Syntax: Add highlithing for YAML metadata block (#1287)

autoload/vimwiki/vars.vim

@@ -673,6 +673,7 @@ endfunction
 function! s:get_default_syntaxlocal() abort
   " Get default syntaxlocal variable dictionary
   " type, default, min, max, possible_values, min_length
+
   return extend(s:get_common_syntaxlocal(), {
         \ 'bold_match': {'type': type(''), 'default': '\%(^\|\s\|[[:punct:]]\)\@<=\*__Text__\*\%([[:punct:]]\|\s\|$\)\@='},
         \ 'bold_search': {'type': type(''), 'default': '\%(^\|\s\|[[:punct:]]\)\@<=\*\zs\%([^*`[:space:]][^*`]*[^*`[:space:]]\|[^*`[:space:]]\)\ze\*\%([[:punct:]]\|\s\|$\)\@='},
@@ -815,10 +816,23 @@ endfunction
 
 function! s:get_common_syntaxlocal() abort
   let res = {}
+
+  " Declare helper: a line with only --- or ...
+  let rx_yaml_start_pre = '\%(^\%(\%1l\|^$\n\)\@<=\)'
+  let rx_yaml_start_post = '\%(\%(\n^$\)\@!$\)'
+  let a_yaml_region = []
+  for rx_yaml_delimiter in ['---', '\.\.\.']
+    let rx_yaml_start = rx_yaml_start_pre . rx_yaml_delimiter . rx_yaml_start_post
+    let rx_yaml_stop = '^' . rx_yaml_delimiter . '$'
+    call add(a_yaml_region, [rx_yaml_start, rx_yaml_stop])
+  endfor
+
   let res.nested_extended = {'type': type(''), 'default': 'VimwikiError,VimwikiPre,VimwikiCode,VimwikiEqIn,VimwikiSuperScript,VimwikiSubScript,textSnipTEX'}
   let res.nested_typeface = {'type': type(''), 'default': 'VimwikiBold,VimwikiItalic,VimwikiUnderline,VimwikiDelText'}
   let res.nested = {'type': type(''), 'default': res.nested_extended.default . ',' . res.nested_typeface.default}
   let res.rxTableSep = {'type': type(''), 'default': '|'}
+  " See issue #1287
+  let res.yaml_metadata_block = {'type': type([]), 'default': a_yaml_region}
   return res
 endfunction
 

doc/vimwiki.txt

@@ -2938,7 +2938,9 @@ color. (See autoload/vimwiki/vars.vim)
 
 Syntax options are configured using the following pattern: >
 
-    let g:vimwiki_syntax_list['markdown']['bullet_type'] = ['*', '-', '+']
+    let g:vimwiki_syntaxlocal_vars = {}
+    let g:vimwiki_syntaxlocal_vars['markdown'] = []
+    let g:vimwiki_syntaxlocal_vars['markdown']['bullet_type'] = ['*', '-', '+']
 
 Where:
 - `markdown` is the syntax name. It can be (`default`, `markdown` or `media`)
@@ -2946,6 +2948,16 @@ Where:
 - `['*', '-', '+']` is the option value
 
 
+------------------------------------------------------------------------------
+*yaml_metadata_block*
+
+List of (start, end) regex region delimiters to define the YAML header
+More information in #1287 and https://pandoc.org/MANUAL.html#extension-yaml_metadata_block
+
+Default: [['^---$', '^---$'], ['^\.\.\.$', '^\.\.\.$']]
+or similar with stricter anchors
+
+
 ------------------------------------------------------------------------------
 12.5 Global Options                                   *vimwiki-global-options*
 
@@ -3999,6 +4011,11 @@ master is retained as a legacy mirror of the dev branch.
 
 This is somewhat experimental, and will probably be refined over time.
 
+New:~
+    * Issue #1287 Highlight YAML header with |yaml_metadata_block|
+      configuration variable holding region delimiters
+
+
 2022.12.02~
 
 New:~

syntax/vimwiki.vim

@@ -508,6 +508,17 @@ if !empty(s:nested)
   endfor
 endif
 
+" Include: Yaml metadata block for pandoc
+let a_yaml_delimiter = vimwiki#vars#get_syntaxlocal('yaml_metadata_block')
+for [rx_start, rx_end] in a_yaml_delimiter
+  call vimwiki#base#nested_syntax(
+        \ 'yaml',
+        \ rx_start,
+        \ rx_end,
+        \ 'VimwikiPre')
+endfor
+
+
 " LaTex: Load
 if !empty(globpath(&runtimepath, 'syntax/tex.vim'))
   execute 'syntax include @textGrouptex syntax/tex.vim'

