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" ==============================================================================
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" File: syntaxFolds.vim
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" Author: Srinath Avadhanula
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" ( srinath@fastmail.fm )
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" Last Change: Sun Oct 27 01:00 AM 2002 PST
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" Description: Emulation of the syntax folding capability of vim using manual
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" This script provides an emulation of the syntax folding of vim using manual
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" folding. Just as in syntax folding, the folds are defined by regions. Each
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" region is specified by a call to FoldRegions() which accepts 4 parameters:
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" call FoldRegions(startpat, endpat, startoff, endoff)
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" startpat: a line matching this pattern defines the beginning of a fold.
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" endpat : a line matching this pattern defines the end of a fold.
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" startoff: this is the offset from the starting line at which folding will
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" endoff : like startoff, but gives the offset of the actual fold end from
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" the line satisfying endpat.
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" startoff and endoff are necessary when the folding region does
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" not have a specific end pattern corresponding to a start
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" pattern. for example in latex,
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" defines the beginning of a section, but its not necessary to
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" have a corresponding
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" the section is assumed to end 1 line _before_ another section
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" startskip: a pattern which defines the beginning of a "skipped" region.
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" For example, suppose we define a \itemize fold as follows:
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" startpat = '^\s*\\item',
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" endpat = '^\s*\\item\|^\s*\\end{\(enumerate\|itemize\|description\)}',
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" This defines a fold which starts with a line beginning with an
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" \item and ending one line before a line beginning with an
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" \item or \end{enumerate} etc.
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" Then, as long as \item's are not nested things are fine.
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" However, once items begin to nest, the fold started by one
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" \item can end because of an \item in an \itemize
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" environment within this \item. i.e, the following can happen:
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" \item Some text <------- fold will start here
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" This item will contain a nested item
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" \begin{itemize} <----- fold will end here because next line contains \item...
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" \end{itemize} <----- ... instead of here.
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" \item Next item of the parent itemize
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" Therefore, in order to completely define a folding item which
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" allows nesting, we need to also define a "skip" pattern.
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" startskip and end skip do that.
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" Leave '' when there is no nesting.
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" endskip: the pattern which defines the end of the "skip" pattern for
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" 1. A syntax fold region for a latex section is
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" startpat = "\\section{"
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" endpat = "\\section{"
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" Note that the start and end patterns are thus the same and endoff has a
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" negative value to capture the effect of a section ending one line before
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" 2. A syntax fold region for the \itemize environment is:
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" startpat = '^\s*\\item',
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" endpat = '^\s*\\item\|^\s*\\end{\(enumerate\|itemize\|description\)}',
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" startskip = '^\s*\\begin{\(enumerate\|itemize\|description\)}',
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" endskip = '^\s*\\end{\(enumerate\|itemize\|description\)}'
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" Note the use of startskip and endskip to allow nesting.
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" Each time a call is made to FoldRegions(), all the regions (which might be
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" disjoint, but not nested) are folded up.
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" Nested folds can be created by successive calls to FoldRegions(). The first
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" call defines the region which is deepest in the folding. See MakeTexFolds()
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" for an idea of how this works for latex files.
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" Function: AddSyntaxFoldItem (start, end, startoff, endoff [, skipStart, skipEnd]) {{{
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function! AddSyntaxFoldItem(start, end, startoff, endoff, ...)
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if !exists('b:numFoldItems')
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let b:numFoldItems = 0
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let b:numFoldItems = b:numFoldItems + 1
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exe 'let b:startPat_'.b:numFoldItems.' = a:start'
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exe 'let b:endPat_'.b:numFoldItems.' = a:end'
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exe 'let b:startOff_'.b:numFoldItems.' = a:startoff'
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exe 'let b:endOff_'.b:numFoldItems.' = a:endoff'
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exe 'let b:skipStartPat_'.b:numFoldItems.' = skipStart'
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exe 'let b:skipEndPat_'.b:numFoldItems.' = skipEnd'
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" Function: MakeSyntaxFolds (force) {{{
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" Description: This function calls FoldRegions() several times with the
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" parameters specifying various regions resulting in a nested fold
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" structure for the file.
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function! MakeSyntaxFolds(force, ...)
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if exists('b:doneFolding') && a:force == 0
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let skipEndPattern = ''
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let skipEndPattern = '\|'.a:2
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if !exists('b:numFoldItems')
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b:numFoldItems = 1000000
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let maxline = line('.')
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while exists('b:startPat_'.i) && i <= b:numFoldItems
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exe 'let startPat = b:startPat_'.i
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exe 'let endPat = b:endPat_'.i
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exe 'let startOff = b:startOff_'.i
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exe 'let endOff = b:endOff_'.i
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if exists('b:skipStartPat_'.i)
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exe 'let skipStart = b:skipStartPat_'.i
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exe 'let skipEnd = b:skipEndPat_'.i
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call InitStack('BeginSkipArray')
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call FoldRegionsWithSkip(startPat, endPat, startOff, endOff, skipStart, skipEnd, 1, line('$'))
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" call PrintError('done folding ['.startPat.']')
