Change latex provider to luatex, closes #476

autoload/vimtex/fold/cmd_addplot.vim

@@ -0,0 +1,51 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'latex') == -1
+
+" vimtex - LaTeX plugin for Vim
+"
+" Maintainer: Karl Yngve Lervåg
+" Email:      karl.yngve@gmail.com
+"
+
+function! vimtex#fold#cmd_addplot#new(config) abort " {{{1
+  return extend(deepcopy(s:folder), a:config).init()
+endfunction
+
+" }}}1
+
+
+let s:folder = {
+      \ 'name' : 'cmd_addplot',
+      \ 're' : {},
+      \ 'opened' : 0,
+      \ 'cmds' : [],
+      \}
+function! s:folder.init() abort dict " {{{1
+  let l:re = '\v^\s*\\%(' . join(self.cmds, '|') . ')\s*%(\[[^\]]*\])?'
+
+  let self.re.start = l:re . '\s*\w+\s*%(\[[^\]]*\])?\s*\ze\{\s*%($|\%)'
+  let self.re.end = '^\s*}'
+  let self.re.fold_re = '\\%(' . join(self.cmds, '|') . ')'
+
+  return self
+endfunction
+
+" }}}1
+function! s:folder.level(line, lnum) abort dict " {{{1
+  if a:line =~# self.re.start
+    let self.opened = 1
+    return 'a1'
+  elseif self.opened && a:line =~# self.re.end
+    let self.opened = 0
+    return 's1'
+  endif
+endfunction
+
+" }}}1
+function! s:folder.text(line, level) abort dict " {{{1
+  return matchstr(a:line, self.re.start) . '{...}'
+        \ . substitute(getline(v:foldend), self.re.end, '', '')
+endfunction
+
+" }}}1
+
+endif

autoload/vimtex/fold/cmd_multi.vim

@@ -0,0 +1,51 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'latex') == -1
+
+" vimtex - LaTeX plugin for Vim
+"
+" Maintainer: Karl Yngve Lervåg
+" Email:      karl.yngve@gmail.com
+"
+
+function! vimtex#fold#cmd_multi#new(config) abort " {{{1
+  return extend(deepcopy(s:folder), a:config).init()
+endfunction
+
+" }}}1
+
+
+let s:folder = {
+      \ 'name' : 'cmd_multi',
+      \ 're' : {},
+      \ 'opened' : 0,
+      \ 'cmds' : [],
+      \}
+function! s:folder.init() abort dict " {{{1
+  let l:re = '\v^\s*\\%(' . join(self.cmds, '|') . ')\*?'
+
+  let self.re.start = l:re . '.*(\{|\[)\s*(\%.*)?$'
+  let self.re.end = '\v^\s*%(\}\s*\{)*\}\s*%(\%|$)'
+  let self.re.text = l:re . '\{[^}]*\}'
+  let self.re.fold_re = '\\%(' . join(self.cmds, '|') . ')'
+
+  return self
+endfunction
+
+" }}}1
+function! s:folder.level(line, lnum) abort dict " {{{1
+  if a:line =~# self.re.start
+    let self.opened += 1
+    return 'a1'
+  elseif self.opened > 0 && a:line =~# self.re.end
+    let self.opened -= 1
+    return 's1'
+  endif
+endfunction
+
+" }}}1
+function! s:folder.text(line, level) abort dict " {{{1
+  return a:line
+endfunction
+
+" }}}1
+
+endif

autoload/vimtex/fold/cmd_single.vim

@@ -0,0 +1,52 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'latex') == -1
+
+" vimtex - LaTeX plugin for Vim
+"
+" Maintainer: Karl Yngve Lervåg
+" Email:      karl.yngve@gmail.com
+"
+
+function! vimtex#fold#cmd_single#new(config) abort " {{{1
+  return extend(deepcopy(s:folder), a:config).init()
+endfunction
+
+" }}}1
+
+
+let s:folder = {
+      \ 'name' : 'cmd_single',
+      \ 're' : {},
+      \ 'opened' : 0,
+      \ 'cmds' : [],
+      \}
+function! s:folder.init() abort dict " {{{1
+  let l:re = '\v^\s*\\%(' . join(self.cmds, '|') . ')\*?\s*%(\[.*\])?'
+
+  let self.re.start = l:re . '\s*\{\s*%($|\%)'
+  let self.re.end = '^\s*}'
+  let self.re.text = l:re
+  let self.re.fold_re = '\\%(' . join(self.cmds, '|') . ')'
+
+  return self
+endfunction
+
+" }}}1
+function! s:folder.level(line, lnum) abort dict " {{{1
+  if a:line =~# self.re.start
+    let self.opened = 1
+    return 'a1'
+  elseif self.opened && a:line =~# self.re.end
+    let self.opened = 0
+    return 's1'
+  endif
+endfunction
+
+" }}}1
+function! s:folder.text(line, level) abort dict " {{{1
+  return matchstr(a:line, self.re.text) . '{...}'
+        \ . substitute(getline(v:foldend), self.re.end, '', '')
+endfunction
+
+" }}}1
+
+endif

