enh(swift) Improved highlighting for types and generic arguments (#2920)

CHANGES.md

@@ -19,6 +19,7 @@ Language improvements:
   - New grammar for attributes
   - Added support for quoted identifiers, implicit parameters, and property wrapper projections
   - Support for more complex expressions in string interpolation
+- enh(swift) Improved highlighting for types and generic arguments (#2920) [Steven Van Impe][]
 - fix(http) avoid recursive sublanguage and tighten rules (#2893) [Josh Goebel][]
 - fix(asciidoc): Handle section titles level 5 (#2868) [Vaibhav Chanana][]
 

src/languages/lib/kws_swift.js

@@ -258,6 +258,9 @@ export const identifierCharacter = either(
 // Valid identifier.
 export const identifier = concat(identifierHead, identifierCharacter, '*');
 
+// Valid type identifier.
+export const typeIdentifier = concat(/[A-Z]/, identifierCharacter, '*');
+
 // Built-in attributes, which are highlighted as keywords.
 // @available is handled separately.
 export const keywordAttributes = [

src/languages/swift.js

@@ -16,6 +16,15 @@ import {
 
 /** @type LanguageFn */
 export default function(hljs) {
+  // https://docs.swift.org/swift-book/ReferenceManual/LexicalStructure.html#ID411
+  const BLOCK_COMMENT = hljs.COMMENT(
+    '/\\*',
+    '\\*/',
+    {
+      contains: [ 'self' ]
+    }
+  );
+
   // https://docs.swift.org/swift-book/ReferenceManual/LexicalStructure.html#ID413
   // https://docs.swift.org/swift-book/ReferenceManual/zzSummaryOfTheGrammar.html
   const DOT_KEYWORD = {
@@ -77,6 +86,11 @@ export default function(hljs) {
   ];
 
   // https://docs.swift.org/swift-book/ReferenceManual/LexicalStructure.html#ID418
+  const OPERATOR_GUARD = {
+    // Prevent -> from being highlighting as an operator.
+    begin: /->/,
+    relevance: 0
+  };
   const OPERATOR = {
     className: 'operator',
     relevance: 0,
@@ -92,6 +106,10 @@ export default function(hljs) {
       }
     ]
   };
+  const OPERATORS = [
+    OPERATOR_GUARD,
+    OPERATOR
+  ];
 
   // https://docs.swift.org/swift-book/ReferenceManual/LexicalStructure.html#grammar_numeric-literal
   // TODO: Update for leading `-` after lookbehind is supported everywhere
@@ -205,7 +223,7 @@ export default function(hljs) {
         .join(' ')
     },
     contains: [
-      OPERATOR,
+      ...OPERATORS,
       NUMBER,
       STRING
     ]
@@ -224,24 +242,46 @@ export default function(hljs) {
     USER_DEFINED_ATTRIBUTE
   ];
 
+  // https://docs.swift.org/swift-book/ReferenceManual/Types.html
   const TYPE = {
-    className: 'type',
-    begin: '\\b[A-Z][\\w\u00C0-\u02B8\']*',
-    relevance: 0
+    begin: lookahead(/\b[A-Z]/),
+    relevance: 0,
+    contains: [
+      { // Common Apple frameworks, for relevance boost
+        className: 'type',
+        begin: concat(/(AV|CA|CF|CG|CI|CL|CM|CN|CT|MK|MP|MTK|MTL|NS|SCN|SK|UI|WK|XC)/, Swift.identifierCharacter, '+')
+      },
+      { // Type identifier
+        className: 'type',
+        begin: Swift.typeIdentifier,
+        relevance: 0
+      },
+      { // Optional type
+        begin: /[?!]+/,
+        relevance: 0
+      },
+      { // Variadic parameter
+        begin: /\.\.\./,
+        relevance: 0
+      },
+      { // Protocol composition
+        begin: concat(/\s+&\s+/, lookahead(Swift.typeIdentifier)),
+        relevance: 0
+      }
+    ]
   };
-  // slightly more special to swift
-  const OPTIONAL_USING_TYPE = {
-    className: 'type',
-    begin: '\\b[A-Z][\\w\u00C0-\u02B8\']*[!?]',
-    relevance: 0
+  const GENERIC_ARGUMENTS = {
+    begin: /</,
+    end: />/,
+    keywords: KEYWORDS,
+    contains: [
+      ...KEYWORD_MODES,
+      ...ATTRIBUTES,
+      OPERATOR_GUARD,
+      TYPE
+    ]
   };
-  const BLOCK_COMMENT = hljs.COMMENT(
-    '/\\*',
-    '\\*/',
-    {
-      contains: [ 'self' ]
-    }
-  );
+  TYPE.contains.push(GENERIC_ARGUMENTS);
 
