enh(cpp) Improve function declaration detection

CHANGES.md

@@ -19,6 +19,10 @@ Language Improvements:
 - (ini) support TOML arrays, clean up grammar (#2335) [Josh Goebel][]
 - (vbnet) add nameof operator to the keywords (#2329) [Youssef Victor][]
 - (stan) updated with improved coverage of language keywords and patterns. (#1829) [Jeffrey Arnold][]
+- enh(cpp) Detect namespaced function types (`A::typeName func(...)`) (#2332) [Josh Goebel][]
+- enh(cpp) Detect namespaced functions also (`A::functionName`) (#2332) [Josh Goebel][]
+- enh(cpp) Properly detect decltype(auto) (#2332) [Josh Goebel][]
+- enh(cpp) recognize primitive types (`int8_t`, etc.) as function types (#2332) [Josh Goebel][]
 
 Developer Tools:
 

src/languages/cpp.js

@@ -7,6 +7,16 @@ Website: https://isocpp.org
 */
 
 function(hljs) {
+  function optional(s) {
+    return '(?:' + s + ')?';
+  }
+  var DECLTYPE_AUTO_RE = 'decltype\\(auto\\)'
+  var NAMESPACE_RE = '[a-zA-Z_]\\w*::'
+  var TEMPLATE_ARGUMENT_RE = '<.*?>';
+  var FUNCTION_TYPE_RE = '(' +
+    DECLTYPE_AUTO_RE + '|' +
+    optional(NAMESPACE_RE) +'[a-zA-Z_]\\w*' + optional(TEMPLATE_ARGUMENT_RE) +
+  ')';
   var CPP_PRIMITIVE_TYPES = {
     className: 'keyword',
     begin: '\\b[a-z\\d_]*_t\\b'
@@ -64,7 +74,13 @@ function(hljs) {
     ]
   };
 
-  var FUNCTION_TITLE = hljs.IDENT_RE + '\\s*\\(';
+  var TITLE_MODE = {
+    className: 'title',
+    begin: optional(NAMESPACE_RE) + hljs.IDENT_RE,
+    relevance: 0
+  };
+
+  var FUNCTION_TITLE = optional(NAMESPACE_RE) + hljs.IDENT_RE + '\\s*\\(';
 
   var CPP_KEYWORDS = {
     keyword: 'int float while private char char8_t char16_t char32_t catch import module export virtual operator sizeof ' +
@@ -99,86 +115,99 @@ function(hljs) {
     STRINGS
   ];
 
-  return {
-    aliases: ['c', 'cc', 'h', 'c++', 'h++', 'hpp', 'hh', 'hxx', 'cxx'],
+  var EXPRESSION_CONTEXT = {
+    // This mode covers expression context where we can't expect a function
+    // definition and shouldn't highlight anything that looks like one:
+    // `return some()`, `else if()`, `(x*sum(1, 2))`
+    variants: [
+      {begin: /=/, end: /;/},
+      {begin: /\(/, end: /\)/},
+      {beginKeywords: 'new throw return else', end: /;/}
+    ],
     keywords: CPP_KEYWORDS,
-    illegal: '</',
     contains: EXPRESSION_CONTAINS.concat([
-      PREPROCESSOR,
       {
-        begin: '\\b(deque|list|queue|stack|vector|map|set|bitset|multiset|multimap|unordered_map|unordered_set|unordered_multiset|unordered_multimap|array)\\s*<', end: '>',
+        begin: /\(/, end: /\)/,
         keywords: CPP_KEYWORDS,
-        contains: ['self', CPP_PRIMITIVE_TYPES]
-      },
-      {
-        begin: hljs.IDENT_RE + '::',
-        keywords: CPP_KEYWORDS
+        contains: EXPRESSION_CONTAINS.concat(['self']),
+        relevance: 0
+      }
+    ]),
+    relevance: 0
+  };
+
+  var FUNCTION_DECLARATION = {
+    className: 'function',
+    begin: '(' + FUNCTION_TYPE_RE + '[\\*&\\s]+)+' + FUNCTION_TITLE,
+    returnBegin: true, end: /[{;=]/,
+    excludeEnd: true,
+    keywords: CPP_KEYWORDS,
+    illegal: /[^\w\s\*&:<>]/,
+    contains: [
+
+      { // to prevent it from being confused as the function title
+        begin: DECLTYPE_AUTO_RE,
+        keywords: CPP_KEYWORDS,
+        relevance: 0,
       },
       {
-        // This mode covers expression context where we can't expect a function
-        // definition and shouldn't highlight anything that looks like one:
-        // `return some()`, `else if()`, `(x*sum(1, 2))`
-        variants: [
-          {begin: /=/, end: /;/},
-          {begin: /\(/, end: /\)/},
-          {beginKeywords: 'new throw return else', end: /;/}
-        ],
-        keywords: CPP_KEYWORDS,
-        contains: EXPRESSION_CONTAINS.concat([
-          {
-            begin: /\(/, end: /\)/,
-            keywords: CPP_KEYWORDS,
-            contains: EXPRESSION_CONTAINS.concat(['self']),
-            relevance: 0
-          }
-        ]),
+        begin: FUNCTION_TITLE, returnBegin: true,
+        contains: [TITLE_MODE],
         relevance: 0
       },
       {
-        className: 'function',
-        begin: '(' + hljs.IDENT_RE + '[\\*&\\s]+)+' + FUNCTION_TITLE,
-        returnBegin: true, end: /[{;=]/,
-        excludeEnd: true,
+        className: 'params',
+        begin: /\(/, end: /\)/,
         keywords: CPP_KEYWORDS,
-        illegal: /[^\w\s\*&]/,
+        relevance: 0,
         contains: [
+          hljs.C_LINE_COMMENT_MODE,
+          hljs.C_BLOCK_COMMENT_MODE,
+          STRINGS,
+          NUMBERS,
+          CPP_PRIMITIVE_TYPES,
+          // Count matching parentheses.
           {
-            begin: FUNCTION_TITLE, returnBegin: true,
-            contains: [hljs.TITLE_MODE],
-            relevance: 0
-          },
-          {
-            className: 'params',
             begin: /\(/, end: /\)/,
             keywords: CPP_KEYWORDS,
             relevance: 0,
             contains: [
+              'self',
               hljs.C_LINE_COMMENT_MODE,
               hljs.C_BLOCK_COMMENT_MODE,
               STRINGS,
               NUMBERS,
-              CPP_PRIMITIVE_TYPES,
-              // Count matching parentheses.
-              {
-                begin: /\(/, end: /\)/,
-                keywords: CPP_KEYWORDS,
-                relevance: 0,
-                contains: [
-                  'self',
-                  hljs.C_LINE_COMMENT_MODE,
-                  hljs.C_BLOCK_COMMENT_MODE,
-                  STRINGS,
-                  NUMBERS,
-                  CPP_PRIMITIVE_TYPES
-                ]
-              }
+              CPP_PRIMITIVE_TYPES
             ]
-          },
-          hljs.C_LINE_COMMENT_MODE,
-          hljs.C_BLOCK_COMMENT_MODE,
-          PREPROCESSOR
+          }
         ]
       },
+      CPP_PRIMITIVE_TYPES,
+      hljs.C_LINE_COMMENT_MODE,
+      hljs.C_BLOCK_COMMENT_MODE,
+      PREPROCESSOR
+    ]
+  };
+
+  return {
+    aliases: ['c', 'cc', 'h', 'c++', 'h++', 'hpp', 'hh', 'hxx', 'cxx'],
+    keywords: CPP_KEYWORDS,
+    illegal: '</',
+    contains: [].concat(
+      EXPRESSION_CONTEXT,
+      FUNCTION_DECLARATION,
+      EXPRESSION_CONTAINS,
+      [
+      PREPROCESSOR,
+      {
+        begin: '\\b(deque|list|queue|stack|vector|map|set|bitset|multiset|multimap|unordered_map|unordered_set|unordered_multiset|unordered_multimap|array)\\s*<', end: '>',
+        keywords: CPP_KEYWORDS,
+        contains: ['self', CPP_PRIMITIVE_TYPES]
+      },
+      {
+        begin: hljs.IDENT_RE + '::',
+        keywords: CPP_KEYWORDS
+      },
       {
         className: 'class',
         beginKeywords: 'class struct', end: /[{;:]/,

