1 " ==============================================================================
2 " File: syntaxFolds.vim
3 " Author: Srinath Avadhanula
4 " ( srinath@fastmail.fm )
5 " Last Change: Sun Oct 27 01:00 AM 2002 PST
6 " Description: Emulation of the syntax folding capability of vim using manual
9 " This script provides an emulation of the syntax folding of vim using manual
10 " folding. Just as in syntax folding, the folds are defined by regions. Each
11 " region is specified by a call to FoldRegions() which accepts 4 parameters:
13 " call FoldRegions(startpat, endpat, startoff, endoff)
15 " startpat: a line matching this pattern defines the beginning of a fold.
16 " endpat : a line matching this pattern defines the end of a fold.
17 " startoff: this is the offset from the starting line at which folding will
19 " endoff : like startoff, but gives the offset of the actual fold end from
20 " the line satisfying endpat.
21 " startoff and endoff are necessary when the folding region does
22 " not have a specific end pattern corresponding to a start
23 " pattern. for example in latex,
25 " defines the beginning of a section, but its not necessary to
26 " have a corresponding
28 " the section is assumed to end 1 line _before_ another section
30 " startskip: a pattern which defines the beginning of a "skipped" region.
32 " For example, suppose we define a \itemize fold as follows:
33 " startpat = '^\s*\\item',
34 " endpat = '^\s*\\item\|^\s*\\end{\(enumerate\|itemize\|description\)}',
38 " This defines a fold which starts with a line beginning with an
39 " \item and ending one line before a line beginning with an
40 " \item or \end{enumerate} etc.
42 " Then, as long as \item's are not nested things are fine.
43 " However, once items begin to nest, the fold started by one
44 " \item can end because of an \item in an \itemize
45 " environment within this \item. i.e, the following can happen:
48 " \item Some text <------- fold will start here
49 " This item will contain a nested item
50 " \begin{itemize} <----- fold will end here because next line contains \item...
52 " \end{itemize} <----- ... instead of here.
53 " \item Next item of the parent itemize
56 " Therefore, in order to completely define a folding item which
57 " allows nesting, we need to also define a "skip" pattern.
58 " startskip and end skip do that.
59 " Leave '' when there is no nesting.
60 " endskip: the pattern which defines the end of the "skip" pattern for
64 " 1. A syntax fold region for a latex section is
65 " startpat = "\\section{"
66 " endpat = "\\section{"
71 " Note that the start and end patterns are thus the same and endoff has a
72 " negative value to capture the effect of a section ending one line before
74 " 2. A syntax fold region for the \itemize environment is:
75 " startpat = '^\s*\\item',
76 " endpat = '^\s*\\item\|^\s*\\end{\(enumerate\|itemize\|description\)}',
79 " startskip = '^\s*\\begin{\(enumerate\|itemize\|description\)}',
80 " endskip = '^\s*\\end{\(enumerate\|itemize\|description\)}'
81 " Note the use of startskip and endskip to allow nesting.
84 " Each time a call is made to FoldRegions(), all the regions (which might be
85 " disjoint, but not nested) are folded up.
86 " Nested folds can be created by successive calls to FoldRegions(). The first
87 " call defines the region which is deepest in the folding. See MakeTexFolds()
88 " for an idea of how this works for latex files.
90 " Function: AddSyntaxFoldItem (start, end, startoff, endoff [, skipStart, skipEnd]) {{{
91 function! AddSyntaxFoldItem(start, end, startoff, endoff, ...)
99 if !exists('b:numFoldItems')
100 let b:numFoldItems = 0
102 let b:numFoldItems = b:numFoldItems + 1
104 exe 'let b:startPat_'.b:numFoldItems.' = a:start'
105 exe 'let b:endPat_'.b:numFoldItems.' = a:end'
106 exe 'let b:startOff_'.b:numFoldItems.' = a:startoff'
107 exe 'let b:endOff_'.b:numFoldItems.' = a:endoff'
108 exe 'let b:skipStartPat_'.b:numFoldItems.' = skipStart'
109 exe 'let b:skipEndPat_'.b:numFoldItems.' = skipEnd'
114 " Function: MakeSyntaxFolds (force) {{{
115 " Description: This function calls FoldRegions() several times with the
116 " parameters specifying various regions resulting in a nested fold
117 " structure for the file.
118 function! MakeSyntaxFolds(force, ...)
119 if exists('b:doneFolding') && a:force == 0
123 let skipEndPattern = ''
126 let skipEndPattern = '\|'.a:2
135 if !exists('b:numFoldItems')
136 b:numFoldItems = 1000000
141 let maxline = line('.')
143 while exists('b:startPat_'.i) && i <= b:numFoldItems
144 exe 'let startPat = b:startPat_'.i
145 exe 'let endPat = b:endPat_'.i
146 exe 'let startOff = b:startOff_'.i
147 exe 'let endOff = b:endOff_'.i
151 if exists('b:skipStartPat_'.i)
152 exe 'let skipStart = b:skipStartPat_'.i
153 exe 'let skipEnd = b:skipEndPat_'.i
159 call InitStack('BeginSkipArray')
160 call FoldRegionsWithSkip(startPat, endPat, startOff, endOff, skipStart, skipEnd, 1, line('$'))
161 " call PrintError('done folding ['.startPat.']')
