (*files[0] == '+')
		escape_fname(&files[0]);
	}
	else if (xp->xp_context == EXPAND_TAGS)
	{
	    // Insert a backslash before characters in a tag name that
	    // would terminate the ":tag" command.
	    for (i = 0; i < numfiles; ++i)
	    {
		p = vim_strsave_escaped(files[i], (char_u *)"\\|\"");
		if (p != NULL)
		{
		    vim_free(files[i]);
		    files[i] = p;
		}
	    }
	}
    }
}

/*
 * Return FAIL if this is not an appropriate context in which to do
 * completion of anything, return OK if it is (even if there are no matches).
 * For the caller, this means that the character is just passed through like a
 * normal character (instead of being expanded).  This allows :s/^I^D etc.
 */
    int
nextwild(
    expand_T	*xp,
    int		type,
    int		options,	// extra options for ExpandOne()
    int		escape)		// if TRUE, escape the returned matches
{
    cmdline_info_T	*ccline = get_cmdline_info();
    int		i, j;
    char_u	*p1;
    char_u	*p2;
    int		difflen;
    int		v;

    if (xp->xp_numfiles == -1)
    {
	set_expand_context(xp);
	cmd_showtail = expand_showtail(xp);
    }

    if (xp->xp_context == EXPAND_UNSUCCESSFUL)
    {
	beep_flush();
	return OK;  // Something illegal on command line
    }
    if (xp->xp_context == EXPAND_NOTHING)
    {
	// Caller can use the character as a normal char instead
	return FAIL;
    }

    msg_puts("...");	    // show that we are busy
    out_flush();

    i = (int)(xp->xp_pattern - ccline->cmdbuff);
    xp->xp_pattern_len = ccline->cmdpos - i;

    if (type == WILD_NEXT || type == WILD_PREV)
    {
	// Get next/previous match for a previous expanded pattern.
	p2 = ExpandOne(xp, NULL, NULL, 0, type);
    }
    else
    {
	// Translate string into pattern and expand it.
	if ((p1 = addstar(xp->xp_pattern, xp->xp_pattern_len,
						     xp->xp_context)) == NULL)
	    p2 = NULL;
	else
	{
	    int use_options = options |
		    WILD_HOME_REPLACE|WILD_ADD_SLASH|WILD_SILENT;
	    if (escape)
		use_options |= WILD_ESCAPE;

	    if (p_wic)
		use_options += WILD_ICASE;
	    p2 = ExpandOne(xp, p1,
			 vim_strnsave(&ccline->cmdbuff[i], xp->xp_pattern_len),
							   use_options, type);
	    vim_free(p1);
	    // longest match: make sure it is not shorter, happens with :help
	    if (p2 != NULL && type == WILD_LONGEST)
	    {
		for (j = 0; j < xp->xp_pattern_len; ++j)
		     if (ccline->cmdbuff[i + j] == '*'
			     || ccline->cmdbuff[i + j] == '?')
			 break;
		if ((int)STRLEN(p2) < j)
		    VIM_CLEAR(p2);
	    }
	}
    }

    if (p2 != NULL && !got_int)
    {
	difflen = (int)STRLEN(p2) - xp->xp_pattern_len;
	if (ccline->cmdlen + difflen + 4 > ccline->cmdbufflen)
	{
	    v = realloc_cmdbuff(ccline->cmdlen + difflen + 4);
	    xp->xp_pattern = ccline->cmdbuff + i;
	}
	else
	    v = OK;
	if (v == OK)
	{
	    mch_memmove(&ccline->cmdbuff[ccline->cmdpos + difflen],
		    &ccline->cmdbuff[ccline->cmdpos],
		    (size_t)(ccline->cmdlen - ccline->cmdpos + 1));
	    mch_memmove(&ccline->cmdbuff[i], p2, STRLEN(p2));
	    ccline->cmdlen += difflen;
	    ccline->cmdpos += difflen;
	}
    }
    vim_free(p2);

    redrawcmd();
    cursorcmd();

    // When expanding a ":map" command and no matches are found, assume that
    // the key is supposed to be inserted literally
    if (xp->xp_context == EXPAND_MAPPINGS && p2 == NULL)
	return FAIL;

    if (xp->xp_numfiles <= 0 && p2 == NULL)
	beep_flush();
    else if (xp->xp_numfiles == 1)
	// free expanded pattern
	(void)ExpandOne(xp, NULL, NULL, 0, WILD_FREE);

    return OK;
}

/*
 * Do wildcard expansion on the string 'str'.
 * Chars that should not be expanded must be preceded with a backslash.
 * Return a pointer to allocated memory containing the new string.
 * Return NULL for failure.
 *
 * "orig" is the originally expanded string, copied to allocated memory.  It
 * should either be kept in orig_save or freed.  When "mode" is WILD_NEXT or
 * WILD_PREV "orig" should be NULL.
 *
 * Results are cached in xp->xp_files and xp->xp_numfiles, except when "mode"
 * is WILD_EXPAND_FREE or WILD_ALL.
 *
 * mode = WILD_FREE:	    just free previously expanded matches
 * mode = WILD_EXPAND_FREE: normal expansion, do not keep matches
 * mode = WILD_EXPAND_KEEP: normal expansion, keep matches
 * mode = WILD_NEXT:	    use next match in multiple match, wrap to first
 * mode = WILD_PREV:	    use previous match in multiple match, wrap to first
 * mode = WILD_ALL:	    return all matches concatenated
 * mode = WILD_LONGEST:	    return longest matched part
 * mode = WILD_ALL_KEEP:    get all matches, keep matches
 *
 * options = WILD_LIST_NOTFOUND:    list entries without a match
 * options = WILD_HOME_REPLACE:	    do home_replace() for buffer names
 * options = WILD_USE_NL:	    Use '\n' for WILD_ALL
 * options = WILD_NO_BEEP:	    Don't beep for multiple matches
 * options = WILD_ADD_SLASH:	    add a slash after directory names
 * options = WILD_KEEP_ALL:	    don't remove 'wildignore' entries
 * options = WILD_SILENT:	    don't print warning messages
 * options = WILD_ESCAPE:	    put backslash before special chars
 * options = WILD_ICASE:	    ignore case for files
 * options = WILD_ALLLINKS;	    keep broken links
 *
 * The variables xp->xp_context and xp->xp_backslash must have been set!
 */
    char_u *
ExpandOne(
    expand_T	*xp,
    char_u	*str,
    char_u	*orig,	    // allocated copy of original of expanded string
    int		options,
    int		mode)
{
    char_u	*ss = NULL;
    static int	findex;
    static char_u *orig_save = NULL;	// kept value of orig
    int		orig_saved = FALSE;
    int		i;
    long_u	len;
    int		non_suf_match;		// number without matching suffix

    // first handle the case of using an old match
    if (mode == WILD_NEXT || mode == WILD_PREV)
    {
	if (xp->xp_numfiles > 0)
	{
	    if (mode == WILD_PREV)
	    {
		if (findex == -1)
		    findex = xp->xp_numfiles;
		--findex;
	    }
	    else    // mode == WILD_NEXT
		++findex;

	    // When wrapping around, return the original string, set findex to
	    // -1.
	    if (findex < 0)
	    {
		if (orig_save == NULL)
		    findex = xp->xp_numfiles - 1;
		else
		    findex = -1;
	    }
	    if (findex >= xp->xp_numfiles)
	    {
		if (orig_save == NULL)
		    findex = 0;
		else
		    findex = -1;
	    }
#ifdef FEAT_WILDMENU
	    if (p_wmnu)
		win_redr_status_matches(xp, xp->xp_numfiles, xp->xp_files,
							findex, cmd_showtail);
#endif
	    if (findex == -1)
		return vim_strsave(orig_save);
	    return vim_strsave(xp->xp_files[findex]);
	}
	else
	    return NULL;
    }

    // free old names
    if (xp->xp_numfiles != -1 && mode != WILD_ALL && mode != WILD_LONGEST)
    {
	FreeWild(xp->xp_numfiles, xp->xp_files);
	xp->xp_numfiles = -1;
	VIM_CLEAR(orig_save);
    }
    findex = 0;

    if (mode == WILD_FREE)	// only release file name
	return NULL;

    if (xp->xp_numfiles == -1)
    {
	vim_free(orig_save);
	orig_save = orig;
	orig_saved = TRUE;

	// Do the expansion.
	if (ExpandFromContext(xp, str, &xp->xp_numfiles, &xp->xp_files,
							     options) == FAIL)
	{
#ifdef FNAME_ILLEGAL
	    // Illegal file name has been silently skipped.  But when there
	    // are wildcards, the real problem is that there was no match,
	    // causing the pattern to be added, which has illegal characters.
	    if (!(options & WILD_SILENT) && (options & WILD_LIST_NOTFOUND))
		semsg(_(e_nomatch2), str);
#endif
	}
	else if (xp->xp_numfiles == 0)
	{
	    if (!(options & WILD_SILENT))
		semsg(_(e_nomatch2), str);
	}
	else
	{
	    // Escape the matches for use on the command line.
	    ExpandEscape(xp, str, xp->xp_numfiles, xp->xp_files, options);

	    // Check for matching suffixes in file names.
	    if (mode != WILD_ALL && mode != WILD_ALL_KEEP
						      && mode != WILD_LONGEST)
	    {
		if (xp->xp_numfiles)
		    non_suf_match = xp->xp_numfiles;
		else
		    non_suf_match = 1;
		if ((xp->xp_context == EXPAND_FILES
			    || xp->xp_context == EXPAND_DIRECTORIES)
			&& xp->xp_numfiles > 1)
		{
		    // More than one match; check suffix.
		    // The files will have been sorted on matching suffix in
		    // expand_wildcards, only need to check the first two.
		    non_suf_match = 0;
		    for (i = 0; i < 2; ++i)
			if (match_suffix(xp->xp_files[i]))
			    ++non_suf_match;
		}
		if (non_suf_match != 1)
		{
		    // Can we ever get here unless it's while expanding
		    // interactively?  If not, we can get rid of this all
		    // together. Don't really want to wait for this message
		    // (and possibly have to hit return to continue!).
		    if (!(options & WILD_SILENT))
			emsg(_(e_toomany));
		    else if (!(options & WILD_NO_BEEP))
			beep_flush();
		}
		if (!(non_suf_match != 1 && mode == WILD_EXPAND_FREE))
		    ss = vim_strsave(xp->xp_files[0]);
	    }
	}
    }

    // Find longest common part
    if (mode == WILD_LONGEST && xp->xp_numfiles > 0)
    {
	int mb_len = 1;
	int c0, ci;

	for (len = 0; xp->xp_files[0][len]; len += mb_len)
	{
	    if (has_mbyte)
	    {
		mb_len = (*mb_ptr2len)(&xp->xp_files[0][len]);
		c0 =(* mb_ptr2char)(&xp->xp_files[0][len]);
	    }
	    else
		c0 = xp->xp_files[0][len];
	    for (i = 1; i < xp->xp_numfiles; ++i)
	    {
		if (has_mbyte)
		    ci =(* mb_ptr2char)(&xp->xp_files[i][len]);
		else
		    ci = xp->xp_files[i][len];
		if (p_fic && (xp->xp_context == EXPAND_DIRECTORIES
			|| xp->xp_context == EXPAND_FILES
			|| xp->xp_context == EXPAND_SHELLCMD
			|| xp->xp_context == EXPAND_BUFFERS))
		{
		    if (MB_TOLOWER(c0) != MB_TOLOWER(ci))
			break;
		}
		else if (c0 != ci)
		    break;
	    }
	    if (i < xp->xp_numfiles)
	    {
		if (!(options & WILD_NO_BEEP))
		    vim_beep(BO_WILD);
		break;
	    }
	}

	ss = alloc(len + 1);
	if (ss)
	    vim_strncpy(ss, xp->xp_files[0], (size_t)len);
	findex = -1;			    // next p_wc gets first one
    }

