Clean up class handling in the metagrammar and compiler

The class AST node now contains structured data and a raw text which is
used for error messages.

lib/compiler.js

@@ -723,16 +723,23 @@ PEG.Compiler = {
     },
 
     "class": function(node, resultVar) {
-      /*
-       * Stupid IE considers regexps /[]/ and /[^]/ syntactically invalid, so we
-       * translate them into euqivalents it can handle.
-       */
-      if (node.chars === "") {
-        var regexp = "/^(?!)/";
-      } else if (node.chars === "^") {
-        var regexp = "/^[\\S\\s]/";
+      if (node.parts.length > 0) {
+        var regexp = "/^["
+          + (node.inverted ? "^" : "")
+          + PEG.ArrayUtils.map(node.parts, function(part) {
+              return part instanceof Array
+                ? PEG.RegExpUtils.quoteForClass(part[0])
+                  + "-"
+                  + PEG.RegExpUtils.quoteForClass(part[1])
+                : PEG.RegExpUtils.quoteForClass(part);
+            }).join("")
+          + "]/";
       } else {
-        var regexp = "/^[" + node.chars + "]/";
+        /*
+         * Stupid IE considers regexps /[]/ and /[^]/ syntactically invalid, so
+         * we translate them into euqivalents it can handle.
+         */
+        var regexp = node.inverted ? "/^[\\S\\s]/" : "/^(?!)/";
       }
 
       return PEG.Compiler.formatCode(
@@ -742,12 +749,12 @@ PEG.Compiler = {
         "} else {",
         "  var ${resultVar} = null;",
         "  if (context.reportMatchFailures) {",
-        "    this._matchFailed('[' + ${chars|string} + ']');",
+        "    this._matchFailed(${rawText|string});",
         "  }",
         "}",
         {
-          chars:     node.chars,
           regexp:    regexp,
+          rawText:   node.rawText,
           resultVar: resultVar
         }
       );

lib/metagrammar.pegjs

@@ -68,7 +68,7 @@ primary
   : identifier !(( literal / "") colon) { return { type: "rule_ref", name:  $1 }; }
   / literal                             { return { type: "literal",  value: $1 }; }
   / dot                                 { return { type: "any"                 }; }
-  / class                               { return { type: "class",    chars: $1 }; }
+  / class
   / lparen expression rparen            { return $2; }
 
 /* "Lexical" elements */
@@ -142,27 +142,41 @@ singleQuotedCharacter
 simpleSingleQuotedCharacter: !("'" / "\\" / eolChar) . { return $2; }
 
 class "character class": "[" "^"? (classCharacterRange / classCharacter)* "]" __ {
-  return $2 + $3.join("");
+  parts = PEG.ArrayUtils.map($3, function(part) { return part.data; });
+  rawText = "["
+    + $2
+    + PEG.ArrayUtils.map($3, function(part) { return part.rawText; }).join("")
+    + "]";
+
+  return {
+    type:     "class",
+    inverted: $2 === "^",
+    parts:    parts,
+    // FIXME: Get the raw text from the input directly.
+    rawText:  rawText
+  };
 }
 
-classCharacterRange: bracketDelimitedCharacter "-" bracketDelimitedCharacter {
-  if ($1.charCodeAt(0) > $3.charCodeAt(0)) {
+classCharacterRange: classCharacter "-" classCharacter {
+  if ($1.data.charCodeAt(0) > $3.data.charCodeAt(0)) {
     throw new this.SyntaxError(
-      "Invalid character range: "
-        + PEG.RegExpUtils.quoteForClass($1)
-        + "-"
-        + PEG.RegExpUtils.quoteForClass($3)
-        + "."
+      "Invalid character range: " + $1.rawText + "-" + $2.rawText + "."
     );
   }
 
-  return PEG.RegExpUtils.quoteForClass($1)
-    + "-"
-    + PEG.RegExpUtils.quoteForClass($3);
+  return {
+    data:    [$1.data, $3.data],
+    // FIXME: Get the raw text from the input directly.
+    rawText: $1.rawText + "-" + $3.rawText
+  }
 }
 
 classCharacter: bracketDelimitedCharacter {
-  return PEG.RegExpUtils.quoteForClass($1);
+  return {
+    data:    $1,
+    // FIXME: Get the raw text from the input directly.
+    rawText: PEG.RegExpUtils.quoteForClass($1)
+  };
 }
 
 bracketDelimitedCharacter

test/metagrammar-test.js

@@ -81,10 +81,12 @@ function any() {
   return { type: "any" };
 }
 
-function klass(chars) {
+function klass(inverted, parts, rawText) {
   return {
-    type:  "class",
-    chars: chars
+    type:     "class",
+    inverted: inverted,
+    parts:    parts,
+    rawText:  rawText
   };
 }
 
