runtime/indent/r.vim

" Vim indent file
" Language:	R
" Author:	Jakson Alves de Aquino <jalvesaq@gmail.com>
" Last Change:	Wed Aug 31, 2011  12:24AM


" Only load this indent file when no other was loaded.
if exists("b:did_r_indent")
    finish
endif
let b:did_r_indent = 1

setlocal indentkeys=0{,0},:,!^F,o,O,e
setlocal indentexpr=GetRIndent()

" Only define the function once.
if exists("*GetRIndent")
    finish
endif

" Options to make the indentation more similar to Emacs/ESS:
if !exists("g:r_indent_align_args")
    let g:r_indent_align_args = 1
endif
if !exists("g:r_indent_ess_comments")
    let g:r_indent_ess_comments = 0
endif
if !exists("g:r_indent_comment_column")
    let g:r_indent_comment_column = 40
endif
if ! exists("g:r_indent_ess_compatible")
    let g:r_indent_ess_compatible = 0
endif

function s:RDelete_quotes(line)
    let i = 0
    let j = 0
    let line1 = ""
    let llen = strlen(a:line)
    while i < llen
        if a:line[i] == '"'
            let i += 1
            let line1 = line1 . 's'
            while !(a:line[i] == '"' && ((i > 1 && a:line[i-1] == '\' && a:line[i-2] == '\') || a:line[i-1] != '\')) && i < llen
                let i += 1
            endwhile
            if a:line[i] == '"'
                let i += 1
            endif
        else
            if a:line[i] == "'"
                let i += 1
                let line1 = line1 . 's'
                while !(a:line[i] == "'" && ((i > 1 && a:line[i-1] == '\' && a:line[i-2] == '\') || a:line[i-1] != '\')) && i < llen
                    let i += 1
                endwhile
                if a:line[i] == "'"
                    let i += 1
                endif
            else
                if a:line[i] == "`"
                    let i += 1
                    let line1 = line1 . 's'
                    while a:line[i] != "`" && i < llen
                        let i += 1
                    endwhile
                    if a:line[i] == "`"
                        let i += 1
                    endif
                endif
            endif
        endif
        if i == llen
            break
        endif
        let line1 = line1 . a:line[i]
        let j += 1
        let i += 1
    endwhile
    return line1
endfunction

" Convert foo(bar()) int foo()
function s:RDelete_parens(line)
    if s:Get_paren_balance(a:line, "(", ")") != 0
        return a:line
    endif
    let i = 0
    let j = 0
    let line1 = ""
    let llen = strlen(a:line)
    while i < llen
        let line1 = line1 . a:line[i]
        if a:line[i] == '('
            let nop = 1
            while nop > 0 && i < llen
                let i += 1
                if a:line[i] == ')'
                    let nop -= 1
                else
                    if a:line[i] == '('
                        let nop += 1 
                    endif
                endif
            endwhile
            let line1 = line1 . a:line[i]
        endif
        let i += 1
    endwhile
    return line1
endfunction

function! s:Get_paren_balance(line, o, c)
    let line2 = substitute(a:line, a:o, "", "g")
    let openp = strlen(a:line) - strlen(line2)
    let line3 = substitute(line2, a:c, "", "g")
    let closep = strlen(line2) - strlen(line3)
    return openp - closep
endfunction

function! s:Get_matching_brace(linenr, o, c, delbrace)
    let line = SanitizeRLine(getline(a:linenr))
    if a:delbrace == 1
        let line = substitute(line, '{$', "", "")
    endif
    let pb = s:Get_paren_balance(line, a:o, a:c)
    let i = a:linenr
    while pb != 0 && i > 1
        let i -= 1
        let pb += s:Get_paren_balance(SanitizeRLine(getline(i)), a:o, a:c)
    endwhile
    return i
endfunction

" This function is buggy because there 'if's without 'else'
" It must be rewritten relying more on indentation
function! s:Get_matching_if(linenr, delif)
"    let filenm = expand("%")
"    call writefile([filenm], "/tmp/matching_if_" . a:linenr)
    let line = SanitizeRLine(getline(a:linenr))
    if a:delif
        let line = substitute(line, "if", "", "g")
    endif
    let elsenr = 0
    let i = a:linenr
    let ifhere = 0
    while i > 0
        let line2 = substitute(line, '\<else\>', "xxx", "g")
        let elsenr += strlen(line) - strlen(line2)
        if line =~ '.*\s*if\s*()' || line =~ '.*\s*if\s*()'
            let elsenr -= 1
            if elsenr == 0
                let ifhere = i
                break
            endif
        endif
        let i -= 1
        let line = SanitizeRLine(getline(i))
    endwhile
    if ifhere
        return ifhere
    else
        return a:linenr
    endif
endfunction

function! s:Get_last_paren_idx(line, o, c, pb)
    let blc = a:pb
    let line = substitute(a:line, '\t', s:curtabstop, "g")
    let theidx = -1
    let llen = strlen(line)
    let idx = 0
    while idx < llen
        if line[idx] == a:o
            let blc -= 1
            if blc == 0
                let theidx = idx
            endif
        else
            if line[idx] == a:c
                let blc += 1
            endif
        endif
        let idx += 1
    endwhile
    return theidx + 1
endfunction

