fix(ruby) Heredoc without interpolation

CHANGES.md

@@ -53,6 +53,8 @@ Parser:
 
 Grammars:
 
+- enh(crystal) highlight variables (#3154) [Josh Goebel][]
+- fix(ruby) Heredoc without interpolation (#3154) [Josh Goebel][]
 - enh(swift) add `@resultBuilder` attribute (#3151) [Bradley Mackey][]
 - enh(processing) added `pde` alias (#3142) [Dylan McBean][]
 - enh(thrift) Use proper scope for types [Josh Goebel][]

src/languages/crystal.js

@@ -26,6 +26,13 @@ export default function(hljs) {
     end: /\}/,
     keywords: CRYSTAL_KEYWORDS
   };
+  // borrowed from Ruby
+  const VARIABLE = {
+    // negative-look forward attemps to prevent false matches like:
+    // @ident@ or $ident$ that might indicate this is not ruby at all
+    className: "variable",
+    begin: '(\\$\\W)|((\\$|@@?)(\\w+))(?=[^@$?])' + `(?![A-Za-z])(?![@$?'])`
+  };
   const EXPANSION = {
     className: 'template-variable',
     variants: [
@@ -211,6 +218,7 @@ export default function(hljs) {
     REGEXP2,
     REGEXP,
     ATTRIBUTE,
+    VARIABLE,
     hljs.HASH_COMMENT_MODE,
     {
       className: 'class',

src/languages/ruby.js

@@ -124,13 +124,15 @@ export default function(hljs) {
       {
         begin: /\B\?\\?\S/
       },
-      { // heredocs
-        begin: /<<[-~]?'?(\w+)\n(?:[^\n]*\n)*?\s*\1\b/,
-        returnBegin: true,
+      // heredocs
+      {
+        // this guard makes sure that we have an entire heredoc and not a false
+        // positive (auto-detect, etc.)
+        begin: regex.concat(
+          /<<[-~]?'?/,
+          regex.lookahead(/(\w+)(?=\W)[^\n]*\n(?:[^\n]*\n)*?\s*\1\b/)
+        ),
         contains: [
-          {
-            begin: /<<[-~]?'?/
-          },
           hljs.END_SAME_AS_BEGIN({
             begin: /(\w+)/,
             end: /(\w+)/,

test/markup/ruby/heredoc.expect.txt

@@ -1,3 +1,18 @@
+<span class="hljs-comment"># standard heredoc</span>
+message = <span class="hljs-string">&lt;&lt;-MESSAGE
+  This looks good
+MESSAGE</span>
+
+<span class="hljs-comment"># heredoc without interpolation</span>
+message = <span class="hljs-string">&lt;&lt;-&#x27;MESSAGE&#x27;
+  This isn&#x27;t highlighted correctly
+MESSAGE</span>
+
+<span class="hljs-comment"># with a method call</span>
+message = <span class="hljs-string">&lt;&lt;-MESSAGE.chomp
+  This looks good
+MESSAGE</span>
+
 <span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">foo</span><span class="hljs-params">()</span></span>
   msg = <span class="hljs-string">&lt;&lt;-HTML
   &lt;div&gt;
@@ -12,4 +27,5 @@
     &lt;h4&gt;<span class="hljs-subst">#{bar}</span>&lt;/h4&gt;
   &lt;/div&gt;
   FOO</span>
-<span class="hljs-keyword">end</span>
+<span class="hljs-keyword">end</span>
+

test/markup/ruby/heredoc.txt

@@ -1,3 +1,18 @@
+# standard heredoc
+message = <<-MESSAGE
+  This looks good
+MESSAGE
+
+# heredoc without interpolation
+message = <<-'MESSAGE'
+  This isn't highlighted correctly
+MESSAGE
+
+# with a method call
+message = <<-MESSAGE.chomp
+  This looks good
+MESSAGE
+
 def foo()
   msg = <<-HTML
   <div>
@@ -12,4 +27,5 @@ def baz()
     <h4>#{bar}</h4>
   </div>
   FOO
-end
+end
+