Capture error codes for yamlllint

ale_linters/yaml/yamllint.vim

@@ -20,21 +20,25 @@ function! ale_linters#yaml#yamllint#Handle(buffer, lines) abort
     " Matches patterns line the following:
     " something.yaml:1:1: [warning] missing document start "---" (document-start)
     " something.yml:2:1: [error] syntax error: expected the node content, but found '<stream end>'
-    let l:pattern = '^.*:\(\d\+\):\(\d\+\): \[\(error\|warning\)\] \(.\+\)$'
+    let l:pattern = '\v^.*:(\d+):(\d+): \[(error|warning)\] (.+)$'
     let l:output = []
 
     for l:match in ale#util#GetMatches(a:lines, l:pattern)
-        let l:line = l:match[1] + 0
-        let l:col = l:match[2] + 0
-        let l:type = l:match[3]
-        let l:text = l:match[4]
+        let l:item = {
+        \   'lnum': l:match[1] + 0,
+        \   'col': l:match[2] + 0,
+        \   'text': l:match[4],
+        \   'type': l:match[3] is# 'error' ? 'E' : 'W',
+        \}
 
-        call add(l:output, {
-        \   'lnum': l:line,
-        \   'col': l:col,
-        \   'text': l:text,
-        \   'type': l:type is# 'error' ? 'E' : 'W',
-        \})
+        let l:code_match = matchlist(l:item.text, '\v^(.+) \(([^)]+)\)$')
+
+        if !empty(l:code_match)
+            let l:item.text = l:code_match[1]
+            let l:item.code = l:code_match[2]
+        endif
+
+        call add(l:output, l:item)
     endfor
 
     return l:output

test/handler/test_yamllint_handler.vader

@@ -11,7 +11,8 @@ Execute:
   \     'lnum': 1,
   \     'col': 1,
   \     'type': 'W',
-  \     'text': 'missing document start "---" (document-start)',
+  \     'text': 'missing document start "---"',
+  \     'code': 'document-start',
   \   },
   \   {
   \     'lnum': 2,