autoload/vimtex/fold/cmd_single_opt.vim

@@ -0,0 +1,53 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'latex') == -1
+
+" vimtex - LaTeX plugin for Vim
+"
+" Maintainer: Karl Yngve Lervåg
+" Email:      karl.yngve@gmail.com
+"
+
+function! vimtex#fold#cmd_single_opt#new(config) abort " {{{1
+  return extend(deepcopy(s:folder), a:config).init()
+endfunction
+
+" }}}1
+
+
+let s:folder = {
+      \ 'name' : 'cmd_single_opt',
+      \ 're' : {},
+      \ 'opened' : 0,
+      \ 'cmds' : [],
+      \}
+function! s:folder.init() abort dict " {{{1
+  let l:re = '\v^\s*\\%(' . join(self.cmds, '|') . ')\*?'
+
+  let self.re.start = l:re . '\s*\[\s*%($|\%)'
+  let self.re.end = '^\s*\]{'
+  let self.re.text = l:re
+  let self.re.fold_re = '\\%(' . join(self.cmds, '|') . ')'
+
+  return self
+endfunction
+
+" }}}1
+function! s:folder.level(line, lnum) abort dict " {{{1
+  if a:line =~# self.re.start
+    let self.opened = 1
+    return 'a1'
+  elseif self.opened && a:line =~# self.re.end
+    let self.opened = 0
+    return 's1'
+  endif
+endfunction
+
+" }}}1
+function! s:folder.text(line, level) abort dict " {{{1
+  let l:col = strlen(matchstr(a:line, '^\s*')) + 1
+  return matchstr(a:line, self.re.text) . '[...]{'
+        \ . vimtex#cmd#get_at(v:foldstart, l:col).args[0].text . '}'
+endfunction
+
+" }}}1
+
+endif

autoload/vimtex/fold/comments.vim

@@ -0,0 +1,46 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'latex') == -1
+
+" vimtex - LaTeX plugin for Vim
+"
+" Maintainer: Karl Yngve Lervåg
+" Email:      karl.yngve@gmail.com
+"
+
+function! vimtex#fold#comments#new(config) abort " {{{1
+  return extend(deepcopy(s:folder), a:config)
+endfunction
+
+" }}}1
+
+
+let s:folder = {
+      \ 'name' : 'comments',
+      \ 're' : {'start' : '^\s*%'},
+      \ 'opened' : 0,
+      \}
+function! s:folder.level(line, lnum) abort dict " {{{1
+  if exists('b:vimtex.fold_types_dict.markers.opened')
+        \ && b:vimtex.fold_types_dict.markers.opened | return | endif
+
+  if a:line =~# self.re.start
+    let l:next = getline(a:lnum-1) !~# self.re.start
+    let l:prev = getline(a:lnum+1) !~# self.re.start
+    if l:next && !l:prev
+      let self.opened = 1
+      return 'a1'
+    elseif l:prev && !l:next
+      let self.opened = 0
+      return 's1'
+    endif
+  endif
+endfunction
+
+" }}}1
+function! s:folder.text(line, level) abort dict " {{{1
+  let l:lines = map(getline(v:foldstart, v:foldend), 'matchstr(v:val, ''%\s*\zs.*\ze\s*'')')
+  return matchstr(a:line, '^.*\s*%') . join(l:lines, ' ')
+endfunction
+
+" }}}1
+
+endif

