Add comments, allow slashes in unquoted attribute values

Co-Authored-By: Ashi Krishan <queerviolet@github.com>

corpus/main.txt

@@ -71,3 +71,19 @@ Void tags
         (attribute (attribute_name) (attribute_value))
         (attribute (attribute_name) (attribute_value))))
     (end_tag)))
+
+==================================
+Comments
+==================================
+<!-- hello -->
+<div>
+  <!-- <span>something</span> -->
+</div>
+---
+
+(fragment
+  (comment)
+  (element
+    (start_tag)
+    (comment)
+    (end_tag)))

grammar.js

@@ -1,6 +1,11 @@
 module.exports = grammar({
   name: 'html',
 
+  extras: $ => [
+    $.comment,
+    /\s+/,
+  ],
+
   externals: $ => [
     $._open_start_tag,
     $._close_start_tag,
@@ -8,6 +13,7 @@ module.exports = grammar({
     $.end_tag,
     $._implicit_end_tag,
     $._erroneous_end_tag,
+    $.comment,
   ],
 
   rules: {
@@ -41,17 +47,19 @@ module.exports = grammar({
     ),
 
     attribute: $ => seq(
-      alias($._attribute_part, $.attribute_name),
+      $.attribute_name,
       optional(seq(
         '=',
         choice(
-          alias($._attribute_part, $.attribute_value),
+          $.attribute_value,
           $.quoted_attribute_value
         )
       ))
     ),
 
-    _attribute_part: $ => /[^<>"'/=\s]+/,
+    attribute_name: $ => /[^<>"'/=\s]+/,
+
+    attribute_value: $ => /[^<>"'=\s]+/,
 
     quoted_attribute_value: $ => choice(
       seq("'", optional(alias(/[^']+/, $.attribute_value)), "'"),

src/grammar.json

@@ -107,13 +107,8 @@
       "type": "SEQ",
       "members": [
         {
-          "type": "ALIAS",
-          "content": {
           "type": "SYMBOL",
-            "name": "_attribute_part"
-          },
-          "named": true,
-          "value": "attribute_name"
+          "name": "attribute_name"
         },
         {
           "type": "CHOICE",
@@ -129,13 +124,8 @@
                   "type": "CHOICE",
                   "members": [
                     {
-                      "type": "ALIAS",
-                      "content": {
                       "type": "SYMBOL",
-                        "name": "_attribute_part"
-                      },
-                      "named": true,
-                      "value": "attribute_value"
+                      "name": "attribute_value"
                     },
                     {
                       "type": "SYMBOL",
@@ -152,10 +142,14 @@
         }
       ]
     },
-    "_attribute_part": {
+    "attribute_name": {
       "type": "PATTERN",
       "value": "[^<>\"'\\/=\\s]+"
     },
+    "attribute_value": {
+      "type": "PATTERN",
+      "value": "[^<>\"'=\\s]+"
+    },
     "quoted_attribute_value": {
       "type": "CHOICE",
       "members": [
@@ -227,9 +221,13 @@
     }
   },
   "extras": [
+    {
+      "type": "SYMBOL",
+      "name": "comment"
+    },
     {
       "type": "PATTERN",
-      "value": "\\s"
+      "value": "\\s+"
     }
   ],
   "conflicts": [],
@@ -257,6 +255,10 @@
     {
       "type": "SYMBOL",
       "name": "_erroneous_end_tag"
+    },
+    {
+      "type": "SYMBOL",
+      "name": "comment"
     }
   ],
   "inline": []

src/scanner.cc

@@ -18,6 +18,7 @@ enum TokenType {
   END_TAG,
   IMPLICIT_END_TAG,
   ERRONEOUS_END_TAG,
+  COMMENT,
 };
 
 struct Scanner {
@@ -66,7 +67,43 @@ struct Scanner {
     return tag_name;
   }
 
+  bool comment(TSLexer *lexer) {
+    if (lexer->lookahead != '-') return false;
+    lexer->advance(lexer, false);
+    if (lexer->lookahead != '-') return false;
+    lexer->advance(lexer, false);
+
+    unsigned dashes = 0;
+    auto c = lexer->lookahead;
+    while (c) {
+      switch (c) {
+        case '-':
+          ++dashes;
+          break;
+        case '>':
+          if (dashes >= 2) {
+            lexer->result_symbol = COMMENT;
+            lexer->advance(lexer, false);
+            lexer->mark_end(lexer);
+            return true;
+          }
+          break;
+        default:
+          dashes = 0;
+      }
+      lexer->advance(lexer, false);
+      c = lexer->lookahead;
+    }
+    return false;
+  }
+
   bool start_tag(TSLexer *lexer) {
+    if (!tags.empty() && tags.back().is_void()) {
+      tags.pop_back();
+      lexer->result_symbol = IMPLICIT_END_TAG;
+      return true;
+    }
+
     auto tag_name = scan_tag_name(lexer);
     if (tag_name.empty()) return false;
 
@@ -115,15 +152,22 @@ struct Scanner {
 
     switch (lexer->lookahead) {
       case '<':
-        if (valid_symbols[OPEN_START_TAG] || valid_symbols[END_TAG]) {
         lexer->mark_end(lexer);
         lexer->advance(lexer, false);
+
+        if (lexer->lookahead == '!') {
+          lexer->advance(lexer, false);
+          return comment(lexer);
+        }
+
+        if (valid_symbols[OPEN_START_TAG] || valid_symbols[END_TAG]) {
           if (lexer->lookahead == '/') {
             lexer->advance(lexer, false);
             return end_tag(lexer);
           }
           return start_tag(lexer);
         }
+
         break;
 
       case '>':

test.html

@@ -1 +0,0 @@
-<form><img src=something.png><br><input type=submit value=Ok /></form>