    // Concatenate all matching names
    if (mode == WILD_ALL && xp->xp_numfiles > 0)
    {
	len = 0;
	for (i = 0; i < xp->xp_numfiles; ++i)
	    len += (long_u)STRLEN(xp->xp_files[i]) + 1;
	ss = alloc(len);
	if (ss != NULL)
	{
	    *ss = NUL;
	    for (i = 0; i < xp->xp_numfiles; ++i)
	    {
		STRCAT(ss, xp->xp_files[i]);
		if (i != xp->xp_numfiles - 1)
		    STRCAT(ss, (options & WILD_USE_NL) ? "\n" : " ");
	    }
	}
    }

    if (mode == WILD_EXPAND_FREE || mode == WILD_ALL)
	ExpandCleanup(xp);

    // Free "orig" if it wasn't stored in "orig_save".
    if (!orig_saved)
	vim_free(orig);

    return ss;
}

/*
 * Prepare an expand structure for use.
 */
    void
ExpandInit(expand_T *xp)
{
    CLEAR_POINTER(xp);
    xp->xp_backslash = XP_BS_NONE;
    xp->xp_numfiles = -1;
}

/*
 * Cleanup an expand structure after use.
 */
    void
ExpandCleanup(expand_T *xp)
{
    if (xp->xp_numfiles >= 0)
    {
	FreeWild(xp->xp_numfiles, xp->xp_files);
	xp->xp_numfiles = -1;
    }
}

/*
 * Show all matches for completion on the command line.
 * Returns EXPAND_NOTHING when the character that triggered expansion should
 * be inserted like a normal character.
 */
    int
showmatches(expand_T *xp, int wildmenu UNUSED)
{
    cmdline_info_T	*ccline = get_cmdline_info();
#define L_SHOWFILE(m) (showtail ? sm_gettail(files_found[m]) : files_found[m])
    int		num_files;
    char_u	**files_found;
    int		i, j, k;
    int		maxlen;
    int		lines;
    int		columns;
    char_u	*p;
    int		lastlen;
    int		attr;
    int		showtail;

    if (xp->xp_numfiles == -1)
    {
	set_expand_context(xp);
	i = expand_cmdline(xp, ccline->cmdbuff, ccline->cmdpos,
						    &num_files, &files_found);
	showtail = expand_showtail(xp);
	if (i != EXPAND_OK)
	    return i;

    }
    else
    {
	num_files = xp->xp_numfiles;
	files_found = xp->xp_files;
	showtail = cmd_showtail;
    }

#ifdef FEAT_WILDMENU
    if (!wildmenu)
    {
#endif
	msg_didany = FALSE;		// lines_left will be set
	msg_start();			// prepare for paging
	msg_putchar('\n');
	out_flush();
	cmdline_row = msg_row;
	msg_didany = FALSE;		// lines_left will be set again
	msg_start();			// prepare for paging
#ifdef FEAT_WILDMENU
    }
#endif

    if (got_int)
	got_int = FALSE;	// only int. the completion, not the cmd line
#ifdef FEAT_WILDMENU
    else if (wildmenu)
	win_redr_status_matches(xp, num_files, files_found, -1, showtail);
#endif
    else
    {
	// find the length of the longest file name
	maxlen = 0;
	for (i = 0; i < num_files; ++i)
	{
	    if (!showtail && (xp->xp_context == EXPAND_FILES
			  || xp->xp_context == EXPAND_SHELLCMD
			  || xp->xp_context == EXPAND_BUFFERS))
	    {
		home_replace(NULL, files_found[i], NameBuff, MAXPATHL, TRUE);
		j = vim_strsize(NameBuff);
	    }
	    else
		j = vim_strsize(L_SHOWFILE(i));
	    if (j > maxlen)
		maxlen = j;
	}

	if (xp->xp_context == EXPAND_TAGS_LISTFILES)
	    lines = num_files;
	else
	{
	    // compute the number of columns and lines for the listing
	    maxlen += 2;    // two spaces between file names
	    columns = ((int)Columns + 2) / maxlen;
	    if (columns < 1)
		columns = 1;
	    lines = (num_files + columns - 1) / columns;
	}

	attr = HL_ATTR(HLF_D);	// find out highlighting for directories

	if (xp->xp_context == EXPAND_TAGS_LISTFILES)
	{
	    msg_puts_attr(_("tagname"), HL_ATTR(HLF_T));
	    msg_clr_eos();
	    msg_advance(maxlen - 3);
	    msg_puts_attr(_(" kind file\n"), HL_ATTR(HLF_T));
	}

	// list the files line by line
	for (i = 0; i < lines; ++i)
	{
	    lastlen = 999;
	    for (k = i; k < num_files; k += lines)
	    {
		if (xp->xp_context == EXPAND_TAGS_LISTFILES)
		{
		    msg_outtrans_attr(files_found[k], HL_ATTR(HLF_D));
		    p = files_found[k] + STRLEN(files_found[k]) + 1;
		    msg_advance(maxlen + 1);
		    msg_puts((char *)p);
		    msg_advance(maxlen + 3);
		    msg_outtrans_long_attr(p + 2, HL_ATTR(HLF_D));
		    break;
		}
		for (j = maxlen - lastlen; --j >= 0; )
		    msg_putchar(' ');
		if (xp->xp_context == EXPAND_FILES
					  || xp->xp_context == EXPAND_SHELLCMD
					  || xp->xp_context == EXPAND_BUFFERS)
		{
		    // highlight directories
		    if (xp->xp_numfiles != -1)
		    {
			char_u	*halved_slash;
			char_u	*exp_path;
			char_u	*path;

			// Expansion was done before and special characters
			// were escaped, need to halve backslashes.  Also
			// $HOME has been replaced with ~/.
			exp_path = expand_env_save_opt(files_found[k], TRUE);
			path = exp_path != NULL ? exp_path : files_found[k];
			halved_slash = backslash_halve_save(path);
			j = mch_isdir(halved_slash != NULL ? halved_slash
							    : files_found[k]);
			vim_free(exp_path);
			if (halved_slash != path)
			    vim_free(halved_slash);
		    }
		    else
			// Expansion was done here, file names are literal.
			j = mch_isdir(files_found[k]);
		    if (showtail)
			p = L_SHOWFILE(k);
		    else
		    {
			home_replace(NULL, files_found[k], NameBuff, MAXPATHL,
									TRUE);
			p = NameBuff;
		    }
		}
		else
		{
		    j = FALSE;
		    p = L_SHOWFILE(k);
		}
		lastlen = msg_outtrans_attr(p, j ? attr : 0);
	    }
	    if (msg_col > 0)	// when not wrapped around
	    {
		msg_clr_eos();
		msg_putchar('\n');
	    }
	    out_flush();		    // show one line at a time
	    if (got_int)
	    {
		got_int = FALSE;
		break;
	    }
	}

	// we redraw the command below the lines that we have just listed
	// This is a bit tricky, but it saves a lot of screen updating.
	cmdline_row = msg_row;	// will put it back later
    }

    if (xp->xp_numfiles == -1)
	FreeWild(num_files, files_found);

    return EXPAND_OK;
}

/*
 * Private gettail for showmatches() (and win_redr_status_matches()):
 * Find tail of file name path, but ignore trailing "/".
 */
    char_u *
sm_gettail(char_u *s)
{
    char_u	*p;
    char_u	*t = s;
    int		had_sep = FALSE;

    for (p = s; *p != NUL; )
    {
	if (vim_ispathsep(*p)
#ifdef BACKSLASH_IN_FILENAME
		&& !rem_backslash(p)
#endif
	   )
	    had_sep = TRUE;
	else if (had_sep)
	{
	    t = p;
	    had_sep = FALSE;
	}
	MB_PTR_ADV(p);
    }
    return t;
}

/*
 * Return TRUE if we only need to show the tail of completion matches.
 * When not completing file names or there is a wildcard in the path FALSE is
 * returned.
 */
    static int
expand_showtail(expand_T *xp)
{
    char_u	*s;
    char_u	*end;

    // When not completing file names a "/" may mean something different.
    if (xp->xp_context != EXPAND_FILES
	    && xp->xp_context != EXPAND_SHELLCMD
	    && xp->xp_context != EXPAND_DIRECTORIES)
	return FALSE;

    end = gettail(xp->xp_pattern);
    if (end == xp->xp_pattern)		// there is no path separator
	return FALSE;

    for (s = xp->xp_pattern; s < end; s++)
    {
	// Skip escaped wildcards.  Only when the backslash is not a path
	// separator, on DOS the '*' "path\*\file" must not be skipped.
	if (rem_backslash(s))
	    ++s;
	else if (vim_strchr((char_u *)"*?[", *s) != NULL)
	    return FALSE;
    }
    return TRUE;
}

/*
 * Prepare a string for expansion.
 * When expanding file names: The string will be used with expand_wildcards().
 * Copy "fname[len]" into allocated memory and add a '*' at the end.
 * When expanding other names: The string will be used with regcomp().  Copy
 * the name into allocated memory and prepend "^".
 */
    char_u *
addstar(
    char_u	*fname,
    int		len,
    int		context)	// EXPAND_FILES etc.
{
    char_u	*retval;
    int		i, j;
    int		new_len;
    char_u	*tail;
    int		ends_in_star;

    if (context != EXPAND_FILES
	    && context != EXPAND_FILES_IN_PATH
	    && context != EXPAND_SHELLCMD
	    && context != EXPAND_DIRECTORIES)
    {
	// Matching will be done internally (on something other than files).
	// So we convert the file-matching-type wildcards into our kind for
	// use with vim_regcomp().  First work out how long it will be:

	// For help tags the translation is done in find_help_tags().
	// For a tag pattern starting with "/" no translation is needed.
	if (context == EXPAND_HELP
		|| context == EXPAND_COLORS
		|| context == EXPAND_COMPILER
		|| context == EXPAND_OWNSYNTAX
		|| context == EXPAND_FILETYPE
		|| context == EXPAND_PACKADD
		|| ((context == EXPAND_TAGS_LISTFILES
			|| context == EXPAND_TAGS)
		    && fname[0] == '/'))
	    retval = vim_strnsave(fname, len);
	else
	{
	    new_len = len + 2;		// +2 for '^' at start, NUL at end
	    for (i = 0; i < len; i++)
	    {
		if (fname[i] == '*' || fname[i] == '~')
		    new_len++;		// '*' needs to be replaced by ".*"
					// '~' needs to be replaced by "\~"

		// Buffer names are like file names.  "." should be literal
		if (context == EXPAND_BUFFERS && fname[i] == '.')
		    new_len++;		// "." becomes "\."