test/markup/cpp/function-declarations.expect.txt

@@ -0,0 +1,16 @@
+<span class="hljs-function"><span class="hljs-keyword">decltype</span>(<span class="hljs-keyword">auto</span>) <span class="hljs-title">look_up_a_string_1</span><span class="hljs-params">()</span> </span>{ <span class="hljs-keyword">return</span> lookup1(); }
+<span class="hljs-function"><span class="hljs-keyword">void</span> <span class="hljs-title">look_up_a_string_2</span><span class="hljs-params">()</span> </span>{ <span class="hljs-keyword">return</span> lookup2(); }
+<span class="hljs-function"><span class="hljs-keyword">friend</span> <span class="hljs-keyword">void</span> <span class="hljs-title">A::showB</span><span class="hljs-params">(B x)</span> </span>{}
+<span class="hljs-function"><span class="hljs-keyword">friend</span> <span class="hljs-keyword">void</span> <span class="hljs-title">showB</span><span class="hljs-params">(B x)</span> </span>{}
+<span class="hljs-function"><span class="hljs-keyword">friend</span> <span class="hljs-keyword">void</span> <span class="hljs-title">showB</span><span class="hljs-params">(B::SomeType x)</span> </span>{}
+<span class="hljs-function"><span class="hljs-keyword">inline</span> <span class="hljs-keyword">int</span> <span class="hljs-title">add</span><span class="hljs-params">(<span class="hljs-keyword">int</span> a, <span class="hljs-keyword">int</span> b)</span> </span>{}
+<span class="hljs-function">int8t <span class="hljs-title">Get_Tile_Value</span><span class="hljs-params">()</span> </span>{}
+
+<span class="hljs-function"><span class="hljs-keyword">int8_t</span> <span class="hljs-title">Get_Tile_Value</span><span class="hljs-params">()</span> </span>{}
+
+<span class="hljs-function">B::type <span class="hljs-title">test</span><span class="hljs-params">()</span> </span>{};
+
+<span class="hljs-comment">// template</span>
+<span class="hljs-function">boost::optional&lt;application&gt; <span class="hljs-title">handle_key</span><span class="hljs-params">(application state, key_code key, coord size)</span></span>;
+
+test();

test/markup/cpp/function-declarations.txt

@@ -0,0 +1,16 @@
+decltype(auto) look_up_a_string_1() { return lookup1(); }
+void look_up_a_string_2() { return lookup2(); }
+friend void A::showB(B x) {}
+friend void showB(B x) {}
+friend void showB(B::SomeType x) {}
+inline int add(int a, int b) {}
+int8t Get_Tile_Value() {}
+
+int8_t Get_Tile_Value() {}
+
+B::type test() {};
+
+// template
+boost::optional<application> handle_key(application state, key_code key, coord size);
+
+test();