" Get previous relevant line. Search back until getting a line that isn't
" comment or blank
function s:Get_prev_line(lineno)
    let lnum = a:lineno - 1
    let data = getline( lnum )
    while lnum > 0 && (data =~ '^\s*#' || data =~ '^\s*$')
        let lnum = lnum - 1
        let data = getline( lnum )
    endwhile
    return lnum
endfunction

" This function is also used by r-plugin/common_global.vim
" Delete from '#' to the end of the line, unless the '#' is inside a string.
function SanitizeRLine(line)
    let newline = s:RDelete_quotes(a:line)
    let newline = s:RDelete_parens(newline)
    let newline = substitute(newline, '#.*', "", "")
    let newline = substitute(newline, '\s*$', "", "")
    return newline
endfunction

function GetRIndent()

    let clnum = line(".")    " current line

    let cline = getline(clnum)
    if cline =~ '^\s*#'
        if g:r_indent_ess_comments == 1
            if cline =~ '^\s*###'
                return 0
            endif
            if cline !~ '^\s*##'
                return g:r_indent_comment_column
            endif
        endif
    endif

    let cline = SanitizeRLine(cline)

    if cline =~ '^\s*}' || cline =~ '^\s*}\s*)$'
        let indline = s:Get_matching_brace(clnum, '{', '}', 1)
        if indline > 0 && indline != clnum
            let iline = SanitizeRLine(getline(indline))
            if s:Get_paren_balance(iline, "(", ")") == 0 || iline =~ '(\s*{$'
                return indent(indline)
            else
                let indline = s:Get_matching_brace(indline, '(', ')', 1)
                return indent(indline)
            endif
        endif
    endif

    " Find the first non blank line above the current line
    let lnum = s:Get_prev_line(clnum)
    " Hit the start of the file, use zero indent.
    if lnum == 0
        return 0
    endif

    let line = SanitizeRLine(getline(lnum))

    if &filetype == "rhelp"
        if cline =~ '^\\dontshow{' || cline =~ '^\\dontrun{' || cline =~ '^\\donttest{' || cline =~ '^\\testonly{'
            return 0
        endif
        if line =~ '^\\examples{' || line =~ '^\\usage{' || line =~ '^\\dontshow{' || line =~ '^\\dontrun{' || line =~ '^\\donttest{' || line =~ '^\\testonly{'
            return 0
        endif
        if line =~ '^\\method{.*}{.*}(.*'
            let line = substitute(line, '^\\method{\(.*\)}{.*}', '\1', "")
        endif
    endif

    if cline =~ '^\s*{'
        if g:r_indent_ess_compatible && line =~ ')$'
            let nlnum = lnum
            let nline = line
            while s:Get_paren_balance(nline, '(', ')') < 0
                let nlnum = s:Get_prev_line(nlnum)
                let nline = SanitizeRLine(getline(nlnum)) . nline
            endwhile
            if nline =~ '^\s*function\s*(' && indent(nlnum) == &sw
                return 0
            endif
        endif
        if s:Get_paren_balance(line, "(", ")") == 0
            return indent(lnum)
        endif
    endif

    " line is an incomplete command:
    if line =~ '\<\(if\|while\|for\|function\)\s*()$' || line =~ '\<else$' || line =~ '<-$'
        return indent(lnum) + &sw
    endif

    " Deal with () and []

    let pb = s:Get_paren_balance(line, '(', ')')

    if line =~ '^\s*{$' || line =~ '(\s*{' || (pb == 0 && (line =~ '{$' || line =~ '(\s*{$'))
        return indent(lnum) + &sw
    endif

    let bb = s:Get_paren_balance(line, '[', ']')

    let s:curtabstop = repeat(' ', &tabstop)
    if g:r_indent_align_args == 1

        if pb == 0 && bb == 0 && (line =~ '.*[,&|\-\*+<>]$' || cline =~ '^\s*[,&|\-\*+<>]')
            return indent(lnum)
        endif

        if pb > 0
            if &filetype == "rhelp"
                let ind = s:Get_last_paren_idx(line, '(', ')', pb)
            else
                let ind = s:Get_last_paren_idx(getline(lnum), '(', ')', pb)
            endif
            return ind
        endif

        if pb < 0 && line =~ '.*[,&|\-\*+<>]$'
            let lnum = s:Get_prev_line(lnum)
            while pb < 1 && lnum > 0
                let line = SanitizeRLine(getline(lnum))
                let line = substitute(line, '\t', s:curtabstop, "g")
                let ind = strlen(line)
                while ind > 0
                    if line[ind] == ')'
                        let pb -= 1
                    else
                        if line[ind] == '('
                            let pb += 1
                        endif
                    endif
                    if pb == 1
                        return ind + 1
                    endif
                    let ind -= 1
                endwhile
                let lnum -= 1
            endwhile
            return 0
        endif