		// Custom expansion takes care of special things, match
		// backslashes literally (perhaps also for other types?)
		if ((context == EXPAND_USER_DEFINED
			  || context == EXPAND_USER_LIST) && fname[i] == '\\')
		    new_len++;		// '\' becomes "\\"
	    }
	    retval = alloc(new_len);
	    if (retval != NULL)
	    {
		retval[0] = '^';
		j = 1;
		for (i = 0; i < len; i++, j++)
		{
		    // Skip backslash.  But why?  At least keep it for custom
		    // expansion.
		    if (context != EXPAND_USER_DEFINED
			    && context != EXPAND_USER_LIST
			    && fname[i] == '\\'
			    && ++i == len)
			break;

		    switch (fname[i])
		    {
			case '*':   retval[j++] = '.';
				    break;
			case '~':   retval[j++] = '\\';
				    break;
			case '?':   retval[j] = '.';
				    continue;
			case '.':   if (context == EXPAND_BUFFERS)
					retval[j++] = '\\';
				    break;
			case '\\':  if (context == EXPAND_USER_DEFINED
					    || context == EXPAND_USER_LIST)
					retval[j++] = '\\';
				    break;
		    }
		    retval[j] = fname[i];
		}
		retval[j] = NUL;
	    }
	}
    }
    else
    {
	retval = alloc(len + 4);
	if (retval != NULL)
	{
	    vim_strncpy(retval, fname, len);

	    // Don't add a star to *, ~, ~user, $var or `cmd`.
	    // * would become **, which walks the whole tree.
	    // ~ would be at the start of the file name, but not the tail.
	    // $ could be anywhere in the tail.
	    // ` could be anywhere in the file name.
	    // When the name ends in '$' don't add a star, remove the '$'.
	    tail = gettail(retval);
	    ends_in_star = (len > 0 && retval[len - 1] == '*');
#ifndef BACKSLASH_IN_FILENAME
	    for (i = len - 2; i >= 0; --i)
	    {
		if (retval[i] != '\\')
		    break;
		ends_in_star = !ends_in_star;
	    }
#endif
	    if ((*retval != '~' || tail != retval)
		    && !ends_in_star
		    && vim_strchr(tail, '$') == NULL
		    && vim_strchr(retval, '`') == NULL)
		retval[len++] = '*';
	    else if (len > 0 && retval[len - 1] == '$')
		--len;
	    retval[len] = NUL;
	}
    }
    return retval;
}

/*
 * Must parse the command line so far to work out what context we are in.
 * Completion can then be done based on that context.
 * This routine sets the variables:
 *  xp->xp_pattern	    The start of the pattern to be expanded within
 *				the command line (ends at the cursor).
 *  xp->xp_context	    The type of thing to expand.  Will be one of:
 *
 *  EXPAND_UNSUCCESSFUL	    Used sometimes when there is something illegal on
 *			    the command line, like an unknown command.	Caller
 *			    should beep.
 *  EXPAND_NOTHING	    Unrecognised context for completion, use char like
 *			    a normal char, rather than for completion.	eg
 *			    :s/^I/
 *  EXPAND_COMMANDS	    Cursor is still touching the command, so complete
 *			    it.
 *  EXPAND_BUFFERS	    Complete file names for :buf and :sbuf commands.
 *  EXPAND_FILES	    After command with EX_XFILE set, or after setting
 *			    with P_EXPAND set.	eg :e ^I, :w>>^I
 *  EXPAND_DIRECTORIES	    In some cases this is used instead of the latter
 *			    when we know only directories are of interest.  eg
 *			    :set dir=^I
 *  EXPAND_SHELLCMD	    After ":!cmd", ":r !cmd"  or ":w !cmd".
 *  EXPAND_SETTINGS	    Complete variable names.  eg :set d^I
 *  EXPAND_BOOL_SETTINGS    Complete boolean variables only,  eg :set no^I
 *  EXPAND_TAGS		    Complete tags from the files in p_tags.  eg :ta a^I
 *  EXPAND_TAGS_LISTFILES   As above, but list filenames on ^D, after :tselect
 *  EXPAND_HELP		    Complete tags from the file 'helpfile'/tags
 *  EXPAND_EVENTS	    Complete event names
 *  EXPAND_SYNTAX	    Complete :syntax command arguments
 *  EXPAND_HIGHLIGHT	    Complete highlight (syntax) group names
 *  EXPAND_AUGROUP	    Complete autocommand group names
 *  EXPAND_USER_VARS	    Complete user defined variable names, eg :unlet a^I
 *  EXPAND_MAPPINGS	    Complete mapping and abbreviation names,
 *			      eg :unmap a^I , :cunab x^I
 *  EXPAND_FUNCTIONS	    Complete internal or user defined function names,
 *			      eg :call sub^I
 *  EXPAND_USER_FUNC	    Complete user defined function names, eg :delf F^I
 *  EXPAND_EXPRESSION	    Complete internal or user defined function/variable
 *			    names in expressions, eg :while s^I
 *  EXPAND_ENV_VARS	    Complete environment variable names
 *  EXPAND_USER		    Complete user names
 */
    static void
set_expand_context(expand_T *xp)
{
    cmdline_info_T	*ccline = get_cmdline_info();

    // only expansion for ':', '>' and '=' command-lines
    if (ccline->cmdfirstc != ':'
#ifdef FEAT_EVAL
	    && ccline->cmdfirstc != '>' && ccline->cmdfirstc != '='
	    && !ccline->input_fn
#endif
	    )
    {
	xp->xp_context = EXPAND_NOTHING;
	return;
    }
    set_cmd_context(xp, ccline->cmdbuff, ccline->cmdlen, ccline->cmdpos, TRUE);
}

/*
 * This is all pretty much copied from do_one_cmd(), with all the extra stuff
 * we don't need/want deleted.	Maybe this could be done better if we didn't
 * repeat all this stuff.  The only problem is that they may not stay
 * perfectly compatible with each other, but then the command line syntax
 * probably won't change that much -- webb.
 */
    static char_u *
set_one_cmd_context(
    expand_T	*xp,
    char_u	*buff)	    // buffer for command string
{
    char_u		*p;
    char_u		*cmd, *arg;
    int			len = 0;
    exarg_T		ea;
    int			compl = EXPAND_NOTHING;
    int			delim;
    int			forceit = FALSE;
    int			usefilter = FALSE;  // filter instead of file name

    ExpandInit(xp);
    xp->xp_pattern = buff;
    xp->xp_context = EXPAND_COMMANDS;	// Default until we get past command
    ea.argt = 0;

    // 1. skip comment lines and leading space, colons or bars
    for (cmd = buff; vim_strchr((char_u *)" \t:|", *cmd) != NULL; cmd++)
	;
    xp->xp_pattern = cmd;

    if (*cmd == NUL)
	return NULL;
    if (*cmd == '"')	    // ignore comment lines
    {
	xp->xp_context = EXPAND_NOTHING;
	return NULL;
    }

    // 3. Skip over the range to find the command.
    cmd = skip_range(cmd, TRUE, &xp->xp_context);
    xp->xp_pattern = cmd;
    if (*cmd == NUL)
	return NULL;
    if (*cmd == '"')
    {
	xp->xp_context = EXPAND_NOTHING;
	return NULL;
    }

    if (*cmd == '|' || *cmd == '\n')
	return cmd + 1;			// There's another command

    // Isolate the command and search for it in the command table.
    // Exceptions:
    // - the 'k' command can directly be followed by any character, but
    //   do accept "keepmarks", "keepalt" and "keepjumps".
    // - the 's' command can be followed directly by 'c', 'g', 'i', 'I' or 'r'
    if (*cmd == 'k' && cmd[1] != 'e')
    {
	ea.cmdidx = CMD_k;
	p = cmd + 1;
    }
    else
    {
	p = cmd;
	while (ASCII_ISALPHA(*p) || *p == '*')    // Allow * wild card
	    ++p;
	// A user command may contain digits.
	// Include "9" for "vim9*" commands; "vim9cmd" and "vim9script".
	if (ASCII_ISUPPER(cmd[0]) || STRNCMP("vim9", cmd, 4) == 0)
	    while (ASCII_ISALNUM(*p) || *p == '*')
		++p;
	// for python 3.x: ":py3*" commands completion
	if (cmd[0] == 'p' && cmd[1] == 'y' && p == cmd + 2 && *p == '3')
	{
	    ++p;
	    while (ASCII_ISALPHA(*p) || *p == '*')
		++p;
	}
	// check for non-alpha command
	if (p == cmd && vim_strchr((char_u *)"@*!=><&~#", *p) != NULL)
	    ++p;
	len = (int)(p - cmd);

	if (len == 0)
	{
	    xp->xp_context = EXPAND_UNSUCCESSFUL;
	    return NULL;
	}

	ea.cmdidx = excmd_get_cmdidx(cmd, len);

	if (cmd[0] >= 'A' && cmd[0] <= 'Z')
	    while (ASCII_ISALNUM(*p) || *p == '*')	// Allow * wild card
		++p;
    }

    // If the cursor is touching the command, and it ends in an alphanumeric
    // character, complete the command name.
    if (*p == NUL && ASCII_ISALNUM(p[-1]))
	return NULL;

    if (ea.cmdidx == CMD_SIZE)
    {
	if (*cmd == 's' && vim_strchr((char_u *)"cgriI", cmd[1]) != NULL)
	{
	    ea.cmdidx = CMD_substitute;
	    p = cmd + 1;
	}
	else if (cmd[0] >= 'A' && cmd[0] <= 'Z')
	{
	    ea.cmd = cmd;
	    p = find_ucmd(&ea, p, NULL, xp, &compl);
	    if (p == NULL)
		ea.cmdidx = CMD_SIZE;	// ambiguous user command
	}
    }
    if (ea.cmdidx == CMD_SIZE)
    {
	// Not still touching the command and it was an illegal one
	xp->xp_context = EXPAND_UNSUCCESSFUL;
	return NULL;
    }

    xp->xp_context = EXPAND_NOTHING; // Default now that we're past command

    if (*p == '!')		    // forced commands
    {
	forceit = TRUE;
	++p;
    }

    // 6. parse arguments
    if (!IS_USER_CMDIDX(ea.cmdidx))
	ea.argt = excmd_get_argt(ea.cmdidx);

    arg = skipwhite(p);

    // Skip over ++argopt argument
    if ((ea.argt & EX_ARGOPT) && *arg != NUL && STRNCMP(arg, "++", 2) == 0)
    {
	p = arg;
	while (*p && !vim_isspace(*p))
	    MB_PTR_ADV(p);
	arg = skipwhite(p);
    }

    if (ea.cmdidx == CMD_write || ea.cmdidx == CMD_update)
    {
	if (*arg == '>')			// append
	{
	    if (*++arg == '>')
		++arg;
	    arg = skipwhite(arg);
	}
	else if (*arg == '!' && ea.cmdidx == CMD_write)	// :w !filter
	{
	    ++arg;
	    usefilter = TRUE;
	}
    }

    if (ea.cmdidx == CMD_read)
    {
	usefilter = forceit;			// :r! filter if forced
	if (*arg == '!')			// :r !filter
	{
	    ++arg;
	    usefilter = TRUE;
	}
    }

    if (ea.cmdidx == CMD_lshift || ea.cmdidx == CMD_rshift)
    {
	while (*arg == *cmd)	    // allow any number of '>' or '<'
	    ++arg;
	arg = skipwhite(arg);
    }

    // Does command allow "+command"?
    if ((ea.argt & EX_CMDARG) && !usefilter && *arg == '+')
    {
	// Check if we're in the +command
	p = arg + 1;
	arg = skip_cmd_arg(arg, FALSE);

	// Still touching the command after '+'?
	if (*arg == NUL)
	    return p;

	// Skip space(s) after +command to get to the real argument
	arg = skipwhite(arg);
    }