autoload/vimtex/fold/env_options.vim

@@ -0,0 +1,53 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'latex') == -1
+
+" vimtex - LaTeX plugin for Vim
+"
+" Maintainer: Karl Yngve Lervåg
+" Email:      karl.yngve@gmail.com
+"
+
+function! vimtex#fold#env_options#new(config) abort " {{{1
+  return extend(deepcopy(s:folder), a:config)
+endfunction
+
+" }}}1
+
+
+let s:folder = {
+      \ 'name' : 'envs with options',
+      \ 're' : {
+      \   'start' : g:vimtex#re#not_comment . '\\begin\s*\{.{-}\}\[\s*($|\%)',
+      \   'end' : '\s*\]\s*$',
+      \ },
+      \ 'opened' : 0,
+      \}
+function! s:folder.level(line, lnum) abort dict " {{{1
+  return self.opened
+        \ ? self.fold_closed(a:line, a:lnum)
+        \ : self.fold_opened(a:line, a:lnum)
+endfunction
+
+" }}}1
+function! s:folder.fold_opened(line, lnum) abort dict " {{{1
+  if a:line =~# self.re.start
+    let self.opened = 1
+    return 'a1'
+  endif
+endfunction
+
+" }}}1
+function! s:folder.fold_closed(line, lnum) abort dict " {{{1
+  if a:line =~# self.re.end
+    let self.opened = 0
+    return 's1'
+  endif
+endfunction
+
+" }}}1
+function! s:folder.text(line, level) abort dict " {{{1
+  return a:line . '...] '
+endfunction
+
+" }}}1
+
+endif

