[Aliki] Add C syntax highlighting with a custom JS highlighter

lib/rdoc/generator/template/aliki/_head.rhtml

@@ -82,6 +82,7 @@
 <script src="<%= h asset_rel_prefix %>/js/search.js" defer></script>
 <script src="<%= h asset_rel_prefix %>/js/search_index.js" defer></script>
 <script src="<%= h asset_rel_prefix %>/js/searcher.js" defer></script>
+<script src="<%= h asset_rel_prefix %>/js/c_highlighter.js" defer></script>
 <script src="<%= h asset_rel_prefix %>/js/aliki.js" defer></script>
 
 <link href="<%= h asset_rel_prefix %>/css/rdoc.css" rel="stylesheet">

lib/rdoc/generator/template/aliki/class.rhtml

@@ -161,7 +161,7 @@
         <div class="method-description">
           <%- if method.token_stream then %>
           <div class="method-source-code" id="<%= method.html_name %>-source">
-            <pre><%= method.markup_code %></pre>
+            <pre class="<%= method.source_language %>" data-language="<%= method.source_language %>"><%= method.markup_code %></pre>
           </div>
           <%- end %>
           <%- if method.mixin_from then %>

lib/rdoc/generator/template/aliki/css/rdoc.css

@@ -46,6 +46,18 @@
   --code-purple: #7e22ce;
   --code-red: #dc2626;
 
+  /* C syntax highlighting */
+  --c-keyword: #b91c1c;
+  --c-type: #0891b2;
+  --c-macro: #ea580c;
+  --c-function: #7c3aed;
+  --c-identifier: #475569;
+  --c-operator: #059669;
+  --c-preprocessor: #a21caf;
+  --c-value: #92400e;
+  --c-string: #15803d;
+  --c-comment: #78716c;
+
   /* Color Palette - Green (for success states) */
   --color-green-400: #4ade80;
   --color-green-500: #22c55e;
@@ -163,6 +175,18 @@
   --code-purple: #c084fc;
   --code-red: #f87171;
 
+  /* C syntax highlighting */
+  --c-keyword: #f87171;
+  --c-type: #22d3ee;
+  --c-macro: #fb923c;
+  --c-function: #a78bfa;
+  --c-identifier: #94a3b8;
+  --c-operator: #6ee7b7;
+  --c-preprocessor: #e879f9;
+  --c-value: #fcd34d;
+  --c-string: #4ade80;
+  --c-comment: #a8a29e;
+
   /* Semantic Colors - Dark Theme */
   --color-text-primary: var(--color-neutral-50);
   --color-text-secondary: var(--color-neutral-200);
@@ -820,6 +844,22 @@ main h6 a:hover {
 [data-theme="dark"] .ruby-value      { color: var(--code-orange); }
 [data-theme="dark"] .ruby-string     { color: var(--code-green); }
 
+/* C Syntax Highlighting */
+.c-keyword { color: var(--c-keyword); }
+.c-type { color: var(--c-type); }
+.c-macro { color: var(--c-macro); }
+.c-function { color: var(--c-function); }
+.c-identifier { color: var(--c-identifier); }
+.c-operator { color: var(--c-operator); }
+.c-preprocessor { color: var(--c-preprocessor); }
+.c-value { color: var(--c-value); }
+.c-string { color: var(--c-string); }
+
+.c-comment {
+  color: var(--c-comment);
+  font-style: italic;
+}
+
 /* Emphasis */
 em {
   text-decoration-color: var(--color-emphasis-decoration);