    // Check for '|' to separate commands and '"' to start comments.
    // Don't do this for ":read !cmd" and ":write !cmd".
    if ((ea.argt & EX_TRLBAR) && !usefilter)
    {
	p = arg;
	// ":redir @" is not the start of a comment
	if (ea.cmdidx == CMD_redir && p[0] == '@' && p[1] == '"')
	    p += 2;
	while (*p)
	{
	    if (*p == Ctrl_V)
	    {
		if (p[1] != NUL)
		    ++p;
	    }
	    else if ( (*p == '"' && !(ea.argt & EX_NOTRLCOM))
		    || *p == '|' || *p == '\n')
	    {
		if (*(p - 1) != '\\')
		{
		    if (*p == '|' || *p == '\n')
			return p + 1;
		    return NULL;    // It's a comment
		}
	    }
	    MB_PTR_ADV(p);
	}
    }

    if (!(ea.argt & EX_EXTRA) && *arg != NUL
				  && vim_strchr((char_u *)"|\"", *arg) == NULL)
	// no arguments allowed but there is something
	return NULL;

    // Find start of last argument (argument just before cursor):
    p = buff;
    xp->xp_pattern = p;
    len = (int)STRLEN(buff);
    while (*p && p < buff + len)
    {
	if (*p == ' ' || *p == TAB)
	{
	    // argument starts after a space
	    xp->xp_pattern = ++p;
	}
	else
	{
	    if (*p == '\\' && *(p + 1) != NUL)
		++p; // skip over escaped character
	    MB_PTR_ADV(p);
	}
    }

    if (ea.argt & EX_XFILE)
    {
	int	c;
	int	in_quote = FALSE;
	char_u	*bow = NULL;	// Beginning of word

	// Allow spaces within back-quotes to count as part of the argument
	// being expanded.
	xp->xp_pattern = skipwhite(arg);
	p = xp->xp_pattern;
	while (*p != NUL)
	{
	    if (has_mbyte)
		c = mb_ptr2char(p);
	    else
		c = *p;
	    if (c == '\\' && p[1] != NUL)
		++p;
	    else if (c == '`')
	    {
		if (!in_quote)
		{
		    xp->xp_pattern = p;
		    bow = p + 1;
		}
		in_quote = !in_quote;
	    }
	    // An argument can contain just about everything, except
	    // characters that end the command and white space.
	    else if (c == '|' || c == '\n' || c == '"' || (VIM_ISWHITE(c)
#ifdef SPACE_IN_FILENAME
					&& (!(ea.argt & EX_NOSPC) || usefilter)
#endif
		    ))
	    {
		len = 0;  // avoid getting stuck when space is in 'isfname'
		while (*p != NUL)
		{
		    if (has_mbyte)
			c = mb_ptr2char(p);
		    else
			c = *p;
		    if (c == '`' || vim_isfilec_or_wc(c))
			break;
		    if (has_mbyte)
			len = (*mb_ptr2len)(p);
		    else
			len = 1;
		    MB_PTR_ADV(p);
		}
		if (in_quote)
		    bow = p;
		else
		    xp->xp_pattern = p;
		p -= len;
	    }
	    MB_PTR_ADV(p);
	}

	// If we are still inside the quotes, and we passed a space, just
	// expand from there.
	if (bow != NULL && in_quote)
	    xp->xp_pattern = bow;
	xp->xp_context = EXPAND_FILES;

	// For a shell command more chars need to be escaped.
	if (usefilter || ea.cmdidx == CMD_bang || ea.cmdidx == CMD_terminal)
	{
#ifndef BACKSLASH_IN_FILENAME
	    xp->xp_shell = TRUE;
#endif
	    // When still after the command name expand executables.
	    if (xp->xp_pattern == skipwhite(arg))
		xp->xp_context = EXPAND_SHELLCMD;
	}

	// Check for environment variable.
	if (*xp->xp_pattern == '$')
	{
	    for (p = xp->xp_pattern + 1; *p != NUL; ++p)
		if (!vim_isIDc(*p))
		    break;
	    if (*p == NUL)
	    {
		xp->xp_context = EXPAND_ENV_VARS;
		++xp->xp_pattern;
		// Avoid that the assignment uses EXPAND_FILES again.
		if (compl != EXPAND_USER_DEFINED && compl != EXPAND_USER_LIST)
		    compl = EXPAND_ENV_VARS;
	    }
	}
	// Check for user names.
	if (*xp->xp_pattern == '~')
	{
	    for (p = xp->xp_pattern + 1; *p != NUL && *p != '/'; ++p)
		;
	    // Complete ~user only if it partially matches a user name.
	    // A full match ~user<Tab> will be replaced by user's home
	    // directory i.e. something like ~user<Tab> -> /home/user/
	    if (*p == NUL && p > xp->xp_pattern + 1
				       && match_user(xp->xp_pattern + 1) >= 1)
	    {
		xp->xp_context = EXPAND_USER;
		++xp->xp_pattern;
	    }
	}
    }

    // 6. Switch on command name.
    switch (ea.cmdidx)
    {
	case CMD_find:
	case CMD_sfind:
	case CMD_tabfind:
	    if (xp->xp_context == EXPAND_FILES)
		xp->xp_context = EXPAND_FILES_IN_PATH;
	    break;
	case CMD_cd:
	case CMD_chdir:
	case CMD_tcd:
	case CMD_tchdir:
	case CMD_lcd:
	case CMD_lchdir:
	    if (xp->xp_context == EXPAND_FILES)
		xp->xp_context = EXPAND_DIRECTORIES;
	    break;
	case CMD_help:
	    xp->xp_context = EXPAND_HELP;
	    xp->xp_pattern = arg;
	    break;

	// Command modifiers: return the argument.
	// Also for commands with an argument that is a command.
	case CMD_aboveleft:
	case CMD_argdo:
	case CMD_belowright:
	case CMD_botright:
	case CMD_browse:
	case CMD_bufdo:
	case CMD_cdo:
	case CMD_cfdo:
	case CMD_confirm:
	case CMD_debug:
	case CMD_folddoclosed:
	case CMD_folddoopen:
	case CMD_hide:
	case CMD_keepalt:
	case CMD_keepjumps:
	case CMD_keepmarks:
	case CMD_keeppatterns:
	case CMD_ldo:
	case CMD_leftabove:
	case CMD_lfdo:
	case CMD_lockmarks:
	case CMD_noautocmd:
	case CMD_noswapfile:
	case CMD_rightbelow:
	case CMD_sandbox:
	case CMD_silent:
	case CMD_tab:
	case CMD_tabdo:
	case CMD_topleft:
	case CMD_verbose:
	case CMD_vertical:
	case CMD_windo:
	case CMD_vim9cmd:
	case CMD_legacy:
	    return arg;

	case CMD_filter:
	    if (*arg != NUL)
		arg = skip_vimgrep_pat(arg, NULL, NULL);
	    if (arg == NULL || *arg == NUL)
	    {
		xp->xp_context = EXPAND_NOTHING;
		return NULL;
	    }
	    return skipwhite(arg);

#ifdef FEAT_SEARCH_EXTRA
	case CMD_match:
	    if (*arg == NUL || !ends_excmd(*arg))
	    {
		// also complete "None"
		set_context_in_echohl_cmd(xp, arg);
		arg = skipwhite(skiptowhite(arg));
		if (*arg != NUL)
		{
		    xp->xp_context = EXPAND_NOTHING;
		    arg = skip_regexp(arg + 1, *arg, magic_isset());
		}
	    }
	    return find_nextcmd(arg);
#endif

	// All completion for the +cmdline_compl feature goes here.

	case CMD_command:
	    return set_context_in_user_cmd(xp, arg);

	case CMD_delcommand:
	    xp->xp_context = EXPAND_USER_COMMANDS;
	    xp->xp_pattern = arg;
	    break;

	case CMD_global:
	case CMD_vglobal:
	    delim = *arg;	    // get the delimiter
	    if (delim)
		++arg;		    // skip delimiter if there is one

	    while (arg[0] != NUL && arg[0] != delim)
	    {
		if (arg[0] == '\\' && arg[1] != NUL)
		    ++arg;
		++arg;
	    }
	    if (arg[0] != NUL)
		return arg + 1;
	    break;
	case CMD_and:
	case CMD_substitute:
	    delim = *arg;
	    if (delim)
	    {
		// skip "from" part
		++arg;
		arg = skip_regexp(arg, delim, magic_isset());
	    }
	    // skip "to" part
	    while (arg[0] != NUL && arg[0] != delim)
	    {
		if (arg[0] == '\\' && arg[1] != NUL)
		    ++arg;
		++arg;
	    }
	    if (arg[0] != NUL)	// skip delimiter
		++arg;
	    while (arg[0] && vim_strchr((char_u *)"|\"#", arg[0]) == NULL)
		++arg;
	    if (arg[0] != NUL)
		return arg;
	    break;
	case CMD_isearch:
	case CMD_dsearch:
	case CMD_ilist:
	case CMD_dlist:
	case CMD_ijump:
	case CMD_psearch:
	case CMD_djump:
	case CMD_isplit:
	case CMD_dsplit:
	    arg = skipwhite(skipdigits(arg));	    // skip count
	    if (*arg == '/')	// Match regexp, not just whole words
	    {
		for (++arg; *arg && *arg != '/'; arg++)
		    if (*arg == '\\' && arg[1] != NUL)
			arg++;
		if (*arg)
		{
		    arg = skipwhite(arg + 1);

		    // Check for trailing illegal characters
		    if (*arg && vim_strchr((char_u *)"|\"\n", *arg) == NULL)
			xp->xp_context = EXPAND_NOTHING;
		    else
			return arg;
		}
	    }
	    break;

	case CMD_autocmd:
	    return set_context_in_autocmd(xp, arg, FALSE);
	case CMD_doautocmd:
	case CMD_doautoall:
	    return set_context_in_autocmd(xp, arg, TRUE);
	case CMD_set:
	    set_context_in_set_cmd(xp, arg, 0);
	    break;
	case CMD_setglobal:
	    set_context_in_set_cmd(xp, arg, OPT_GLOBAL);
	    break;
	case CMD_setlocal:
	    set_context_in_set_cmd(xp, arg, OPT_LOCAL);
	    break;
	case CMD_tag:
	case CMD_stag:
	case CMD_ptag:
	case CMD_ltag:
	case CMD_tselect:
	case CMD_stselect:
	case CMD_ptselect:
	case CMD_tjump:
	case CMD_stjump:
	case CMD_ptjump:
	    if (*p_wop != NUL)
		xp->xp_context = EXPAND_TAGS_LISTFILES;
	    else
		xp->xp_context = EXPAND_TAGS;
	    xp->xp_pattern = arg;
	    break;
	case CMD_augroup:
	    xp->xp_context = EXPAND_AUGROUP;
	    xp->xp_pattern = arg;
	    break;
#ifdef FEAT_SYN_HL
	case CMD_syntax:
	    set_context_in_syntax_cmd(xp, arg);
	    break;
#endif
#ifdef FEAT_EVAL
	case CMD_final:
	case CMD_const:
	case CMD_let:
	case CMD_var:
	case CMD_if:
	case CMD_elseif:
	case CMD_while:
	case CMD_for:
	case CMD_echo:
	case CMD_echon:
	case CMD_execute:
	case CMD_echomsg:
	case CMD_echoerr:
	case CMD_call:
	case CMD_return:
	case CMD_cexpr:
	case CMD_caddexpr:
	case CMD_cgetexpr:
	case CMD_lexpr:
	case CMD_laddexpr:
	case CMD_lgetexpr:
	    set_context_for_expression(xp, arg, ea.cmdidx);
	    break;

	case CMD_unlet:
	    while ((xp->xp_pattern = vim_strchr(arg, ' ')) != NULL)
		arg = xp->xp_pattern + 1;