163 call FoldRegionsWithNoSkip(startPat, endPat, startOff, endOff, 1, line('$'), '')
175 exe "normal! ".(foldlevel(r) - 1)."zo"
177 let b:doneFolding = 0
183 " FoldRegionsWithSkip: folding things such as \item's which can be nested. {{{
184 function! FoldRegionsWithSkip(startpat, endpat, startoff, endoff, startskip, endskip, line1, line2)
186 " count the regions which have been skipped as we go along. do not want to
187 " create a fold which with a beginning or end line in one of the skipped
189 let skippedRegions = ''
191 " start searching for either the starting pattern or the end pattern.
192 while search(a:startskip.'\|'.a:endskip, 'W')
194 if getline('.') =~ a:endskip
196 let lastBegin = Pop('BeginSkipArray')
197 " call PrintError('popping '.lastBegin.' from stack and folding till '.line('.'))
198 call FoldRegionsWithNoSkip(a:startpat, a:endpat, a:startoff, a:endoff, lastBegin, line('.'), skippedRegions)
199 let skippedRegions = skippedRegions.lastBegin.','.line('.').'|'
202 " if this is the beginning of a skip region, then, push this line as
203 " the beginning of a skipped region.
204 elseif getline('.') =~ a:startskip
206 " call PrintError('pushing '.line('.').' ['.getline('.').'] into stack')
207 call Push('BeginSkipArray', line('.'))
212 " call PrintError('with skip starting at '.a:line1.' returning at line# '.line('.'))
216 " FoldRegionsWithNoSkip: folding things such as \sections which do not nest. {{{
217 function! FoldRegionsWithNoSkip(startpat, endpat, startoff, endoff, line1, line2, skippedRegions)
220 " call PrintError('line1 = '.a:line1.', searching from '.line('.').'... for ['.a:startpat.'')
221 let lineBegin = s:MySearch(a:startpat, 'in')
222 " call PrintError('... and finding it at '.lineBegin)
224 while lineBegin <= a:line2
225 if IsInSkippedRegion(lineBegin, a:skippedRegions)
226 let lineBegin = s:MySearch(a:startpat, 'out')
227 " call PrintError(lineBegin.' is being skipped')
230 let lineEnd = s:MySearch(a:endpat, 'out')
231 while IsInSkippedRegion(lineEnd, a:skippedRegions) && lineEnd <= a:line2
232 let lineEnd = s:MySearch(a:endpat, 'out')
235 exe (lineBegin + a:startoff).','.a:line2.' fold'
238 " call PrintError ('for ['.a:startpat.'] '.(lineBegin + a:startoff).','.(lineEnd + a:endoff).' fold')
239 exe (lineBegin + a:startoff).','.(lineEnd + a:endoff).' fold'
242 " call PrintError('line1 = '.a:line1.', searching from '.line('.').'... for ['.a:startpat.'')
243 let lineBegin = s:MySearch(a:startpat, 'in')
244 " call PrintError('... and finding it at '.lineBegin)
252 " InitStack: initialize a stack {{{
253 function! InitStack(name)
254 exe 'let s:'.a:name.'_numElems = 0'
257 " Push: push element into stack {{{
258 function! Push(name, elem)
259 exe 'let numElems = s:'.a:name.'_numElems'
260 let numElems = numElems + 1
261 exe 'let s:'.a:name.'_Element_'.numElems.' = a:elem'
262 exe 'let s:'.a:name.'_numElems = numElems'
265 " Pop: pops element off stack {{{
267 exe 'let numElems = s:'.a:name.'_numElems'
271 exe 'let ret = s:'.a:name.'_Element_'.numElems
272 let numElems = numElems - 1
273 exe 'let s:'.a:name.'_numElems = numElems'
278 " MySearch: just like search(), but returns large number on failure {{{
279 function! <SID>MySearch(pat, opt)
281 if getline('.') =~ a:pat
284 let ret = search(a:pat, 'W')
288 let ret = search(a:pat, 'W')
292 let ret = line('$') + 1
297 " Function: IsInSkippedRegion (lnum, regions) {{{
298 " Description: finds whether a given line number is within one of the regions
300 function! IsInSkippedRegion(lnum, regions)
302 let subset = s:Strntok(a:regions, '|', i)
304 let n1 = s:Strntok(subset, ',', 1)
305 let n2 = s:Strntok(subset, ',', 2)
306 if a:lnum >= n1 && a:lnum <= n2
310 let subset = s:Strntok(a:regions, '|', i)
316 " Function: Strntok (string, tok, n) {{{
317 " extract the n^th token from s seperated by tok.
318 " example: Strntok('1,23,3', ',', 2) = 23
319 fun! <SID>Strntok(s, tok, n)
320 return matchstr( a:s.a:tok[0], '\v(\zs([^'.a:tok.']*)\ze['.a:tok.']){'.a:n.'}')