lib/rdoc/generator/template/aliki/js/c_highlighter.js

@@ -0,0 +1,299 @@
+/**
+ * Client-side C syntax highlighter for RDoc
+ */
+
+(function() {
+  'use strict';
+
+  // C control flow and storage class keywords
+  const C_KEYWORDS = new Set([
+    'auto', 'break', 'case', 'continue', 'default', 'do', 'else', 'extern',
+    'for', 'goto', 'if', 'inline', 'register', 'return', 'sizeof', 'static',
+    'switch', 'while',
+    '_Alignas', '_Alignof', '_Generic', '_Noreturn', '_Static_assert', '_Thread_local'
+  ]);
+
+  // C type keywords and type qualifiers
+  const C_TYPE_KEYWORDS = new Set([
+    'bool', 'char', 'const', 'double', 'enum', 'float', 'int', 'long',
+    'restrict', 'short', 'signed', 'struct', 'typedef', 'union', 'unsigned',
+    'void', 'volatile', '_Atomic', '_Bool', '_Complex', '_Imaginary'
+  ]);
+
+  // Library-defined types (typedef'd in headers, not language keywords)
+  // Includes: Ruby C API types (VALUE, ID), POSIX types (size_t, ssize_t),
+  // fixed-width integer types (uint32_t, int64_t), and standard I/O types (FILE)
+  const C_TYPES = new Set([
+    'VALUE', 'ID', 'size_t', 'ssize_t', 'ptrdiff_t', 'uintptr_t', 'intptr_t',
+    'uint8_t', 'uint16_t', 'uint32_t', 'uint64_t',
+    'int8_t', 'int16_t', 'int32_t', 'int64_t',
+    'FILE', 'DIR', 'va_list'
+  ]);
+
+  // Common Ruby VALUE macros and boolean literals
+  const RUBY_MACROS = new Set([
+    'Qtrue', 'Qfalse', 'Qnil', 'Qundef', 'NULL', 'TRUE', 'FALSE', 'true', 'false'
+  ]);
+
+  const OPERATORS = new Set([
+    '==', '!=', '<=', '>=', '&&', '||', '<<', '>>', '++', '--',
+    '+=', '-=', '*=', '/=', '%=', '&=', '|=', '^=', '->',
+    '+', '-', '*', '/', '%', '<', '>', '=', '!', '&', '|', '^', '~'
+  ]);
+
+  // Single character that can start an operator
+  const OPERATOR_CHARS = new Set('+-*/%<>=!&|^~');
+
+  function isMacro(word) {
+    return RUBY_MACROS.has(word) || /^[A-Z][A-Z0-9_]*$/.test(word);
+  }
+
+  function isType(word) {
+    return C_TYPE_KEYWORDS.has(word) || C_TYPES.has(word) || /_t$/.test(word);
+  }
+
+  /**
+   * Escape HTML special characters
+   */
+  function escapeHtml(text) {
+    return text
+      .replace(/&/g, '&amp;')
+      .replace(/</g, '&lt;')
+      .replace(/>/g, '&gt;')
+      .replace(/"/g, '&quot;')
+      .replace(/'/g, '&#39;');
+  }
+
+  /**
+   * Check if position is at line start (only whitespace before it)
+   */
+  function isLineStart(code, pos) {
+    if (pos === 0) return true;
+    for (let i = pos - 1; i >= 0; i--) {
+      const ch = code[i];
+      if (ch === '\n') return true;
+      if (ch !== ' ' && ch !== '\t') return false;
+    }
+    return true;
+  }
+
+  /**
+   * Highlight C source code
+   */
+  function highlightC(code) {
+    const tokens = [];
+    let i = 0;
+    const len = code.length;
+
+    while (i < len) {
+      const char = code[i];
+
+      // Multi-line comment
+      if (char === '/' && code[i + 1] === '*') {
+        let end = code.indexOf('*/', i + 2);
+        end = (end === -1) ? len : end + 2;
+        const comment = code.substring(i, end);
+        tokens.push('<span class="c-comment">', escapeHtml(comment), '</span>');
+        i = end;
+        continue;
+      }
+
+      // Single-line comment
+      if (char === '/' && code[i + 1] === '/') {
+        const end = code.indexOf('\n', i);
+        const commentEnd = (end === -1) ? len : end;
+        const comment = code.substring(i, commentEnd);
+        tokens.push('<span class="c-comment">', escapeHtml(comment), '</span>');
+        i = commentEnd;
+        continue;
+      }
+
+      // Preprocessor directive (must be at line start)
+      if (char === '#' && isLineStart(code, i)) {
+        let end = i + 1;
+        while (end < len && code[end] !== '\n') {
+          if (code[end] === '\\' && end + 1 < len && code[end + 1] === '\n') {
+            end += 2; // Handle line continuation
+          } else {
+            end++;
+          }
+        }
+        const preprocessor = code.substring(i, end);
+        tokens.push('<span class="c-preprocessor">', escapeHtml(preprocessor), '</span>');
+        i = end;
+        continue;
+      }
+
+      // String literal
+      if (char === '"') {
+        let end = i + 1;
+        while (end < len && code[end] !== '"') {
+          if (code[end] === '\\' && end + 1 < len) {
+            end += 2; // Skip escaped character
+          } else {
+            end++;
+          }
+        }
+        if (end < len) end++; // Include closing quote
+        const string = code.substring(i, end);
+        tokens.push('<span class="c-string">', escapeHtml(string), '</span>');
+        i = end;
+        continue;
+      }
+
+      // Character literal
+      if (char === "'") {
+        let end = i + 1;
+        // Handle escape sequences like '\n', '\\', '\''
+        if (end < len && code[end] === '\\' && end + 1 < len) {
+          end += 2; // Skip backslash and escaped char
+        } else if (end < len) {
+          end++; // Single character
+        }
+        if (end < len && code[end] === "'") end++; // Closing quote
+        const charLit = code.substring(i, end);
+        tokens.push('<span class="c-value">', escapeHtml(charLit), '</span>');
+        i = end;