	    xp->xp_context = EXPAND_USER_VARS;
	    xp->xp_pattern = arg;

	    if (*xp->xp_pattern == '$')
	    {
		xp->xp_context = EXPAND_ENV_VARS;
		++xp->xp_pattern;
	    }

	    break;

	case CMD_function:
	case CMD_delfunction:
	    xp->xp_context = EXPAND_USER_FUNC;
	    xp->xp_pattern = arg;
	    break;
	case CMD_disassemble:
	    set_context_in_disassemble_cmd(xp, arg);
	    break;

	case CMD_echohl:
	    set_context_in_echohl_cmd(xp, arg);
	    break;
#endif
	case CMD_highlight:
	    set_context_in_highlight_cmd(xp, arg);
	    break;
#ifdef FEAT_CSCOPE
	case CMD_cscope:
	case CMD_lcscope:
	case CMD_scscope:
	    set_context_in_cscope_cmd(xp, arg, ea.cmdidx);
	    break;
#endif
#ifdef FEAT_SIGNS
	case CMD_sign:
	    set_context_in_sign_cmd(xp, arg);
	    break;
#endif
	case CMD_bdelete:
	case CMD_bwipeout:
	case CMD_bunload:
	    while ((xp->xp_pattern = vim_strchr(arg, ' ')) != NULL)
		arg = xp->xp_pattern + 1;
	    // FALLTHROUGH
	case CMD_buffer:
	case CMD_sbuffer:
	case CMD_checktime:
	    xp->xp_context = EXPAND_BUFFERS;
	    xp->xp_pattern = arg;
	    break;
#ifdef FEAT_DIFF
	case CMD_diffget:
	case CMD_diffput:
	    // If current buffer is in diff mode, complete buffer names
	    // which are in diff mode, and different than current buffer.
	    xp->xp_context = EXPAND_DIFF_BUFFERS;
	    xp->xp_pattern = arg;
	    break;
#endif
	case CMD_USER:
	case CMD_USER_BUF:
	    if (compl != EXPAND_NOTHING)
	    {
		// EX_XFILE: file names are handled above
		if (!(ea.argt & EX_XFILE))
		{
#ifdef FEAT_MENU
		    if (compl == EXPAND_MENUS)
			return set_context_in_menu_cmd(xp, cmd, arg, forceit);
#endif
		    if (compl == EXPAND_COMMANDS)
			return arg;
		    if (compl == EXPAND_MAPPINGS)
			return set_context_in_map_cmd(xp, (char_u *)"map",
					 arg, forceit, FALSE, FALSE, CMD_map);
		    // Find start of last argument.
		    p = arg;
		    while (*p)
		    {
			if (*p == ' ')
			    // argument starts after a space
			    arg = p + 1;
			else if (*p == '\\' && *(p + 1) != NUL)
			    ++p; // skip over escaped character
			MB_PTR_ADV(p);
		    }
		    xp->xp_pattern = arg;
		}
		xp->xp_context = compl;
	    }
	    break;

	case CMD_map:	    case CMD_noremap:
	case CMD_nmap:	    case CMD_nnoremap:
	case CMD_vmap:	    case CMD_vnoremap:
	case CMD_omap:	    case CMD_onoremap:
	case CMD_imap:	    case CMD_inoremap:
	case CMD_cmap:	    case CMD_cnoremap:
	case CMD_lmap:	    case CMD_lnoremap:
	case CMD_smap:	    case CMD_snoremap:
	case CMD_tmap:	    case CMD_tnoremap:
	case CMD_xmap:	    case CMD_xnoremap:
	    return set_context_in_map_cmd(xp, cmd, arg, forceit,
						     FALSE, FALSE, ea.cmdidx);
	case CMD_unmap:
	case CMD_nunmap:
	case CMD_vunmap:
	case CMD_ounmap:
	case CMD_iunmap:
	case CMD_cunmap:
	case CMD_lunmap:
	case CMD_sunmap:
	case CMD_tunmap:
	case CMD_xunmap:
	    return set_context_in_map_cmd(xp, cmd, arg, forceit,
						      FALSE, TRUE, ea.cmdidx);
	case CMD_mapclear:
	case CMD_nmapclear:
	case CMD_vmapclear:
	case CMD_omapclear:
	case CMD_imapclear:
	case CMD_cmapclear:
	case CMD_lmapclear:
	case CMD_smapclear:
	case CMD_tmapclear:
	case CMD_xmapclear:
	    xp->xp_context = EXPAND_MAPCLEAR;
	    xp->xp_pattern = arg;
	    break;

	case CMD_abbreviate:	case CMD_noreabbrev:
	case CMD_cabbrev:	case CMD_cnoreabbrev:
	case CMD_iabbrev:	case CMD_inoreabbrev:
	    return set_context_in_map_cmd(xp, cmd, arg, forceit,
						      TRUE, FALSE, ea.cmdidx);
	case CMD_unabbreviate:
	case CMD_cunabbrev:
	case CMD_iunabbrev:
	    return set_context_in_map_cmd(xp, cmd, arg, forceit,
						       TRUE, TRUE, ea.cmdidx);
#ifdef FEAT_MENU
	case CMD_menu:	    case CMD_noremenu:	    case CMD_unmenu:
	case CMD_amenu:	    case CMD_anoremenu:	    case CMD_aunmenu:
	case CMD_nmenu:	    case CMD_nnoremenu:	    case CMD_nunmenu:
	case CMD_vmenu:	    case CMD_vnoremenu:	    case CMD_vunmenu:
	case CMD_omenu:	    case CMD_onoremenu:	    case CMD_ounmenu:
	case CMD_imenu:	    case CMD_inoremenu:	    case CMD_iunmenu:
	case CMD_cmenu:	    case CMD_cnoremenu:	    case CMD_cunmenu:
	case CMD_tlmenu:    case CMD_tlnoremenu:    case CMD_tlunmenu:
	case CMD_tmenu:				    case CMD_tunmenu:
	case CMD_popup:	    case CMD_tearoff:	    case CMD_emenu:
	    return set_context_in_menu_cmd(xp, cmd, arg, forceit);
#endif

	case CMD_colorscheme:
	    xp->xp_context = EXPAND_COLORS;
	    xp->xp_pattern = arg;
	    break;

	case CMD_compiler:
	    xp->xp_context = EXPAND_COMPILER;
	    xp->xp_pattern = arg;
	    break;

	case CMD_ownsyntax:
	    xp->xp_context = EXPAND_OWNSYNTAX;
	    xp->xp_pattern = arg;
	    break;

	case CMD_setfiletype:
	    xp->xp_context = EXPAND_FILETYPE;
	    xp->xp_pattern = arg;
	    break;

	case CMD_packadd:
	    xp->xp_context = EXPAND_PACKADD;
	    xp->xp_pattern = arg;
	    break;

#if defined(HAVE_LOCALE_H) || defined(X_LOCALE)
	case CMD_language:
	    p = skiptowhite(arg);
	    if (*p == NUL)
	    {
		xp->xp_context = EXPAND_LANGUAGE;
		xp->xp_pattern = arg;
	    }
	    else
	    {
		if ( STRNCMP(arg, "messages", p - arg) == 0
		  || STRNCMP(arg, "ctype", p - arg) == 0
		  || STRNCMP(arg, "time", p - arg) == 0
		  || STRNCMP(arg, "collate", p - arg) == 0)
		{
		    xp->xp_context = EXPAND_LOCALES;
		    xp->xp_pattern = skipwhite(p);
		}
		else
		    xp->xp_context = EXPAND_NOTHING;
	    }
	    break;
#endif
#if defined(FEAT_PROFILE)
	case CMD_profile:
	    set_context_in_profile_cmd(xp, arg);
	    break;
#endif
	case CMD_behave:
	    xp->xp_context = EXPAND_BEHAVE;
	    xp->xp_pattern = arg;
	    break;

	case CMD_messages:
	    xp->xp_context = EXPAND_MESSAGES;
	    xp->xp_pattern = arg;
	    break;

	case CMD_history:
	    xp->xp_context = EXPAND_HISTORY;
	    xp->xp_pattern = arg;
	    break;
#if defined(FEAT_PROFILE)
	case CMD_syntime:
	    xp->xp_context = EXPAND_SYNTIME;
	    xp->xp_pattern = arg;
	    break;
#endif

	case CMD_argdelete:
	    while ((xp->xp_pattern = vim_strchr(arg, ' ')) != NULL)
		arg = xp->xp_pattern + 1;
	    xp->xp_context = EXPAND_ARGLIST;
	    xp->xp_pattern = arg;
	    break;

	default:
	    break;
    }
    return NULL;
}

    void
set_cmd_context(
    expand_T	*xp,
    char_u	*str,	    // start of command line
    int		len,	    // length of command line (excl. NUL)
    int		col,	    // position of cursor
    int		use_ccline UNUSED) // use ccline for info
{
#ifdef FEAT_EVAL
    cmdline_info_T	*ccline = get_cmdline_info();
#endif
    int		old_char = NUL;
    char_u	*nextcomm;

    // Avoid a UMR warning from Purify, only save the character if it has been
    // written before.
    if (col < len)
	old_char = str[col];
    str[col] = NUL;
    nextcomm = str;

#ifdef FEAT_EVAL
    if (use_ccline && ccline->cmdfirstc == '=')
    {
	// pass CMD_SIZE because there is no real command
	set_context_for_expression(xp, str, CMD_SIZE);
    }
    else if (use_ccline && ccline->input_fn)
    {
	xp->xp_context = ccline->xp_context;
	xp->xp_pattern = ccline->cmdbuff;
	xp->xp_arg = ccline->xp_arg;
    }
    else
#endif
	while (nextcomm != NULL)
	    nextcomm = set_one_cmd_context(xp, nextcomm);

    // Store the string here so that call_user_expand_func() can get to them
    // easily.
    xp->xp_line = str;
    xp->xp_col = col;

    str[col] = old_char;
}

/*
 * Expand the command line "str" from context "xp".
 * "xp" must have been set by set_cmd_context().
 * xp->xp_pattern points into "str", to where the text that is to be expanded
 * starts.
 * Returns EXPAND_UNSUCCESSFUL when there is something illegal before the
 * cursor.
 * Returns EXPAND_NOTHING when there is nothing to expand, might insert the
 * key that triggered expansion literally.
 * Returns EXPAND_OK otherwise.
 */
    int
expand_cmdline(
    expand_T	*xp,
    char_u	*str,		// start of command line
    int		col,		// position of cursor
    int		*matchcount,	// return: nr of matches
    char_u	***matches)	// return: array of pointers to matches
{
    char_u	*file_str = NULL;
    int		options = WILD_ADD_SLASH|WILD_SILENT;

    if (xp->xp_context == EXPAND_UNSUCCESSFUL)
    {
	beep_flush();
	return EXPAND_UNSUCCESSFUL;  // Something illegal on command line
    }
    if (xp->xp_context == EXPAND_NOTHING)
    {
	// Caller can use the character as a normal char instead
	return EXPAND_NOTHING;
    }

    // add star to file name, or convert to regexp if not exp. files.
    xp->xp_pattern_len = (int)(str + col - xp->xp_pattern);
    file_str = addstar(xp->xp_pattern, xp->xp_pattern_len, xp->xp_context);
    if (file_str == NULL)
	return EXPAND_UNSUCCESSFUL;

    if (p_wic)
	options += WILD_ICASE;