autoload/vimtex/fold/envs.vim

@@ -0,0 +1,188 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'latex') == -1
+
+" vimtex - LaTeX plugin for Vim
+"
+" Maintainer: Karl Yngve Lervåg
+" Email:      karl.yngve@gmail.com
+"
+
+function! vimtex#fold#envs#new(config) abort " {{{1
+  return extend(deepcopy(s:folder), a:config).init()
+endfunction
+
+" }}}1
+
+
+let s:folder = {
+      \ 'name' : 'environments',
+      \ 're' : {
+      \   'start' : g:vimtex#re#not_comment . '\\begin\s*\{.{-}\}',
+      \   'end' : g:vimtex#re#not_comment . '\\end\s*\{.{-}\}',
+      \   'name' : g:vimtex#re#not_comment . '\\%(begin|end)\s*\{\zs.{-}\ze\}'
+      \ },
+      \ 'whitelist' : [],
+      \ 'blacklist' : [],
+      \}
+function! s:folder.init() abort dict " {{{1
+  " Define the validator as simple as possible
+  if empty(self.whitelist) && empty(self.blacklist)
+    function! self.validate(env) abort dict
+      return 1
+    endfunction
+  elseif empty(self.whitelist)
+    function! self.validate(env) abort dict
+      return index(self.blacklist, a:env) < 0
+    endfunction
+  elseif empty(self.blacklist)
+    function! self.validate(env) abort dict
+      return index(self.whitelist, a:env) >= 0
+    endfunction
+  else
+    function! self.validate(env) abort dict
+      return index(self.whitelist, a:env) >= 0 && index(self.blacklist, a:env) < 0
+    endfunction
+  endif
+
+  return self
+endfunction
+
+" }}}1
+function! s:folder.level(line, lnum) abort dict " {{{1
+  let l:env = matchstr(a:line, self.re.name)
+
+  if !empty(l:env) && self.validate(l:env)
+    if a:line =~# self.re.start
+      if a:line !~# '\\end'
+        return 'a1'
+      endif
+    elseif a:line =~# self.re.end
+      if a:line !~# '\\begin'
+        return 's1'
+      endif
+    endif
+  endif
+endfunction
+
+" }}}1
+function! s:folder.text(line, level) abort dict " {{{1
+  let env = matchstr(a:line, self.re.name)
+  if !self.validate(env) | return | endif
+
+  " Set caption/label based on type of environment
+  if env ==# 'frame'
+    let label = ''
+    let caption = self.parse_caption_frame(a:line)
+  elseif env ==# 'table'
+    let label = self.parse_label()
+    let caption = self.parse_caption_table(a:line)
+  else
+    let label = self.parse_label()
+    let caption = self.parse_caption(a:line)
+  endif
+
+  let width_ind = len(matchstr(a:line, '^\s*'))
+  let width = winwidth(0) - (&number ? &numberwidth : 0) - 4 - width_ind
+
+  let width_env = 19
+  let width_lab = len(label) + 2 > width - width_env
+        \ ? width - width_env
+        \ : len(label) + 2
+  let width_cap = width - width_env - width_lab
+
+  if !empty(label)
+    let label = printf('(%.*S)', width_lab, label)
+  endif
+
+  if !empty(caption)
+    if strchars(caption) > width_cap
+      let caption = strpart(caption, 0, width_cap - 4) . '...'
+    endif
+  else
+    let width_env += width_cap
+    let width_cap = 0
+  endif
+
+  if strlen(env) > width_env - 8
+    let env = strpart(env, 0, width_env - 11) . '...'
+  endif
+  let env = '\begin{' . env . '}'
+
+  let title = printf('%*S%-*S %-*S  %*S',
+        \ width_ind, '',
+        \ width_env, env,
+        \ width_cap, caption,
+        \ width_lab, label)
+
+  return substitute(title, '\s\+$', '', '')
+endfunction
+
+" }}}1
+function! s:folder.parse_label() abort dict " {{{1
+  let i = v:foldend
+  while i >= v:foldstart
+    if getline(i) =~# '^\s*\\label'
+      return matchstr(getline(i), '^\s*\\label\%(\[.*\]\)\?{\zs.*\ze}')
+    end
+    let i -= 1
+  endwhile
+  return ''
+endfunction
+
+" }}}1
+function! s:folder.parse_caption(line) abort dict " {{{1
+  let i = v:foldend
+  while i >= v:foldstart
+    if getline(i) =~# '^\s*\\caption'
+      return matchstr(getline(i),
+            \ '^\s*\\caption\(\[.*\]\)\?{\zs.\{-1,}\ze\(}\s*\)\?$')
+    end
+    let i -= 1
+  endwhile
+
+  " If no caption found, check for a caption comment
+  return matchstr(a:line,'\\begin\*\?{.*}\s*%\s*\zs.*')
+endfunction
+
+" }}}1
+function! s:folder.parse_caption_table(line) abort dict " {{{1
+  let i = v:foldstart
+  while i <= v:foldend
+    if getline(i) =~# '^\s*\\caption'
+      return matchstr(getline(i),
+            \ '^\s*\\caption\s*\(\[.*\]\)\?\s*{\zs.\{-1,}\ze\(}\s*\)\?$')
+    end
+    let i += 1
+  endwhile
+
+  " If no caption found, check for a caption comment
+  return matchstr(a:line,'\\begin\*\?{.*}\s*%\s*\zs.*')
+endfunction
+
+" }}}1
+function! s:folder.parse_caption_frame(line) abort dict " {{{1
+  " Test simple variants first
+  let caption1 = matchstr(a:line,'\\begin\*\?{.*}\(\[[^]]*\]\)\?{\zs.\+\ze}')
+  let caption2 = matchstr(a:line,'\\begin\*\?{.*}\(\[[^]]*\]\)\?{\zs.\+')
+  if !empty(caption1)
+    return caption1
+  elseif !empty(caption2)
+    return caption2
+  endif
+
+  " Search for \frametitle command
+  let i = v:foldstart
+  while i <= v:foldend
+    if getline(i) =~# '^\s*\\frametitle'
+      return matchstr(getline(i),
+            \ '^\s*\\frametitle\(\[.*\]\)\?{\zs.\{-1,}\ze\(}\s*\)\?$')
+    end
+    let i += 1
+  endwhile
+
+  " If no caption found, check for a caption comment
+  return matchstr(a:line,'\\begin\*\?{.*}\s*%\s*\zs.*')
+endfunction
+
+" }}}1
+
+endif

