Merge 04701225ad into f9f845f28f

ftplugin/markdown.vim

@@ -54,6 +54,18 @@ function! MarkdownFold() abort
     return ">2"
   endif
 
+  " Front matter
+  if v:lnum == 1 && line == '---'
+    let b:markdown_frontmatter = 1
+    return ">1"
+  endif
+
+  " End of front matter
+  if (line == '...') && b:markdown_frontmatter
+    unlet b:markdown_frontmatter
+    return '<1'
+  endif
+
   return "="
 endfunction
 

syntax/markdown.vim

@@ -85,6 +85,10 @@ syn match markdownBlockquote ">\%(\s\|$\)" contained nextgroup=@markdownBlock
 
 syn region markdownCodeBlock start="^\n\( \{4,}\|\t\)" end="^\ze \{,3}\S.*$" keepend
 
+syn include @yamlTop syntax/yaml.vim
+syntax match YAMLFrontMatter /\%^---\_.\{-}\.\.\.$/ contains=@yamlTop
+unlet! b:current_syntax
+
 " TODO: real nesting
 syn match markdownListMarker "\%(\t\| \{0,4\}\)[-*+]\%(\s\+\S\)\@=" contained
 syn match markdownOrderedListMarker "\%(\t\| \{0,4}\)\<\d\+\.\%(\s\+\S\)\@=" contained