fix(yaml) - correct escaping behavior in single-quoted YAML strings (#4159)

* add 1char.escape1 scope to escape sequences in single quoted strings

Author: guuido

CHANGES.md

@@ -39,6 +39,7 @@ Core Grammars:
 - fix(nix) handle backslash string escapes [h7x4][]
 - fix(nix) don't mix escapes for `"` and `''` strings [h7x4][]
 - fix(swift) - Fixed syntax highlighting for class func/var declarations [guuido]
+- fix(yaml) - Fixed wrong escaping behavior in single quoted strings [guuido]
 
 New Grammars:
 

src/languages/yaml.js

@@ -42,14 +42,25 @@ export default function(hljs) {
       }
     ]
   };
+
+  const SINGLE_QUOTE_STRING = {
+    className: 'string',
+    relevance: 0,
+    begin: /'/,
+    end: /'/,
+    contains: [
+      {
+        match: /''/,
+        scope: 'char.escape',
+        relevance: 0
+      }
+    ]
+  };
+
   const STRING = {
     className: 'string',
     relevance: 0,
     variants: [
-      {
-        begin: /'/,
-        end: /'/
-      },
       {
         begin: /"/,
         end: /"/
@@ -67,7 +78,13 @@ export default function(hljs) {
   const CONTAINER_STRING = hljs.inherit(STRING, { variants: [
     {
       begin: /'/,
-      end: /'/
+      end: /'/,
+      contains: [
+        {
+          begin: /''/,
+          relevance: 0
+        }
+      ]
     },
     {
       begin: /"/,
@@ -176,6 +193,7 @@ export default function(hljs) {
     },
     OBJECT,
     ARRAY,
+    SINGLE_QUOTE_STRING,
     STRING
   ];
 

test/markup/yaml/string.expect.txt

@@ -5,3 +5,11 @@
   multi-string
   value
 </span><span class="hljs-attr">key:</span> <span class="hljs-literal">true</span>
+
+<span class="hljs-attr">key:</span> <span class="hljs-string">&#x27;\&#x27;</span>
+<span class="hljs-attr">key:</span> <span class="hljs-string">&quot;\\&quot;</span>
+<span class="hljs-attr">key:</span> <span class="hljs-string">&quot;\&quot;
+key: value&quot;</span>
+<span class="hljs-attr">key:</span> <span class="hljs-string">value</span>
+<span class="hljs-attr">key:</span> <span class="hljs-string">&#x27;<span class="hljs-char escape_">&#x27;&#x27;</span>&#x27;</span>
+<span class="hljs-attr">key:</span> <span class="hljs-string">&#x27;some<span class="hljs-char escape_">&#x27;&#x27;</span>value&#x27;</span>

test/markup/yaml/string.txt

@@ -5,3 +5,11 @@ key: |
   multi-string
   value
 key: true
+
+key: '\'
+key: "\\"
+key: "\"
+key: value"
+key: value
+key: ''''
+key: 'some''value'