Beginning of CSS parser using frog parsering infrastructure.

utils/css/tokenizer.dart

+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+class Tokenizer extends lang.TokenizerBase {
+  TokenKind cssTokens;
+
+  Tokenizer(lang.SourceFile source, bool skipWhitespace, [int index = 0])
+    : super(source, skipWhitespace, index) {
+    cssTokens = new TokenKind();
+  }
+
+  lang.Token next() {
+    // keep track of our starting position
+    _startIndex = _index;
+
+    if (_interpStack != null && _interpStack.depth == 0) {
+      var istack = _interpStack;
+      _interpStack = _interpStack.pop();
+/*

[jimhug, 2011/11/10 17:58:56]

Is this relevant at all for css?

[terry, 2011/11/16 14:00:22]

I think we might want this for string interpolation in CSS however, it's not
used yet.

$type = 'gif'
url('image.${type}')  or   url('image.#{$type}')

or

div::before {
  content: "Chapter ${counter(chapter)} : -- "
}

for long strings but this might be rare.  My goal is to have a consistent
interpolation in CSS, Dart, HTML, etc. 

We could allow intrinsic CSS function calls inside of the curlys too with
parameters passed.

However, the commented out code will be removed for now.
On 2011/11/10 17:58:56, jimhug wrote:

+      if (istack.isMultiline) {
+        return finishMultilineStringBody(istack.quote);
+      } else {
+        return finishStringBody(istack.quote);
+      }
+*/
+    }
+
+    int ch;
+    ch = _nextChar();
+    switch(ch) {
+      case 0:
+        return _finishToken(TokenKind.END_OF_FILE);
+      case TokenizerHelpers.WS_SPACE:
+      case TokenizerHelpers.WS_TAB:
+      case TokenizerHelpers.WS_NEWLINE:
+      case TokenizerHelpers.WS_RETURN:
+        return finishWhitespace();
+      case cssTokens.tokens[TokenKind.END_OF_FILE]:
+        return _finishToken(TokenKind.END_OF_FILE);
+      case cssTokens.tokens[TokenKind.AT]:
+        return _finishToken(TokenKind.AT);
+      case cssTokens.tokens[TokenKind.DOT]:
+        return _finishToken(TokenKind.DOT);
+      case cssTokens.tokens[TokenKind.LBRACE]:
+        return _finishToken(TokenKind.LBRACE);
+      case cssTokens.tokens[TokenKind.RBRACE]:
+        return _finishToken(TokenKind.RBRACE);
+      case cssTokens.tokens[TokenKind.HASH]:
+        return _finishToken(TokenKind.HASH);
+      case cssTokens.tokens[TokenKind.COMBINATOR_PLUS]:
+        return _finishToken(TokenKind.COMBINATOR_PLUS);
+      case cssTokens.tokens[TokenKind.COMBINATOR_GREATER]:
+        return _finishToken(TokenKind.COMBINATOR_GREATER);
+      case cssTokens.tokens[TokenKind.COMBINATOR_TILDE]:
+        return _finishToken(TokenKind.COMBINATOR_TILDE);
+      case cssTokens.tokens[TokenKind.ASTERISK]:
+        return _finishToken(TokenKind.ASTERISK);
+      case cssTokens.tokens[TokenKind.NAMESPACE]:
+        return _finishToken(TokenKind.NAMESPACE);
+      case cssTokens.tokens[TokenKind.PSEUDO]:
+        return _finishToken(TokenKind.PSEUDO);
+      case cssTokens.tokens[TokenKind.COMMA]:
+        return _finishToken(TokenKind.COMMA);
+
+      default:
+        if (isIdentifierStart(ch)) {
+          return this.finishIdentifier();
+        } else if (isDigit(ch)) {
+          return this.finishNumber();
+        } else {
+          return _errorToken();
+        }
+    }
+  }
+
+  // TODO(jmesserly): we need a way to emit human readable error messages from
+  // the tokenizer.
+  lang.Token _errorToken() {
+    return _finishToken(TokenKind.ERROR);
+  }
+
+  int getIdentifierKind() {
+    return TokenKind.IDENTIFIER;
+  }
+
+  // Need to override so CSS version of isIdentifierPart is used.
+  lang.Token finishIdentifier() {
+    while (_index < _text.length) {
+      if (!TokenizerHelpers.isIdentifierPart(_text.charCodeAt(_index++))) {
+        _index--;
+        break;
+      }
+    }
+    int kind = getIdentifierKind();
+    if (_interpStack != null && _interpStack.depth == -1) {
+      _interpStack.depth = 0;
+    }
+    if (kind == TokenKind.IDENTIFIER) {
+      return _finishToken(TokenKind.IDENTIFIER);
+    } else {
+      return _finishToken(kind);
+    }
+  }
+
+}
+
+/** Static helper methods. */
+class TokenizerHelpers {

[jimhug, 2011/11/10 17:58:56]

Any reason not to use lang.TokenizerHelpers here?  It looks like you'd just need
to implement
  isCssIdentifierPart(int c) => TokenizerHelpers.isIdentifierPart(c) || c ==
45/*-*/;
But, maybe I'm missing something...

[terry, 2011/11/16 14:00:22]

Good point.
Done.

+  final static int WS_SPACE = 32;                       // ' '
+  final static int WS_TAB = 9;                          // '\t'
+  final static int WS_NEWLINE = 10;                     // '\n'
+  final static int WS_RETURN = 13;                      // '\r'
+
+  static bool isIdentifierStart(int c) {
+    return ((c >= 97/*a*/ && c <= 122/*z*/) || (c >= 65/*A*/ && c <= 90/*Z*/) || c == 95/*_*/);
+  }
+
+  static bool isDigit(int c) {
+    return (c >= 48/*0*/ && c <= 57/*9*/);
+  }
+
+  static bool isHexDigit(int c) {
+    return (isDigit(c) || (c >= 97/*a*/ && c <= 102/*f*/) || (c >= 65/*A*/ && c <= 70/*F*/));
+  }
+
+  static bool isWhitespace(int c) {
+    return (c == 32/*' '*/ || c == 9/*'\t'*/ || c == 10/*'\n'*/ || c == 13/*'\r'*/);
+  }
+
+  static bool isIdentifierPart(int c) {
+    return (isIdentifierStart(c) || isDigit(c) || c == 45/*-*/);
+  }
+}