    // find all files that match the description
    if (ExpandFromContext(xp, file_str, matchcount, matches, options) == FAIL)
    {
	*matchcount = 0;
	*matches = NULL;
    }
    vim_free(file_str);

    return EXPAND_OK;
}

/*
 * Function given to ExpandGeneric() to obtain the possible arguments of the
 * ":behave {mswin,xterm}" command.
 */
    static char_u *
get_behave_arg(expand_T *xp UNUSED, int idx)
{
    if (idx == 0)
	return (char_u *)"mswin";
    if (idx == 1)
	return (char_u *)"xterm";
    return NULL;
}

/*
 * Function given to ExpandGeneric() to obtain the possible arguments of the
 * ":messages {clear}" command.
 */
    static char_u *
get_messages_arg(expand_T *xp UNUSED, int idx)
{
    if (idx == 0)
	return (char_u *)"clear";
    return NULL;
}

    static char_u *
get_mapclear_arg(expand_T *xp UNUSED, int idx)
{
    if (idx == 0)
	return (char_u *)"<buffer>";
    return NULL;
}

/*
 * Do the expansion based on xp->xp_context and "pat".
 */
    static int
ExpandFromContext(
    expand_T	*xp,
    char_u	*pat,
    int		*num_file,
    char_u	***file,
    int		options)  // WILD_ flags
{
    regmatch_T	regmatch;
    int		ret;
    int		flags;
    char_u	*tofree = NULL;

    flags = EW_DIR;	// include directories
    if (options & WILD_LIST_NOTFOUND)
	flags |= EW_NOTFOUND;
    if (options & WILD_ADD_SLASH)
	flags |= EW_ADDSLASH;
    if (options & WILD_KEEP_ALL)
	flags |= EW_KEEPALL;
    if (options & WILD_SILENT)
	flags |= EW_SILENT;
    if (options & WILD_NOERROR)
	flags |= EW_NOERROR;
    if (options & WILD_ALLLINKS)
	flags |= EW_ALLLINKS;

    if (xp->xp_context == EXPAND_FILES
	    || xp->xp_context == EXPAND_DIRECTORIES
	    || xp->xp_context == EXPAND_FILES_IN_PATH)
    {
	// Expand file or directory names.
	int	free_pat = FALSE;
	int	i;

	// for ":set path=" and ":set tags=" halve backslashes for escaped
	// space
	if (xp->xp_backslash != XP_BS_NONE)
	{
	    free_pat = TRUE;
	    pat = vim_strsave(pat);
	    for (i = 0; pat[i]; ++i)
		if (pat[i] == '\\')
		{
		    if (xp->xp_backslash == XP_BS_THREE
			    && pat[i + 1] == '\\'
			    && pat[i + 2] == '\\'
			    && pat[i + 3] == ' ')
			STRMOVE(pat + i, pat + i + 3);
		    if (xp->xp_backslash == XP_BS_ONE
			    && pat[i + 1] == ' ')
			STRMOVE(pat + i, pat + i + 1);
		}
	}

	if (xp->xp_context == EXPAND_FILES)
	    flags |= EW_FILE;
	else if (xp->xp_context == EXPAND_FILES_IN_PATH)
	    flags |= (EW_FILE | EW_PATH);
	else
	    flags = (flags | EW_DIR) & ~EW_FILE;
	if (options & WILD_ICASE)
	    flags |= EW_ICASE;

	// Expand wildcards, supporting %:h and the like.
	ret = expand_wildcards_eval(&pat, num_file, file, flags);
	if (free_pat)
	    vim_free(pat);
#ifdef BACKSLASH_IN_FILENAME
	if (p_csl[0] != NUL && (options & WILD_IGNORE_COMPLETESLASH) == 0)
	{
	    int	    i;

	    for (i = 0; i < *num_file; ++i)
	    {
		char_u	*ptr = (*file)[i];

		while (*ptr != NUL)
		{
		    if (p_csl[0] == 's' && *ptr == '\\')
			*ptr = '/';
		    else if (p_csl[0] == 'b' && *ptr == '/')
			*ptr = '\\';
		    ptr += (*mb_ptr2len)(ptr);
		}
	    }
	}
#endif
	return ret;
    }

    *file = (char_u **)"";
    *num_file = 0;
    if (xp->xp_context == EXPAND_HELP)
    {
	// With an empty argument we would get all the help tags, which is
	// very slow.  Get matches for "help" instead.
	if (find_help_tags(*pat == NUL ? (char_u *)"help" : pat,
						 num_file, file, FALSE) == OK)
	{
#ifdef FEAT_MULTI_LANG
	    cleanup_help_tags(*num_file, *file);
#endif
	    return OK;
	}
	return FAIL;
    }

    if (xp->xp_context == EXPAND_SHELLCMD)
	return expand_shellcmd(pat, num_file, file, flags);
    if (xp->xp_context == EXPAND_OLD_SETTING)
	return ExpandOldSetting(num_file, file);
    if (xp->xp_context == EXPAND_BUFFERS)
	return ExpandBufnames(pat, num_file, file, options);
#ifdef FEAT_DIFF
    if (xp->xp_context == EXPAND_DIFF_BUFFERS)
	return ExpandBufnames(pat, num_file, file, options | BUF_DIFF_FILTER);
#endif
    if (xp->xp_context == EXPAND_TAGS
	    || xp->xp_context == EXPAND_TAGS_LISTFILES)
	return expand_tags(xp->xp_context == EXPAND_TAGS, pat, num_file, file);
    if (xp->xp_context == EXPAND_COLORS)
    {
	char *directories[] = {"colors", NULL};
	return ExpandRTDir(pat, DIP_START + DIP_OPT, num_file, file,
								directories);
    }
    if (xp->xp_context == EXPAND_COMPILER)
    {
	char *directories[] = {"compiler", NULL};
	return ExpandRTDir(pat, 0, num_file, file, directories);
    }
    if (xp->xp_context == EXPAND_OWNSYNTAX)
    {
	char *directories[] = {"syntax", NULL};
	return ExpandRTDir(pat, 0, num_file, file, directories);
    }
    if (xp->xp_context == EXPAND_FILETYPE)
    {
	char *directories[] = {"syntax", "indent", "ftplugin", NULL};
	return ExpandRTDir(pat, 0, num_file, file, directories);
    }
# if defined(FEAT_EVAL)
    if (xp->xp_context == EXPAND_USER_LIST)
	return ExpandUserList(xp, num_file, file);
# endif
    if (xp->xp_context == EXPAND_PACKADD)
	return ExpandPackAddDir(pat, num_file, file);

    // When expanding a function name starting with s:, match the <SNR>nr_
    // prefix.
    if ((xp->xp_context == EXPAND_USER_FUNC
				       || xp->xp_context == EXPAND_DISASSEMBLE)
	    && STRNCMP(pat, "^s:", 3) == 0)
    {
	int len = (int)STRLEN(pat) + 20;

	tofree = alloc(len);
	vim_snprintf((char *)tofree, len, "^<SNR>\\d\\+_%s", pat + 3);
	pat = tofree;
    }

    regmatch.regprog = vim_regcomp(pat, magic_isset() ? RE_MAGIC : 0);
    if (regmatch.regprog == NULL)
	return FAIL;

    // set ignore-case according to p_ic, p_scs and pat
    regmatch.rm_ic = ignorecase(pat);

    if (xp->xp_context == EXPAND_SETTINGS
	    || xp->xp_context == EXPAND_BOOL_SETTINGS)
	ret = ExpandSettings(xp, &regmatch, num_file, file);
    else if (xp->xp_context == EXPAND_MAPPINGS)
	ret = ExpandMappings(&regmatch, num_file, file);
# if defined(FEAT_EVAL)
    else if (xp->xp_context == EXPAND_USER_DEFINED)
	ret = ExpandUserDefined(xp, &regmatch, num_file, file);
# endif
    else
    {
	static struct expgen
	{
	    int		context;
	    char_u	*((*func)(expand_T *, int));
	    int		ic;
	    int		escaped;
	} tab[] =
	{
	    {EXPAND_COMMANDS, get_command_name, FALSE, TRUE},
	    {EXPAND_BEHAVE, get_behave_arg, TRUE, TRUE},
	    {EXPAND_MAPCLEAR, get_mapclear_arg, TRUE, TRUE},
	    {EXPAND_MESSAGES, get_messages_arg, TRUE, TRUE},
	    {EXPAND_HISTORY, get_history_arg, TRUE, TRUE},
	    {EXPAND_USER_COMMANDS, get_user_commands, FALSE, TRUE},
	    {EXPAND_USER_ADDR_TYPE, get_user_cmd_addr_type, FALSE, TRUE},
	    {EXPAND_USER_CMD_FLAGS, get_user_cmd_flags, FALSE, TRUE},
	    {EXPAND_USER_NARGS, get_user_cmd_nargs, FALSE, TRUE},
	    {EXPAND_USER_COMPLETE, get_user_cmd_complete, FALSE, TRUE},
# ifdef FEAT_EVAL
	    {EXPAND_USER_VARS, get_user_var_name, FALSE, TRUE},
	    {EXPAND_FUNCTIONS, get_function_name, FALSE, TRUE},
	    {EXPAND_USER_FUNC, get_user_func_name, FALSE, TRUE},
	    {EXPAND_DISASSEMBLE, get_disassemble_argument, FALSE, TRUE},
	    {EXPAND_EXPRESSION, get_expr_name, FALSE, TRUE},
# endif
# ifdef FEAT_MENU
	    {EXPAND_MENUS, get_menu_name, FALSE, TRUE},
	    {EXPAND_MENUNAMES, get_menu_names, FALSE, TRUE},
# endif
# ifdef FEAT_SYN_HL
	    {EXPAND_SYNTAX, get_syntax_name, TRUE, TRUE},
# endif
# ifdef FEAT_PROFILE
	    {EXPAND_SYNTIME, get_syntime_arg, TRUE, TRUE},
# endif
	    {EXPAND_HIGHLIGHT, get_highlight_name, TRUE, TRUE},
	    {EXPAND_EVENTS, get_event_name, TRUE, FALSE},
	    {EXPAND_AUGROUP, get_augroup_name, TRUE, FALSE},
# ifdef FEAT_CSCOPE
	    {EXPAND_CSCOPE, get_cscope_name, TRUE, TRUE},
# endif
# ifdef FEAT_SIGNS
	    {EXPAND_SIGN, get_sign_name, TRUE, TRUE},
# endif
# ifdef FEAT_PROFILE
	    {EXPAND_PROFILE, get_profile_name, TRUE, TRUE},
# endif
# if defined(HAVE_LOCALE_H) || defined(X_LOCALE)
	    {EXPAND_LANGUAGE, get_lang_arg, TRUE, FALSE},
	    {EXPAND_LOCALES, get_locales, TRUE, FALSE},
# endif
	    {EXPAND_ENV_VARS, get_env_name, TRUE, TRUE},
	    {EXPAND_USER, get_users, TRUE, FALSE},
	    {EXPAND_ARGLIST, get_arglist_name, TRUE, FALSE},
	};
	int	i;

