1 files changed, 54 insertions, 0 deletions
diff --git a/autoload/RstFold.vim b/autoload/RstFold.vim
new file mode 100644
index 00000000..558fe464
--- /dev/null
+++ b/autoload/RstFold.vim
@@ -0,0 +1,54 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'rst') == -1
+  
+" Author: Antony Lee <anntzer.lee@gmail.com>
+" Description: Helper functions for reStructuredText syntax folding
+" Last Modified: 2018-01-07
+
+function s:CacheRstFold()
+  let closure = {'header_types': {}, 'max_level': 0, 'levels': {}}
+  function closure.Process(match) dict
+    let curline = getcurpos()[1]
+    if has_key(self.levels, curline - 1)
+      " For over+under-lined headers, the regex will match both at the
+      " overline and at the title itself; in that case, skip the second match.
+      return
+    endif
+    let lines = split(a:match, '\n')
+    let key = repeat(lines[-1][0], len(lines))
+    if !has_key(self.header_types, key)
+      let self.max_level += 1
+      let self.header_types[key] = self.max_level
+    endif
+    let self.levels[curline] = self.header_types[key]
+  endfunction
+  let save_cursor = getcurpos()
+  let save_mark = getpos("'[")
+  silent keeppatterns %s/\v^%(%(([=`:.'"~^_*+#-])\1+\n)?.{1,2}\n([=`:.'"~^_*+#-])\2+)|%(%(([=`:.''"~^_*+#-])\3{2,}\n)?.{3,}\n([=`:.''"~^_*+#-])\4{2,})$/\=closure.Process(submatch(0))/gn
+  call setpos('.', save_cursor)
+  call setpos("'[", save_mark)
+  let b:RstFoldCache = closure.levels
+endfunction
+
+function RstFold#GetRstFold()
+  if !has_key(b:, 'RstFoldCache')
+    call s:CacheRstFold()
+  endif
+  if has_key(b:RstFoldCache, v:lnum)
+    return '>' . b:RstFoldCache[v:lnum]
+  else
+    return '='
+  endif
+endfunction
+
+function RstFold#GetRstFoldText()
+  if !has_key(b:, 'RstFoldCache')
+    call s:CacheRstFold()
+  endif
+  let indent = repeat('  ', b:RstFoldCache[v:foldstart] - 1)
+  let thisline = getline(v:foldstart)
+  " For over+under-lined headers, skip the overline.
+  let text = thisline =~ '^\([=`:.''"~^_*+#-]\)\1\+$' ? getline(v:foldstart + 1) : thisline
+  return indent . text
+endfunction
+
+endif