   // Add supported submodes to string interpolation.
   for (const variant of STRING.variants) {
@@ -251,7 +291,7 @@ export default function(hljs) {
     const submodes = [
       ...KEYWORD_MODES,
       ...BUILT_INS,
-      OPERATOR,
+      ...OPERATORS,
       NUMBER,
       STRING,
       ...IDENTIFIERS
@@ -333,12 +373,11 @@ export default function(hljs) {
       },
       ...KEYWORD_MODES,
       ...BUILT_INS,
-      OPERATOR,
+      ...OPERATORS,
       NUMBER,
       STRING,
       ...IDENTIFIERS,
       ...ATTRIBUTES,
-      OPTIONAL_USING_TYPE,
       TYPE
     ]
   };

test/markup/swift/types.expect.txt

@@ -0,0 +1,43 @@
+<span class="hljs-comment">// Simple identifier</span>
+<span class="hljs-type">Int</span>
+
+<span class="hljs-comment">// Types from Apple frameworks</span>
+<span class="hljs-type">CALayer</span>
+<span class="hljs-type">CGRect</span>
+<span class="hljs-type">MKMapView</span>
+<span class="hljs-type">NSView</span>
+<span class="hljs-type">UIView</span>
+<span class="hljs-type">XCTest</span>
+
+<span class="hljs-comment">// ?, !, ..., and &amp; should not be highlighted as operators</span>
+<span class="hljs-type">Int</span>?
+<span class="hljs-type">Int</span>!
+<span class="hljs-type">Int</span>?!
+<span class="hljs-type">String</span>...
+<span class="hljs-type">SomeClass</span> &amp; <span class="hljs-type">SomeProtocol</span>
+
+<span class="hljs-comment">// Arrays, dictionaries, and nested types</span>
+[<span class="hljs-type">String</span>]
+<span class="hljs-type">Array</span>&lt;<span class="hljs-type">String</span>&gt;
+[[<span class="hljs-type">Int</span>?]]
+<span class="hljs-type">Array</span>&lt;<span class="hljs-type">Array</span>&lt;<span class="hljs-type">Int</span>?&gt;&gt;
+[<span class="hljs-type">String</span>: <span class="hljs-type">Int</span>]
+<span class="hljs-type">Dictionary</span>&lt;<span class="hljs-type">String</span>, <span class="hljs-type">Int</span>&gt;
+<span class="hljs-type">Swift</span>.<span class="hljs-type">Array</span>&lt;<span class="hljs-type">Int</span>&gt;.<span class="hljs-type">Element</span>
+
+<span class="hljs-comment">// Tuples</span>
+()
+(<span class="hljs-type">Double</span>, <span class="hljs-type">Double</span>)
+(x: <span class="hljs-type">Double</span>, y: <span class="hljs-type">Double</span>)
+
+<span class="hljs-comment">// Functions</span>
+(<span class="hljs-keyword">@escaping</span> (<span class="hljs-type">String</span>) -&gt; <span class="hljs-type">Void</span>, <span class="hljs-keyword">@autoclosure</span> () -&gt; <span class="hljs-type">String</span>) -&gt; <span class="hljs-type">String</span>
+(<span class="hljs-type">Int</span>, <span class="hljs-type">String</span>...) -&gt; <span class="hljs-keyword">some</span> <span class="hljs-type">Collection</span>
+() <span class="hljs-keyword">throws</span> -&gt; <span class="hljs-keyword">Self</span>
+
+<span class="hljs-comment">// Generic arguments</span>
+<span class="hljs-type">Array</span>&lt;<span class="hljs-type">String</span>.<span class="hljs-keyword">Type</span>&gt;
+<span class="hljs-type">Array</span>&lt;<span class="hljs-type">Sequence</span>.<span class="hljs-keyword">Protocol</span>&gt;
+<span class="hljs-type">Dictionary</span>&lt;<span class="hljs-type">String</span>, <span class="hljs-keyword">Any</span>&gt;
+<span class="hljs-type">Dictionary</span>&lt;<span class="hljs-type">String</span>, <span class="hljs-type">Array</span>&lt;<span class="hljs-type">Int</span>&gt;&gt;
+<span class="hljs-type">Array</span>&lt;(<span class="hljs-keyword">@autoclosure</span> () -&gt; <span class="hljs-type">String</span>) <span class="hljs-keyword">throws</span> -&gt; <span class="hljs-type">String</span>?&gt;

test/markup/swift/types.txt

@@ -0,0 +1,43 @@
+// Simple identifier
+Int
+
+// Types from Apple frameworks
+CALayer
+CGRect
+MKMapView
+NSView
+UIView
+XCTest
+
+// ?, !, ..., and & should not be highlighted as operators
+Int?
+Int!
+Int?!
+String...
+SomeClass & SomeProtocol
+
+// Arrays, dictionaries, and nested types
+[String]
+Array<String>
+[[Int?]]
+Array<Array<Int?>>
+[String: Int]
+Dictionary<String, Int>
+Swift.Array<Int>.Element
+
+// Tuples
+()
+(Double, Double)
+(x: Double, y: Double)
+
+// Functions
+(@escaping (String) -> Void, @autoclosure () -> String) -> String
+(Int, String...) -> some Collection
+() throws -> Self
+
+// Generic arguments
+Array<String.Type>
+Array<Sequence.Protocol>
+Dictionary<String, Any>
+Dictionary<String, Array<Int>>
+Array<(@autoclosure () -> String) throws -> String?>