	// Find a context in the table and call the ExpandGeneric() with the
	// right function to do the expansion.
	ret = FAIL;
	for (i = 0; i < (int)ARRAY_LENGTH(tab); ++i)
	    if (xp->xp_context == tab[i].context)
	    {
		if (tab[i].ic)
		    regmatch.rm_ic = TRUE;
		ret = ExpandGeneric(xp, &regmatch, num_file, file,
						tab[i].func, tab[i].escaped);
		break;
	    }
    }

    vim_regfree(regmatch.regprog);
    vim_free(tofree);

    return ret;
}

/*
 * Expand a list of names.
 *
 * Generic function for command line completion.  It calls a function to
 * obtain strings, one by one.	The strings are matched against a regexp
 * program.  Matching strings are copied into an array, which is returned.
 *
 * Returns OK when no problems encountered, FAIL for error (out of memory).
 */
    static int
ExpandGeneric(
    expand_T	*xp,
    regmatch_T	*regmatch,
    int		*num_file,
    char_u	***file,
    char_u	*((*func)(expand_T *, int)),
					  // returns a string from the list
    int		escaped)
{
    int		i;
    int		count = 0;
    int		round;
    char_u	*str;

    // do this loop twice:
    // round == 0: count the number of matching names
    // round == 1: copy the matching names into allocated memory
    for (round = 0; round <= 1; ++round)
    {
	for (i = 0; ; ++i)
	{
	    str = (*func)(xp, i);
	    if (str == NULL)	    // end of list
		break;
	    if (*str == NUL)	    // skip empty strings
		continue;

	    if (vim_regexec(regmatch, str, (colnr_T)0))
	    {
		if (round)
		{
		    if (escaped)
			str = vim_strsave_escaped(str, (char_u *)" \t\\.");
		    else
			str = vim_strsave(str);
		    if (str == NULL)
		    {
			FreeWild(count, *file);
			*num_file = 0;
			*file = NULL;
			return FAIL;
		    }
		    (*file)[count] = str;
# ifdef FEAT_MENU
		    if (func == get_menu_names && str != NULL)
		    {
			// test for separator added by get_menu_names()
			str += STRLEN(str) - 1;
			if (*str == '\001')
			    *str = '.';
		    }
# endif
		}
		++count;
	    }
	}
	if (round == 0)
	{
	    if (count == 0)
		return OK;
	    *file = ALLOC_MULT(char_u *, count);
	    if (*file == NULL)
	    {
		*num_file = 0;
		*file = NULL;
		return FAIL;
	    }
	    *num_file = count;
	    count = 0;
	}
    }

    // Sort the results.  Keep menu's in the specified order.
    if (xp->xp_context != EXPAND_MENUNAMES && xp->xp_context != EXPAND_MENUS)
    {
	if (xp->xp_context == EXPAND_EXPRESSION
		|| xp->xp_context == EXPAND_FUNCTIONS
		|| xp->xp_context == EXPAND_USER_FUNC
		|| xp->xp_context == EXPAND_DISASSEMBLE)
	    // <SNR> functions should be sorted to the end.
	    qsort((void *)*file, (size_t)*num_file, sizeof(char_u *),
							   sort_func_compare);
	else
	    sort_strings(*file, *num_file);
    }

#if defined(FEAT_SYN_HL)
    // Reset the variables used for special highlight names expansion, so that
    // they don't show up when getting normal highlight names by ID.
    reset_expand_highlight();
#endif
    return OK;
}

/*
 * Complete a shell command.
 * Returns FAIL or OK;
 */
    static int
expand_shellcmd(
    char_u	*filepat,	// pattern to match with command names
    int		*num_file,	// return: number of matches
    char_u	***file,	// return: array with matches
    int		flagsarg)	// EW_ flags
{
    char_u	*pat;
    int		i;
    char_u	*path = NULL;
    int		mustfree = FALSE;
    garray_T    ga;
    char_u	*buf;
    size_t	l;
    char_u	*s, *e;
    int		flags = flagsarg;
    int		ret;
    int		did_curdir = FALSE;
    hashtab_T	found_ht;
    hashitem_T	*hi;
    hash_T	hash;

    buf = alloc(MAXPATHL);
    if (buf == NULL)
	return FAIL;

    // for ":set path=" and ":set tags=" halve backslashes for escaped space
    pat = vim_strsave(filepat);
    if (pat == NULL)
    {
	vim_free(buf);
	return FAIL;
    }

    for (i = 0; pat[i]; ++i)
	if (pat[i] == '\\' && pat[i + 1] == ' ')
	    STRMOVE(pat + i, pat + i + 1);

    flags |= EW_FILE | EW_EXEC | EW_SHELLCMD;

    if (pat[0] == '.' && (vim_ispathsep(pat[1])
			       || (pat[1] == '.' && vim_ispathsep(pat[2]))))
	path = (char_u *)".";
    else
    {
	// For an absolute name we don't use $PATH.
	if (!mch_isFullName(pat))
	    path = vim_getenv((char_u *)"PATH", &mustfree);
	if (path == NULL)
	    path = (char_u *)"";
    }

    // Go over all directories in $PATH.  Expand matches in that directory and
    // collect them in "ga".  When "." is not in $PATH also expand for the
    // current directory, to find "subdir/cmd".
    ga_init2(&ga, (int)sizeof(char *), 10);
    hash_init(&found_ht);
    for (s = path; ; s = e)
    {
# if defined(MSWIN)
	e = vim_strchr(s, ';');
# else
	e = vim_strchr(s, ':');
# endif
	if (e == NULL)
	    e = s + STRLEN(s);

	if (*s == NUL)
	{
	    if (did_curdir)
		break;
	    // Find directories in the current directory, path is empty.
	    did_curdir = TRUE;
	    flags |= EW_DIR;
	}
	else if (STRNCMP(s, ".", (int)(e - s)) == 0)
	{
	    did_curdir = TRUE;
	    flags |= EW_DIR;
	}
	else
	    // Do not match directories inside a $PATH item.
	    flags &= ~EW_DIR;

	l = e - s;
	if (l > MAXPATHL - 5)
	    break;
	vim_strncpy(buf, s, l);
	add_pathsep(buf);
	l = STRLEN(buf);
	vim_strncpy(buf + l, pat, MAXPATHL - 1 - l);

	// Expand matches in one directory of $PATH.
	ret = expand_wildcards(1, &buf, num_file, file, flags);
	if (ret == OK)
	{
	    if (ga_grow(&ga, *num_file) == FAIL)
		FreeWild(*num_file, *file);
	    else
	    {
		for (i = 0; i < *num_file; ++i)
		{
		    char_u *name = (*file)[i];

		    if (STRLEN(name) > l)
		    {
			// Check if this name was already found.
			hash = hash_hash(name + l);
			hi = hash_lookup(&found_ht, name + l, hash);
			if (HASHITEM_EMPTY(hi))
			{
			    // Remove the path that was prepended.
			    STRMOVE(name, name + l);
			    ((char_u **)ga.ga_data)[ga.ga_len++] = name;
			    hash_add_item(&found_ht, hi, name, hash);
			    name = NULL;
			}
		    }
		    vim_free(name);
		}
		vim_free(*file);
	    }
	}
	if (*e != NUL)
	    ++e;
    }
    *file = ga.ga_data;
    *num_file = ga.ga_len;

    vim_free(buf);
    vim_free(pat);
    if (mustfree)
	vim_free(path);
    hash_clear(&found_ht);
    return OK;
}

# if defined(FEAT_EVAL)
/*
 * Call "user_expand_func()" to invoke a user defined Vim script function and
 * return the result (either a string, a List or NULL).
 */
    static void *
call_user_expand_func(
    void	*(*user_expand_func)(char_u *, int, typval_T *),
    expand_T	*xp,
    int		*num_file,
    char_u	***file)
{
    cmdline_info_T	*ccline = get_cmdline_info();
    int		keep = 0;
    typval_T	args[4];
    sctx_T	save_current_sctx = current_sctx;
    char_u	*pat = NULL;
    void	*ret;

    if (xp->xp_arg == NULL || xp->xp_arg[0] == '\0' || xp->xp_line == NULL)
	return NULL;
    *num_file = 0;
    *file = NULL;

    if (ccline->cmdbuff != NULL)
    {
	keep = ccline->cmdbuff[ccline->cmdlen];
	ccline->cmdbuff[ccline->cmdlen] = 0;
    }

    pat = vim_strnsave(xp->xp_pattern, xp->xp_pattern_len);

    args[0].v_type = VAR_STRING;
    args[0].vval.v_string = pat;
    args[1].v_type = VAR_STRING;
    args[1].vval.v_string = xp->xp_line;
    args[2].v_type = VAR_NUMBER;
    args[2].vval.v_number = xp->xp_col;
    args[3].v_type = VAR_UNKNOWN;

    current_sctx = xp->xp_script_ctx;

    ret = user_expand_func(xp->xp_arg, 3, args);

    current_sctx = save_current_sctx;
    if (ccline->cmdbuff != NULL)
	ccline->cmdbuff[ccline->cmdlen] = keep;

    vim_free(pat);
    return ret;
}

/*
 * Expand names with a function defined by the user.
 */
    static int
ExpandUserDefined(
    expand_T	*xp,
    regmatch_T	*regmatch,
    int		*num_file,
    char_u	***file)
{
    char_u	*retstr;
    char_u	*s;
    char_u	*e;
    int		keep;
    garray_T	ga;
    int		skip;

    retstr = call_user_expand_func(call_func_retstr, xp, num_file, file);
    if (retstr == NULL)
	return FAIL;

    ga_init2(&ga, (int)sizeof(char *), 3);
    for (s = retstr; *s != NUL; s = e)
    {
	e = vim_strchr(s, '\n');
	if (e == NULL)
	    e = s + STRLEN(s);
	keep = *e;
	*e = NUL;

	skip = xp->xp_pattern[0] && vim_regexec(regmatch, s, (colnr_T)0) == 0;
	*e = keep;

	if (!skip)
	{
	    if (ga_grow(&ga, 1) == FAIL)
		break;
	    ((char_u **)ga.ga_data)[ga.ga_len] = vim_strnsave(s, e - s);
	    ++ga.ga_len;
	}

	if (*e != NUL)
	    ++e;
    }
    vim_free(retstr);
    *file = ga.ga_data;
    *num_file = ga.ga_len;
    return OK;
}

/*
 * Expand names with a list returned by a function defined by the user.
 */
    static int
ExpandUserList(
    expand_T	*xp,
    int		*num_file,
    char_u	***file)
{
    list_T      *retlist;
    listitem_T	*li;
    garray_T	ga;

    retlist = call_user_expand_func(call_func_retlist, xp, num_file, file);
    if (retlist == NULL)
	return FAIL;

    ga_init2(&ga, (int)sizeof(char *), 3);
    // Loop over the items in the list.
    FOR_ALL_LIST_ITEMS(retlist, li)
    {
	if (li->li_tv.v_type != VAR_STRING || li->li_tv.vval.v_string == NULL)
	    continue;  // Skip non-string items and empty strings

	if (ga_grow(&ga, 1) == FAIL)
	    break;

	((char_u **)ga.ga_data)[ga.ga_len] =
					 vim_strsave(li->li_tv.vval.v_string);
	++ga.ga_len;
    }
    list_unref(retlist);

    *file = ga.ga_data;
    *num_file = ga.ga_len;
    return OK;
}
# endif

/*
 * Expand "file" for all comma-separated directories in "path".
 * Adds the matches to "ga".  Caller must init "ga".
 */
    void
globpath(
    char_u	*path,
    char_u	*file,
    garray_T	*ga,
    int		expand_options)
{
    expand_T	xpc;
    char_u	*buf;
    int		i;
    int		num_p;
    char_u	**p;

    buf = alloc(MAXPATHL);
    if (buf == NULL)
	return;

    ExpandInit(&xpc);
    xpc.xp_context = EXPAND_FILES;