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call FoldRegionsWithNoSkip(startPat, endPat, startOff, endOff, 1, line('$'), '')
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exe "normal! ".(foldlevel(r) - 1)."zo"
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let b:doneFolding = 0
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" FoldRegionsWithSkip: folding things such as \item's which can be nested. {{{
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function! FoldRegionsWithSkip(startpat, endpat, startoff, endoff, startskip, endskip, line1, line2)
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" count the regions which have been skipped as we go along. do not want to
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" create a fold which with a beginning or end line in one of the skipped
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let skippedRegions = ''
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" start searching for either the starting pattern or the end pattern.
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while search(a:startskip.'\|'.a:endskip, 'W')
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if getline('.') =~ a:endskip
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let lastBegin = Pop('BeginSkipArray')
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" call PrintError('popping '.lastBegin.' from stack and folding till '.line('.'))
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call FoldRegionsWithNoSkip(a:startpat, a:endpat, a:startoff, a:endoff, lastBegin, line('.'), skippedRegions)
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let skippedRegions = skippedRegions.lastBegin.','.line('.').'|'
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" if this is the beginning of a skip region, then, push this line as
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" the beginning of a skipped region.
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elseif getline('.') =~ a:startskip
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" call PrintError('pushing '.line('.').' ['.getline('.').'] into stack')
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call Push('BeginSkipArray', line('.'))
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" call PrintError('with skip starting at '.a:line1.' returning at line# '.line('.'))
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" FoldRegionsWithNoSkip: folding things such as \sections which do not nest. {{{
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function! FoldRegionsWithNoSkip(startpat, endpat, startoff, endoff, line1, line2, skippedRegions)
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" call PrintError('line1 = '.a:line1.', searching from '.line('.').'... for ['.a:startpat.'')
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let lineBegin = s:MySearch(a:startpat, 'in')
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" call PrintError('... and finding it at '.lineBegin)
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while lineBegin <= a:line2
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if IsInSkippedRegion(lineBegin, a:skippedRegions)
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let lineBegin = s:MySearch(a:startpat, 'out')
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" call PrintError(lineBegin.' is being skipped')
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let lineEnd = s:MySearch(a:endpat, 'out')
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while IsInSkippedRegion(lineEnd, a:skippedRegions) && lineEnd <= a:line2
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let lineEnd = s:MySearch(a:endpat, 'out')
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exe (lineBegin + a:startoff).','.a:line2.' fold'
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" call PrintError ('for ['.a:startpat.'] '.(lineBegin + a:startoff).','.(lineEnd + a:endoff).' fold')
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exe (lineBegin + a:startoff).','.(lineEnd + a:endoff).' fold'
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" call PrintError('line1 = '.a:line1.', searching from '.line('.').'... for ['.a:startpat.'')
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let lineBegin = s:MySearch(a:startpat, 'in')
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" call PrintError('... and finding it at '.lineBegin)
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" InitStack: initialize a stack {{{
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function! InitStack(name)
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exe 'let s:'.a:name.'_numElems = 0'
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" Push: push element into stack {{{
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function! Push(name, elem)
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exe 'let numElems = s:'.a:name.'_numElems'
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let numElems = numElems + 1
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exe 'let s:'.a:name.'_Element_'.numElems.' = a:elem'
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exe 'let s:'.a:name.'_numElems = numElems'
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" Pop: pops element off stack {{{
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exe 'let numElems = s:'.a:name.'_numElems'
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exe 'let ret = s:'.a:name.'_Element_'.numElems
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let numElems = numElems - 1
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exe 'let s:'.a:name.'_numElems = numElems'
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" MySearch: just like search(), but returns large number on failure {{{
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function! <SID>MySearch(pat, opt)
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if getline('.') =~ a:pat
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let ret = search(a:pat, 'W')
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let ret = search(a:pat, 'W')
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let ret = line('$') + 1
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" Function: IsInSkippedRegion (lnum, regions) {{{
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" Description: finds whether a given line number is within one of the regions
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function! IsInSkippedRegion(lnum, regions)
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let subset = s:Strntok(a:regions, '|', i)
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let n1 = s:Strntok(subset, ',', 1)
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let n2 = s:Strntok(subset, ',', 2)
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if a:lnum >= n1 && a:lnum <= n2
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let subset = s:Strntok(a:regions, '|', i)
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" Function: Strntok (string, tok, n) {{{
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" extract the n^th token from s seperated by tok.
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" example: Strntok('1,23,3', ',', 2) = 23
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fun! <SID>Strntok(s, tok, n)
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return matchstr( a:s.a:tok[0], '\v(\zs([^'.a:tok.']*)\ze['.a:tok.']){'.a:n.'}')
added
removed
vim/vim/plugin/SyntaxFolds.vim