+        continue;
+      }
+
+      // Number (integer or float)
+      if (char >= '0' && char <= '9') {
+        let end = i;
+
+        // Hexadecimal
+        if (char === '0' && (code[i + 1] === 'x' || code[i + 1] === 'X')) {
+          end = i + 2;
+          while (end < len) {
+            const ch = code[end];
+            if ((ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'f') || (ch >= 'A' && ch <= 'F')) {
+              end++;
+            } else {
+              break;
+            }
+          }
+        }
+        // Octal
+        else if (char === '0' && code[i + 1] >= '0' && code[i + 1] <= '7') {
+          end = i + 1;
+          while (end < len && code[end] >= '0' && code[end] <= '7') end++;
+        }
+        // Decimal/Float
+        else {
+          while (end < len) {
+            const ch = code[end];
+            if ((ch >= '0' && ch <= '9') || ch === '.') {
+              end++;
+            } else {
+              break;
+            }
+          }
+          // Scientific notation
+          if (end < len && (code[end] === 'e' || code[end] === 'E')) {
+            end++;
+            if (end < len && (code[end] === '+' || code[end] === '-')) end++;
+            while (end < len && code[end] >= '0' && code[end] <= '9') end++;
+          }
+        }
+
+        // Suffix (u, l, f, etc.)
+        while (end < len) {
+          const ch = code[end];
+          if (ch === 'u' || ch === 'U' || ch === 'l' || ch === 'L' || ch === 'f' || ch === 'F') {
+            end++;
+          } else {
+            break;
+          }
+        }
+
+        const number = code.substring(i, end);
+        tokens.push('<span class="c-value">', escapeHtml(number), '</span>');
+        i = end;
+        continue;
+      }
+
+      // Identifier or keyword
+      if ((char >= 'a' && char <= 'z') || (char >= 'A' && char <= 'Z') || char === '_') {
+        let end = i + 1;
+        while (end < len) {
+          const ch = code[end];
+          if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') ||
+              (ch >= '0' && ch <= '9') || ch === '_') {
+            end++;
+          } else {
+            break;
+          }
+        }
+        const word = code.substring(i, end);
+
+        if (C_KEYWORDS.has(word)) {
+          tokens.push('<span class="c-keyword">', escapeHtml(word), '</span>');
+        } else if (isType(word)) {
+          // Check types before macros (VALUE, ID are types, not macros)
+          tokens.push('<span class="c-type">', escapeHtml(word), '</span>');
+        } else if (isMacro(word)) {
+          tokens.push('<span class="c-macro">', escapeHtml(word), '</span>');
+        } else {
+          // Check if followed by '(' -> function name
+          let nextCharIdx = end;
+          while (nextCharIdx < len && (code[nextCharIdx] === ' ' || code[nextCharIdx] === '\t')) {
+            nextCharIdx++;
+          }
+          if (nextCharIdx < len && code[nextCharIdx] === '(') {
+            tokens.push('<span class="c-function">', escapeHtml(word), '</span>');
+          } else {
+            tokens.push('<span class="c-identifier">', escapeHtml(word), '</span>');
+          }
+        }
+        i = end;
+        continue;
+      }
+
+      // Operators
+      if (OPERATOR_CHARS.has(char)) {
+        let op = char;
+        // Check for two-character operators
+        if (i + 1 < len) {
+          const twoChar = char + code[i + 1];
+          if (OPERATORS.has(twoChar)) {
+            op = twoChar;
+          }
+        }
+        tokens.push('<span class="c-operator">', escapeHtml(op), '</span>');
+        i += op.length;
+        continue;
+      }
+
+      // Everything else (punctuation, whitespace)
+      tokens.push(escapeHtml(char));
+      i++;
+    }
+
+    return tokens.join('');
+  }
+
+  /**
+   * Initialize C syntax highlighting on page load
+   */
+  function initHighlighting() {
+    const codeBlocks = document.querySelectorAll('pre[data-language="c"]');
+
+    codeBlocks.forEach(block => {
+      if (block.getAttribute('data-highlighted') === 'true') {
+        return;
+      }
+
+      const code = block.textContent;
+      const highlighted = highlightC(code);
+
+      block.innerHTML = highlighted;
+      block.setAttribute('data-highlighted', 'true');
+    });
+  }
+
+  if (document.readyState === 'loading') {
+    document.addEventListener('DOMContentLoaded', initHighlighting);
+  } else {
+    initHighlighting();
+  }
+})();

lib/rdoc/parser/c.rb

@@ -622,7 +622,7 @@ def find_body(class_name, meth_name, meth_obj, file_content, quiet = false)
       find_modifiers comment, meth_obj if comment
 
       #meth_obj.params = params
-      meth_obj.start_collecting_tokens
+      meth_obj.start_collecting_tokens(:c)
       tk = { :line_no => 1, :char_no => 1, :text => body }
       meth_obj.add_token tk
       meth_obj.comment = comment
@@ -638,7 +638,7 @@ def find_body(class_name, meth_name, meth_obj, file_content, quiet = false)
 
       find_modifiers comment, meth_obj
 
-      meth_obj.start_collecting_tokens
+      meth_obj.start_collecting_tokens(:c)
       tk = { :line_no => 1, :char_no => 1, :text => body }
       meth_obj.add_token tk
       meth_obj.comment = comment