    // Loop over all entries in {path}.
    while (*path != NUL)
    {
	// Copy one item of the path to buf[] and concatenate the file name.
	copy_option_part(&path, buf, MAXPATHL, ",");
	if (STRLEN(buf) + STRLEN(file) + 2 < MAXPATHL)
	{
# if defined(MSWIN)
	    // Using the platform's path separator (\) makes vim incorrectly
	    // treat it as an escape character, use '/' instead.
	    if (*buf != NUL && !after_pathsep(buf, buf + STRLEN(buf)))
		STRCAT(buf, "/");
# else
	    add_pathsep(buf);
# endif
	    STRCAT(buf, file);
	    if (ExpandFromContext(&xpc, buf, &num_p, &p,
			     WILD_SILENT|expand_options) != FAIL && num_p > 0)
	    {
		ExpandEscape(&xpc, buf, num_p, p, WILD_SILENT|expand_options);

		if (ga_grow(ga, num_p) == OK)
		    // take over the pointers and put them in "ga"
		    for (i = 0; i < num_p; ++i)
		    {
			((char_u **)ga->ga_data)[ga->ga_len] = p[i];
			++ga->ga_len;
		    }
		vim_free(p);
	    }
	}
    }

    vim_free(buf);
}

#ifdef FEAT_WILDMENU

/*
 * Translate some keys pressed when 'wildmenu' is used.
 */
    int
wildmenu_translate_key(
	cmdline_info_T	*cclp,
	int		key,
	expand_T	*xp,
	int		did_wild_list)
{
    int c = key;

    if (did_wild_list && p_wmnu)
    {
	if (c == K_LEFT)
	    c = Ctrl_P;
	else if (c == K_RIGHT)
	    c = Ctrl_N;
    }
    // Hitting CR after "emenu Name.": complete submenu
    if (xp->xp_context == EXPAND_MENUNAMES && p_wmnu
	    && cclp->cmdpos > 1
	    && cclp->cmdbuff[cclp->cmdpos - 1] == '.'
	    && cclp->cmdbuff[cclp->cmdpos - 2] != '\\'
	    && (c == '\n' || c == '\r' || c == K_KENTER))
	c = K_DOWN;

    return c;
}

/*
 * Delete characters on the command line, from "from" to the current
 * position.
 */
    static void
cmdline_del(cmdline_info_T *cclp, int from)
{
    mch_memmove(cclp->cmdbuff + from, cclp->cmdbuff + cclp->cmdpos,
	    (size_t)(cclp->cmdlen - cclp->cmdpos + 1));
    cclp->cmdlen -= cclp->cmdpos - from;
    cclp->cmdpos = from;
}

/*
 * Handle a key pressed when wild menu is displayed
 */
    int
wildmenu_process_key(cmdline_info_T *cclp, int key, expand_T *xp)
{
    int		c = key;
    int		i;
    int		j;

    if (!p_wmnu)
	return c;

    // Special translations for 'wildmenu'
    if (xp->xp_context == EXPAND_MENUNAMES)
    {
	// Hitting <Down> after "emenu Name.": complete submenu
	if (c == K_DOWN && cclp->cmdpos > 0
		&& cclp->cmdbuff[cclp->cmdpos - 1] == '.')
	{
	    c = p_wc;
	    KeyTyped = TRUE;  // in case the key was mapped
	}
	else if (c == K_UP)
	{
	    // Hitting <Up>: Remove one submenu name in front of the
	    // cursor
	    int found = FALSE;

	    j = (int)(xp->xp_pattern - cclp->cmdbuff);
	    i = 0;
	    while (--j > 0)
	    {
		// check for start of menu name
		if (cclp->cmdbuff[j] == ' '
			&& cclp->cmdbuff[j - 1] != '\\')
		{
		    i = j + 1;
		    break;
		}
		// check for start of submenu name
		if (cclp->cmdbuff[j] == '.'
			&& cclp->cmdbuff[j - 1] != '\\')
		{
		    if (found)
		    {
			i = j + 1;
			break;
		    }
		    else
			found = TRUE;
		}
	    }
	    if (i > 0)
		cmdline_del(cclp, i);
	    c = p_wc;
	    KeyTyped = TRUE;  // in case the key was mapped
	    xp->xp_context = EXPAND_NOTHING;
	}
    }
    if ((xp->xp_context == EXPAND_FILES
		|| xp->xp_context == EXPAND_DIRECTORIES
		|| xp->xp_context == EXPAND_SHELLCMD))
    {
	char_u upseg[5];

	upseg[0] = PATHSEP;
	upseg[1] = '.';
	upseg[2] = '.';
	upseg[3] = PATHSEP;
	upseg[4] = NUL;

	if (c == K_DOWN
		&& cclp->cmdpos > 0
		&& cclp->cmdbuff[cclp->cmdpos - 1] == PATHSEP
		&& (cclp->cmdpos < 3
		    || cclp->cmdbuff[cclp->cmdpos - 2] != '.'
		    || cclp->cmdbuff[cclp->cmdpos - 3] != '.'))
	{
	    // go down a directory
	    c = p_wc;
	    KeyTyped = TRUE;  // in case the key was mapped
	}
	else if (STRNCMP(xp->xp_pattern, upseg + 1, 3) == 0 && c == K_DOWN)
	{
	    // If in a direct ancestor, strip off one ../ to go down
	    int found = FALSE;

	    j = cclp->cmdpos;
	    i = (int)(xp->xp_pattern - cclp->cmdbuff);
	    while (--j > i)
	    {
		if (has_mbyte)
		    j -= (*mb_head_off)(cclp->cmdbuff, cclp->cmdbuff + j);
		if (vim_ispathsep(cclp->cmdbuff[j]))
		{
		    found = TRUE;
		    break;
		}
	    }
	    if (found
		    && cclp->cmdbuff[j - 1] == '.'
		    && cclp->cmdbuff[j - 2] == '.'
		    && (vim_ispathsep(cclp->cmdbuff[j - 3]) || j == i + 2))
	    {
		cmdline_del(cclp, j - 2);
		c = p_wc;
		KeyTyped = TRUE;  // in case the key was mapped
	    }
	}
	else if (c == K_UP)
	{
	    // go up a directory
	    int found = FALSE;

	    j = cclp->cmdpos - 1;
	    i = (int)(xp->xp_pattern - cclp->cmdbuff);
	    while (--j > i)
	    {
		if (has_mbyte)
		    j -= (*mb_head_off)(cclp->cmdbuff, cclp->cmdbuff + j);
		if (vim_ispathsep(cclp->cmdbuff[j])
# ifdef BACKSLASH_IN_FILENAME
			&& vim_strchr((char_u *)" *?[{`$%#",
			    cclp->cmdbuff[j + 1]) == NULL
# endif
		   )
		{
		    if (found)
		    {
			i = j + 1;
			break;
		    }
		    else
			found = TRUE;
		}
	    }

	    if (!found)
		j = i;
	    else if (STRNCMP(cclp->cmdbuff + j, upseg, 4) == 0)
		j += 4;
	    else if (STRNCMP(cclp->cmdbuff + j, upseg + 1, 3) == 0
		    && j == i)
		j += 3;
	    else
		j = 0;
	    if (j > 0)
	    {
		// TODO this is only for DOS/UNIX systems - need to put in
		// machine-specific stuff here and in upseg init
		cmdline_del(cclp, j);
		put_on_cmdline(upseg + 1, 3, FALSE);
	    }
	    else if (cclp->cmdpos > i)
		cmdline_del(cclp, i);

	    // Now complete in the new directory. Set KeyTyped in case the
	    // Up key came from a mapping.
	    c = p_wc;
	    KeyTyped = TRUE;
	}
    }

    return c;
}

/*
 * Free expanded names when finished walking through the matches
 */
    void
wildmenu_cleanup(cmdline_info_T *cclp)
{
    int skt = KeyTyped;
    int old_RedrawingDisabled = RedrawingDisabled;

    if (!p_wmnu || wild_menu_showing == 0)
	return;

    if (cclp->input_fn)
	RedrawingDisabled = 0;

    if (wild_menu_showing == WM_SCROLLED)
    {
	// Entered command line, move it up
	cmdline_row--;
	redrawcmd();
    }
    else if (save_p_ls != -1)
    {
	// restore 'laststatus' and 'winminheight'
	p_ls = save_p_ls;
	p_wmh = save_p_wmh;
	last_status(FALSE);
	update_screen(VALID);	// redraw the screen NOW
	redrawcmd();
	save_p_ls = -1;
    }
    else
    {
	win_redraw_last_status(topframe);
	redraw_statuslines();
    }
    KeyTyped = skt;
    wild_menu_showing = 0;
    if (cclp->input_fn)
	RedrawingDisabled = old_RedrawingDisabled;
}
#endif

#if defined(FEAT_EVAL) || defined(PROTO)
/*
 * "getcompletion()" function
 */
    void
f_getcompletion(typval_T *argvars, typval_T *rettv)
{
    char_u	*pat;
    char_u	*type;
    expand_T	xpc;
    int		filtered = FALSE;
    int		options = WILD_SILENT | WILD_USE_NL | WILD_ADD_SLASH
								| WILD_NO_BEEP;

    if (in_vim9script()
	    && (check_for_string_arg(argvars, 0) == FAIL
		|| check_for_string_arg(argvars, 1) == FAIL
		|| check_for_opt_bool_arg(argvars, 2) == FAIL))
	return;

    if (argvars[1].v_type != VAR_STRING)
    {
	semsg(_(e_invarg2), "type must be a string");
	return;
    }
    type = tv_get_string(&argvars[1]);

    if (argvars[2].v_type != VAR_UNKNOWN)
	filtered = tv_get_bool_chk(&argvars[2], NULL);

    if (p_wic)
	options |= WILD_ICASE;

    // For filtered results, 'wildignore' is used
    if (!filtered)
	options |= WILD_KEEP_ALL;

    ExpandInit(&xpc);
    if (STRCMP(type, "cmdline") == 0)
    {
	set_one_cmd_context(&xpc, tv_get_string(&argvars[0]));
	xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
    }
    else
    {
	xpc.xp_pattern = tv_get_string(&argvars[0]);
	xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);

	xpc.xp_context = cmdcomplete_str_to_type(type);
	if (xpc.xp_context == EXPAND_NOTHING)
	{
	    semsg(_(e_invarg2), type);
	    return;
	}

# if defined(FEAT_MENU)
	if (xpc.xp_context == EXPAND_MENUS)
	{
	    set_context_in_menu_cmd(&xpc, (char_u *)"menu", xpc.xp_pattern, FALSE);
	    xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
	}
# endif
# ifdef FEAT_CSCOPE
	if (xpc.xp_context == EXPAND_CSCOPE)
	{
	    set_context_in_cscope_cmd(&xpc, xpc.xp_pattern, CMD_cscope);
	    xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
	}
# endif
# ifdef FEAT_SIGNS
	if (xpc.xp_context == EXPAND_SIGN)
	{
	    set_context_in_sign_cmd(&xpc, xpc.xp_pattern);
	    xpc.xp_pattern_len = (int)STRLEN(xpc.xp_pattern);
	}
# endif
    }

    pat = addstar(xpc.xp_pattern, xpc.xp_pattern_len, xpc.xp_context);
    if ((rettv_list_alloc(rettv) != FAIL) && (pat != NULL))
    {
	int	i;

	ExpandOne(&xpc, pat, NULL, options, WILD_ALL_KEEP);

	for (i = 0; i < xpc.xp_numfiles; i++)
	    list_append_string(rettv->vval.v_list, xpc.xp_files[i], -1);
    }
    vim_free(pat);
    ExpandCleanup(&xpc);
}
#endif // FEAT_EVAL