        if bb > 0
            let ind = s:Get_last_paren_idx(getline(lnum), '[', ']', bb)
            return ind
        endif
    endif

    let post_block = 0
    if line =~ '}$'
        let lnum = s:Get_matching_brace(lnum, '{', '}', 0)
        let line = SanitizeRLine(getline(lnum))
        if lnum > 0 && line =~ '^\s*{'
            let lnum = s:Get_prev_line(lnum)
            let line = SanitizeRLine(getline(lnum))
        endif
        let pb = s:Get_paren_balance(line, '(', ')')
        let post_block = 1
    endif

    let post_fun = 0
    if pb < 0 && line !~ ')\s*[,&|\-\*+<>]$'
        let post_fun = 1
        while pb < 0 && lnum > 0
            let lnum -= 1
            let linepiece = SanitizeRLine(getline(lnum))
            let pb += s:Get_paren_balance(linepiece, "(", ")")
            let line = linepiece . line
        endwhile
        if line =~ '{$' && post_block == 0
            return indent(lnum) + &sw
        endif

        " Now we can do some tests again
        if cline =~ '^\s*{'
            return indent(lnum)
        endif
        if post_block == 0
            let newl = SanitizeRLine(line)
            if newl =~ '\<\(if\|while\|for\|function\)\s*()$' || newl =~ '\<else$' || newl =~ '<-$'
                return indent(lnum) + &sw
            endif
        endif
    endif

    if cline =~ '^\s*else'
        if line =~ '<-\s*if\s*()'
            return indent(lnum) + &sw
        else
            if line =~ '\<if\s*()'
                return indent(lnum)
            else
                return indent(lnum) - &sw
            endif
        endif
    endif

    if bb < 0 && line =~ '.*]'
        while bb < 0 && lnum > 0
            let lnum -= 1
            let linepiece = SanitizeRLine(getline(lnum))
            let bb += s:Get_paren_balance(linepiece, "[", "]")
            let line = linepiece . line
        endwhile
        let line = s:RDelete_parens(line)
    endif

    let plnum = s:Get_prev_line(lnum)
    let ppost_else = 0
    if plnum > 0
        let pline = SanitizeRLine(getline(plnum))
        let ppost_block = 0
        if pline =~ '}$'
            let ppost_block = 1
            let plnum = s:Get_matching_brace(plnum, '{', '}', 0)
            let pline = SanitizeRLine(getline(plnum))
            if pline =~ '^\s*{$' && plnum > 0
                let plnum = s:Get_prev_line(plnum)
                let pline = SanitizeRLine(getline(plnum))
            endif
        endif

        if pline =~ 'else$'
            let ppost_else = 1
            let plnum = s:Get_matching_if(plnum, 0)
            let pline = SanitizeRLine(getline(plnum))
        endif

        if pline =~ '^\s*else\s*if\s*('
            let pplnum = s:Get_prev_line(plnum)
            let ppline = SanitizeRLine(getline(pplnum))
            while ppline =~ '^\s*else\s*if\s*(' || ppline =~ '^\s*if\s*()\s*\S$'
                let plnum = pplnum
                let pline = ppline
                let pplnum = s:Get_prev_line(plnum)
                let ppline = SanitizeRLine(getline(pplnum))
            endwhile
            while ppline =~ '\<\(if\|while\|for\|function\)\s*()$' || ppline =~ '\<else$' || ppline =~ '<-$'
                let plnum = pplnum
                let pline = ppline
                let pplnum = s:Get_prev_line(plnum)
                let ppline = SanitizeRLine(getline(pplnum))
            endwhile
        endif

        let ppb = s:Get_paren_balance(pline, '(', ')')
        if ppb < 0 && (pline =~ ')\s*{$' || pline =~ ')$')
            while ppb < 0 && plnum > 0
                let plnum -= 1
                let linepiece = SanitizeRLine(getline(plnum))
                let ppb += s:Get_paren_balance(linepiece, "(", ")")
                let pline = linepiece . pline
            endwhile
            let pline = s:RDelete_parens(pline)
        endif
    endif

    let ind = indent(lnum)
    let pind = indent(plnum)

    if g:r_indent_align_args == 0 && pb != 0
        let ind += pb * &sw
        return ind
    endif

    if ind == pind || (ind == (pind  + &sw) && pline =~ '{$' && ppost_else == 0)
        return ind
    endif

    while pind < ind && plnum > 0 && ppb == 0
        let ind = pind
        let plnum = s:Get_prev_line(plnum)
        let pline = getline(plnum)
        let ppb = s:Get_paren_balance(pline, '(', ')')
        while pline =~ '^\s*else'
            let plnum = s:Get_matching_if(plnum, 1)
            let pline = getline(plnum)
            let ppb = s:Get_paren_balance(pline, '(', ')')
        endwhile
        let pind = indent(plnum)
        if ind == (pind  + &sw) && pline =~ '{$'
            return ind
        endif
    endwhile

    return ind

endfunction

" vim: sw=4