Add markdown syntax support for indented code blocks.

doc/vimwiki.txt

@@ -3486,6 +3486,7 @@ https://github.com/vimwiki-backup/vimwiki/issues.
 2.5 (in progress)~
 
 New:~
+    * Add support for markdown indented code blocks.
     * Issue #764: fenced code blocks are properly supported for markdown
       syntax i.e. more than 3 backticks, adds tilde support.
     * Set default |vimwiki-option-list_margin| = 0 for markdown syntax.

syntax/vimwiki_markdown.vim

@@ -79,9 +79,10 @@ let s:markdown_syntax.number_types = ['1.']
 let s:markdown_syntax.list_markers = ['-', '*', '+', '1.']
 let s:markdown_syntax.rxListDefine = '::\%(\s\|$\)'
 
-" Preformatted text
+" Preformatted text (code blocks)
 let s:markdown_syntax.rxPreStart = '\%(`\{3,}\|\~\{3,}\)'
 let s:markdown_syntax.rxPreEnd = '\%(`\{3,}\|\~\{3,}\)'
+let s:markdown_syntax.rxIndentedCodeBlock = '^\s*\n\(\(\s\{4,}[^ ]\|\t\+[^\t]\).*\n\)\+\(^\s*\n\)'
 
 " Math block
 let s:markdown_syntax.rxMathStart = '\$\$'

syntax/vimwiki_markdown_custom.vim

@@ -190,7 +190,9 @@ syntax match VimwikiTableRow /^\s*|.\+|\s*$/
                            \ VimwikiEqInT,
                            \ @Spell
 
-
+" indented code blocks https://github.github.com/gfm/#indented-code-blocks
+execute 'syntax match VimwikiIndentedCodeBlock /' . vimwiki#vars#get_syntaxlocal('rxIndentedCodeBlock') . '/'
+hi def link VimwikiIndentedCodeBlock VimwikiPre
 
 " syntax group highlighting
 hi def link VimwikiImage VimwikiLink

test/syntax.vader

@@ -226,6 +226,23 @@ Given vimwiki (Markdown, Text and Vim):
   set hlsearch
   ~~~~~~~~~~~
 
+  Here is an indented code block:
+
+      int main()
+
+  Must be surrounded by blank lines.
+
+  This isn't a code block:
+      int main()
+  - But this is one in a list
+  - Item
+    - subitem
+
+        int main()
+
+    - list item
+  - done
+
 Execute (Set syntax markdown):
   let g:vimwiki_global_vars['vimwiki_automatic_nested_syntaxes'] = 1
   call SetSyntax('markdown')
@@ -252,6 +269,9 @@ Execute (Assert Code syntax):
   AssertEqual SyntaxAt(24, 1), 'vimLineComment'
   AssertEqual SyntaxAt(25, 1), 'vimCommand'
   AssertEqual SyntaxAt(26, 1), 'VimwikiPre'
+  AssertEqual SyntaxAt(30, 1), 'VimwikiIndentedCodeBlock'
+  AssertEqual SyntaxAt(35, 1), ''
+  AssertEqual SyntaxAt(40, 1), 'VimwikiIndentedCodeBlock'
 
 
 # 11 Math {{{1