@@ -119,8 +121,8 @@ function literalGrammar(literal) {
   return oneRuleGrammar(literal_(literal));
 }
 
-function classGrammar(chars) {
-  return oneRuleGrammar(klass(chars));
+function classGrammar(inverted, parts, rawText) {
+  return oneRuleGrammar(klass(inverted, parts, rawText));
 }
 
 var anyGrammar = oneRuleGrammar(any());
@@ -224,7 +226,7 @@ test("parses primary", function() {
   grammarParserParses('start: a',        identifierGrammar("a"));
   grammarParserParses('start: "abcd"',   literalGrammar("abcd"));
   grammarParserParses('start: .',        anyGrammar);
-  grammarParserParses('start: [a-d]',    classGrammar("a-d"));
+  grammarParserParses('start: [a-d]',    classGrammar(false, [["a", "d"]], "[a-d]"));
   grammarParserParses('start: ("abcd")', literalGrammar("abcd"));
 });
 
@@ -334,41 +336,44 @@ test("parses simpleSingleQuotedCharacter", function() {
 
 /* Canonical class is "[a-d]". */
 test("parses class", function() {
-  grammarParserParses("start: []",          classGrammar(""));
-  grammarParserParses("start: [a-d]",       classGrammar("a-d"));
-  grammarParserParses("start: [^a-d]",      classGrammar("^a-d"));
-  grammarParserParses("start: [a]",         classGrammar("a"));
-  grammarParserParses("start: [a-de-hi-l]", classGrammar("a-de-hi-l"));
+  grammarParserParses("start: []",     classGrammar(false, [],           "[]"));
+  grammarParserParses("start: [a-d]",  classGrammar(false, [["a", "d"]], "[a-d]"));
+  grammarParserParses("start: [^a-d]", classGrammar(true,  [["a", "d"]], "[^a-d]"));
+  grammarParserParses("start: [a]",    classGrammar(false, ["a"],        "[a]"));
+  grammarParserParses(
+    "start: [a-de-hi-l]",
+    classGrammar(false, [["a", "d"], ["e", "h"], ["i", "l"]], "[a-de-hi-l]")
+  );
 
-  grammarParserParses("start: [a-d]\n", classGrammar("a-d"));
+  grammarParserParses("start: [a-d]\n", classGrammar(false, [["a", "d"]], "[a-d"]));
 });
 
 /* Canonical classCharacterRange is "a-d". */
 test("parses classCharacterRange", function() {
-  grammarParserParses("start: [a-d]", classGrammar("a-d"));
-  grammarParserParses("start: [a-a]", classGrammar("a-a"));
+  grammarParserParses("start: [a-d]", classGrammar(false, [["a", "d"]], "[a-d]"));
+  grammarParserParses("start: [a-a]", classGrammar(false, [["a", "a"]], "[a-d]"));
   grammarParserDoesNotParse("start: [b-a]");
 });
 
 /* Canonical classCharacter is "a". */
 test("parses classCharacter", function() {
-  grammarParserParses("start: [a]", classGrammar("a"));
+  grammarParserParses("start: [a]", classGrammar(false, ["a"], "[a]"));
 });
 
 /* Canonical bracketDelimitedCharacter is "a". */
 test("parses bracketDelimitedCharacter", function() {
-  grammarParserParses("start: [a]",       classGrammar("a"));
-  grammarParserParses("start: [\\n]",     classGrammar("\\n"));
-  grammarParserParses("start: [\\0]",     classGrammar("\\0"));
-  grammarParserParses("start: [\\x00]",   classGrammar("\\0"));
-  grammarParserParses("start: [\\u0120]", classGrammar("\u0120"));
-  grammarParserParses("start: [\\\n]",    classGrammar("\\n"));
+  grammarParserParses("start: [a]",       classGrammar(false, ["a"]));
+  grammarParserParses("start: [\\n]",     classGrammar(false, ["\n"]));
+  grammarParserParses("start: [\\0]",     classGrammar(false, ["\0"]));
+  grammarParserParses("start: [\\x00]",   classGrammar(false, ["\0"]));
+  grammarParserParses("start: [\\u0120]", classGrammar(false, ["\u0120"]));
+  grammarParserParses("start: [\\\n]",    classGrammar(false, ["\n"]));
 });
 
 /* Canonical simpleBracketDelimiedCharacter is "a". */
 test("parses simpleBracketDelimitedCharacter", function() {
-  grammarParserParses("start: [a]",  classGrammar("a"));
-  grammarParserParses("start: [[]",  classGrammar("["));
+  grammarParserParses("start: [a]",  classGrammar(false, ["a"]));
+  grammarParserParses("start: [[]",  classGrammar(false, ["["]));
   grammarParserDoesNotParse("start: []]");
   grammarParserDoesNotParse("start: [\\]");
   grammarParserDoesNotParse("start: [\n]");