autoload/vimtex/fold/markers.vim

@@ -0,0 +1,60 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'latex') == -1
+
+" vimtex - LaTeX plugin for Vim
+"
+" Maintainer: Karl Yngve Lervåg
+" Email:      karl.yngve@gmail.com
+"
+
+function! vimtex#fold#markers#new(config) abort " {{{1
+  return extend(deepcopy(s:folder), a:config).init()
+endfunction
+
+" }}}1
+
+
+let s:folder = {
+      \ 'name' : 'markers',
+      \ 'open' : '{{{',
+      \ 'close' : '}}}',
+      \ 're' : {},
+      \ 'opened' : 0,
+      \}
+function! s:folder.init() abort dict " {{{1
+  let self.re.start = '%.*' . self.open
+  let self.re.end = '%.*' . self.close
+  let self.re.text = [
+        \ [self.re.start . '\d\?\s*\zs.*', '% ' . self.open . ' '],
+        \ ['%\s*\zs.*\ze' . self.open, '% ' . self.open . ' '],
+        \ ['^.*\ze\s*%', ''],
+        \]
+
+  let self.re.fold_re = escape(self.open . '|' . self.close, '{}%+*.')
+
+  return self
+endfunction
+
+" }}}1
+function! s:folder.level(line, lnum) abort dict " {{{1
+  if a:line =~# self.re.start
+    let s:self.opened = 1
+    return 'a1'
+  elseif a:line =~# self.re.end
+    let s:self.opened = 0
+    return 's1'
+  endif
+endfunction
+
+" }}}1
+function! s:folder.text(line, level) abort dict " {{{1
+  for [l:re, l:pre] in self.re.text
+    let l:text = matchstr(a:line, l:re)
+    if !empty(l:text) | return l:pre . l:text | endif
+  endfor
+
+  return '% ' . self.open . ' ' . getline(v:foldstart + 1)
+endfunction
+
+" }}}1
+
+endif

autoload/vimtex/fold/preamble.vim

@@ -0,0 +1,36 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'latex') == -1
+
+" vimtex - LaTeX plugin for Vim
+"
+" Maintainer: Karl Yngve Lervåg
+" Email:      karl.yngve@gmail.com
+"
+
+function! vimtex#fold#preamble#new(config) abort " {{{1
+  return extend(deepcopy(s:folder), a:config)
+endfunction
+
+" }}}1
+
+
+let s:folder = {
+      \ 'name' : 'preamble',
+      \ 're' : {
+      \   'start' : '^\s*\\documentclass',
+      \   'fold_re' : '\\documentclass',
+      \ },
+      \}
+function! s:folder.level(line, lnum) abort dict " {{{1
+  if a:line =~# self.re.start
+    return '>1'
+  endif
+endfunction
+
+" }}}1
+function! s:folder.text(line, level) abort dict " {{{1
+  return '      Preamble'
+endfunction
+
+" }}}1
+
+endif