test/issue_1287_yaml_header.vader

@@ -0,0 +1,95 @@
+# Non regression tests for issue: #1287
+
+
+Before(Define function for yaml inspection):
+  function! Issue1287Yaml(line)
+    " The line where the yaml delimiter is: 1 if at top
+    let l = a:line
+    AssertEqual 'textSnipYAML', GetSyntaxStack(l + 0, 2)[0]
+    AssertEqual 'VimwikiPre', GetSyntaxStack(l + 0, 2)[1]
+
+    AssertEqual 'textSnipYAML', GetSyntaxStack(l + 1, 2)[0]
+    AssertEqual 'textSnipYAML', GetSyntaxStack(l + 2, 2)[0]
+    AssertEqual 'textSnipYAML', GetSyntaxStack(l + 2, 20)[0]
+
+    AssertEqual 'VimwikiPre', GetSyntaxStack(l + 3, 2)[-1]
+  endfunction
+
+
+Given vimwiki (Yaml with --- at top):
+  ---
+  title: my title
+  description: my description
+  ---
+
+Execute (Assert delimiter with --- at top):
+  call Issue1287Yaml(1)
+
+Given vimwiki (Yaml with ... at top):
+  ...
+  title: my title
+  description: my description
+  ...
+
+Execute (Assert delimiter with ... at top):
+  call Issue1287Yaml(1)
+
+Given vimwiki (Yaml with --- after empty line):
+  A stupid block
+  of 2 lines
+  
+  ---
+  title: my title
+  description: my description
+  ---
+
+Execute (Assert delimiter with --- after empty line):
+  call Issue1287Yaml(4)
+
+
+Given vimwiki (Yaml with --- mixed with ...):
+  ---
+  title: my title
+  ...
+  comment: my comment
+  description: my description
+  ---
+  
+  And a text follows
+
+Execute (Assert all is yaml except after the closing ---):
+  AssertEqual 'textSnipYAML1', GetSyntaxStack(1, 2)[0] . 1
+  AssertEqual 'VimwikiPre1', GetSyntaxStack(1, 2)[1] . 1
+
+  AssertEqual 'textSnipYAML1', GetSyntaxStack(1, 2)[0] . 1
+  AssertEqual 'textSnipYAML2', GetSyntaxStack(2, 2)[0] . 2
+  AssertEqual 'textSnipYAML3', GetSyntaxStack(3, 2)[0] . 3
+  AssertEqual 'textSnipYAML4', GetSyntaxStack(4, 2)[0] . 4
+  AssertEqual 'textSnipYAML5', GetSyntaxStack(5, 2)[0] . 5
+  AssertEqual 'textSnipYAML6', GetSyntaxStack(5, 2)[0] . 6
+
+  AssertEqual 0, len(GetSyntaxStack(7, 2))
+  AssertEqual 0, len(GetSyntaxStack(8, 2))
+
+
+Given vimwiki (Yaml with --- with a --- not a start of line):
+  ---
+  title: my title
+  comment: my comment ---
+  description: my description
+  ---
+  
+  And a text follows
+
+Execute (Assert all is yaml except after the closing ---):
+  AssertEqual 'textSnipYAML1', GetSyntaxStack(1, 2)[0] . 1
+  AssertEqual 'VimwikiPre1', GetSyntaxStack(1, 2)[1] . 1
+
+  AssertEqual 'textSnipYAML1', GetSyntaxStack(1, 2)[0] . 1
+  AssertEqual 'textSnipYAML2', GetSyntaxStack(2, 2)[0] . 2
+  AssertEqual 'textSnipYAML3', GetSyntaxStack(3, 2)[0] . 3
+  AssertEqual 'textSnipYAML4', GetSyntaxStack(4, 2)[0] . 4
+  AssertEqual 'VimwikiPre5', GetSyntaxStack(5, 2)[-1] . 5
+
+  AssertEqual 0, len(GetSyntaxStack(6, 2))
+  AssertEqual 0, len(GetSyntaxStack(7, 2))

test/vimrc

@@ -343,21 +343,37 @@
     0d
   endfunction
 
-  function! GetSyntaxGroup(line, col)
+  function! GetSyntaxGroup(...)
     " Get normalized syntax group: usefull for boldItalic Vs italicBold
+    " Arg1: line
+    " Arg2: column
     " -- Here, Vader's SyntaxAt is not enough
     " From: https://stackoverflow.com/questions/9464844
-    let l:s = synID(a:line, a:col, 1)
+    let line = a:0 >= 1 ? a:1 : '.'
+    let col = a:0 >= 2 ? a:2 : '.'
+
+    let l:s = synID(line, col, 1)
     return synIDattr(synIDtrans(l:s), 'name')
   endfun
 
-  function! GetSyntaxStack()
+  function! GetSyntaxStack(...)
     " Debug helper
+    " Arg1: line
+    " Arg2: column
+    let line = a:0 >= 1 ? a:1 : '.'
+    let col = a:0 >= 2 ? a:2 : '.'
     if !exists('*synstack')
-      return
+      return []
     endif
-    return map(synstack(line('.'), col('.')), 'synIDattr(v:val, "name")')
+    let res = map(synstack(line, col), 'synIDattr(v:val, "name")')
-  endfunc
+
+    " For old vim version returning 0
+    if type(res) == type(0) && res == 0
+      return []
+    endif
+
+    return res
+  endfunction
 
   function! AssertIfVersion(version, one, two)
     " Run Assert only if vim version is high enough