autoload/vimtex/fold/sections.vim

@@ -0,0 +1,180 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'latex') == -1
+
+" vimtex - LaTeX plugin for Vim
+"
+" Maintainer: Karl Yngve Lervåg
+" Email:      karl.yngve@gmail.com
+"
+
+function! vimtex#fold#sections#new(config) abort " {{{1
+  return extend(deepcopy(s:folder), a:config).init()
+endfunction
+
+" }}}1
+
+
+let s:folder = {
+      \ 'name' : 'sections',
+      \ 'parse_levels' : 0,
+      \ 're' : {},
+      \ 'folds' : [],
+      \ 'sections' : [],
+      \ 'parts' : [],
+      \ 'time' : 0,
+      \}
+function! s:folder.init() abort dict " {{{1
+  let self.re.parts = '\v^\s*\\%(' . join(self.parts, '|') . ')'
+  let self.re.sections = '\v^\s*\\%(' . join(self.sections, '|') . ')'
+  let self.re.fake_sections = '\v^\s*\% Fake%('
+        \ . join(self.sections, '|') . ').*'
+  let self.re.any_sections = '\v^\s*%(\\|\% Fake)%('
+        \ . join(self.sections, '|') . ').*'
+
+  let self.re.start = self.re.parts
+        \ . '|' . self.re.sections
+        \ . '|' . self.re.fake_sections
+
+  let self.re.secpat1 = self.re.sections . '\*?\s*\{\zs.*'
+  let self.re.secpat2 = self.re.sections . '\*?\s*\[\zs.*'
+
+  let self.re.fold_re = '\\%(' . join(self.parts + self.sections, '|') . ')'
+
+  return self
+endfunction
+
+" }}}1
+function! s:folder.level(line, lnum) abort dict " {{{1
+  call self.refresh()
+
+  " Fold chapters and sections
+  for [l:part, l:level] in self.folds
+    if a:line =~# l:part
+      return '>' . l:level
+    endif
+  endfor
+endfunction
+
+" }}}1
+function! s:folder.text(line, level) abort dict " {{{1
+  if a:line =~# '\\frontmatter'
+    let l:title = 'Frontmatter'
+  elseif a:line =~# '\\mainmatter'
+    let l:title = 'Mainmatter'
+  elseif a:line =~# '\\backmatter'
+    let l:title = 'Backmatter'
+  elseif a:line =~# '\\appendix'
+    let l:title = 'Appendix'
+  elseif a:line =~# self.re.secpat1
+    let l:title = self.parse_title(matchstr(a:line, self.re.secpat1), 0)
+  elseif a:line =~# self.re.secpat2
+    let l:title = self.parse_title(matchstr(a:line, self.re.secpat2), 1)
+  elseif a:line =~# self.re.fake_sections
+    let l:title = matchstr(a:line, self.re.fake_sections)
+  endif
+
+  let l:level = self.parse_level(v:foldstart, a:level)
+
+  return printf('%-5s %-s', l:level,
+        \ substitute(strpart(l:title, 0, winwidth(0) - 7), '\s\+$', '', ''))
+endfunction
+
+" }}}1
+function! s:folder.parse_level(lnum, level) abort dict " {{{1
+  if !self.parse_levels | return a:level | endif
+
+  if !has_key(self, 'toc')
+    let self.toc = vimtex#toc#new({
+        \ 'name' : 'Fold text ToC',
+        \ 'layers' : ['content'],
+        \ 'refresh_always' : 0,
+        \})
+    let self.toc_updated = 0
+    let self.file_updated = {}
+  endif
+
+  let l:file = expand('%')
+  let l:ftime = getftime(l:file)
+
+  if l:ftime > get(self.file_updated, l:file)
+        \ || localtime() > self.toc_updated + 300
+    call self.toc.get_entries(1)
+    let self.toc_entries = filter(
+          \ self.toc.get_visible_entries(),
+          \ '!empty(v:val.number)')
+    let self.file_updated[l:file] = l:ftime
+    let self.toc_updated = localtime()
+  endif
+
+  let l:entries = filter(deepcopy(self.toc_entries), 'v:val.line == a:lnum')
+  if len(l:entries) > 1
+    call filter(l:entries, "v:val.file ==# expand('%:p')")
+  endif
+
+  return empty(l:entries) ? '' : self.toc.print_number(l:entries[0].number)
+endfunction
+
+" }}}1
+function! s:folder.parse_title(string, type) abort dict " {{{1
+  let l:idx = -1
+  let l:length = strlen(a:string)
+  let l:level = 1
+  while l:level >= 1
+    let l:idx += 1
+    if l:idx > l:length
+      break
+    elseif a:string[l:idx] ==# ['}',']'][a:type]
+      let l:level -= 1
+    elseif a:string[l:idx] ==# ['{','['][a:type]
+      let l:level += 1
+    endif
+  endwhile
+  let l:parsed = strpart(a:string, 0, l:idx)
+  return empty(l:parsed)
+        \ ? '<untitled>' : l:parsed
+endfunction
+
+" }}}1
+function! s:folder.refresh() abort dict " {{{1
+  "
+  " Parse current buffer to find which sections to fold and their levels.  The
+  " patterns are predefined to optimize the folding.
+  "
+  " We ignore top level parts such as \frontmatter, \appendix, \part, and
+  " similar, unless there are at least two such commands in a document.
+  "
+
+  " Only refresh if file has been changed
+  let l:time = getftime(expand('%'))
+  if l:time == self.time | return | endif
+  let self.time = l:time
+
+  " Initialize
+  let self.folds = []
+  let level = 0
+  let buffer = getline(1,'$')
+
+  " Parse part commands (frontmatter, appendix, etc)
+  " Note: We want a minimum of two top level parts
+  let lines = filter(copy(buffer), 'v:val =~ ''' . self.re.parts . '''')
+  if len(lines) >= 2
+    let level += 1
+    call insert(self.folds, [self.re.parts, level])
+  endif
+
+  " Parse section commands (part, chapter, [sub...]section)
+  let lines = filter(copy(buffer), 'v:val =~ ''' . self.re.any_sections . '''')
+  for part in self.sections
+    let partpattern = '^\s*\%(\\\|% Fake\)' . part . ':\?\>'
+    for line in lines
+      if line =~# partpattern
+        let level += 1
+        call insert(self.folds, [partpattern, level])
+        break
+      endif
+    endfor
+  endfor
+endfunction
+
+" }}}1
+
+endif