Beginning of CSS parser using frog parsering infrastructure.

frog/css/tree_css.dart

Index: frog/css/tree_css.dart
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+// 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.
+// Generated by scripts/tree_gen.py.
+
+/////////////////////////////////////////////////////////////////////////
+// CSS specific types:
+/////////////////////////////////////////////////////////////////////////
+
+
+// TODO(terry): Type and TypeParameter defined for frog/tree.dart. 
+class Type { }
+class TypeParameter extends Node { }
+
+
+class Identifier extends Node {
+  String name;
+
+  Identifier(this.name, SourceSpan span): super(span) {}
+
+  visit(TreeVisitor visitor) => visitor.visitIdentifier(this);
+
+  String toString() => name;
+}
+
+class SelectorGroup extends Node {
+  // List of SimpleSelector(s) list contain any mix SimpleSelector or
+  // SimpleSlectorName (or class derived from SimpleSelectorName e.g.,
+  // IdSelector, ClassSelector, ElementSelector, PseudoClassSelector,
+  // PseudoElementSelector, NotSelector, or Attribute
+  List<Node> selectors;

[nweiz, 2011/11/10 00:04:39]

Why isn't this List<SimpleSelector>?

[terry, 2011/11/22 16:40:47]

Should be.
Done.

+
+  SelectorGroup(this.selectors, SourceSpan span): super(span) {}
+
+  visit(TreeVisitor visitor) => visitor.visitSelectorGroup(this);
+
+  String toString() {
+    StringBuffer buff = new StringBuffer();
+    for (selector in selectors) {
+      buff.add(selector.toString());
+      buff.add(' ');
+    }
+    return buff.toString();
+  }
+}
+

[nweiz, 2011/11/10 00:04:39]

As mentioned elsewhere, there should be a representation of sequences of simple
selectors as distinct from selectors and groups of selectors.

[terry, 2011/11/22 16:40:47]

Yep added combinator descendant (space) and NONE.
On 2011/11/10 00:04:39, nweiz wrote:

+/* All other selectors (element, #id, .class, attribute, pseudo, negation,
+ * namespace, *) are derived from this selector.
+ */
+class SimpleSelector extends Node {
+  Token _combinator;     // +, >, ~ or NONE (space)

[nweiz, 2011/11/10 00:04:39]

Related to the sequence of simple selector issue, it doesn't make sense to map
simple selectors one-to-one with combinators. ".foo.bar" is different than ".foo
.bar".

[terry, 2011/11/22 16:40:47]

I have for now maybe I'm being too pedantic (even though the syntax doesn't
require it) I'll recheck why I thought I needed this.
On 2011/11/10 00:04:39, nweiz wrote:

+
+  // name is of type IdSelector, ClassSelector, ElementSelector,
+  // PseudoClassSelector, PseudoElementSelector, NotSelector, or Attribute

[nweiz, 2011/11/10 00:04:39]

Is this really true? Aren't all these subclasses of SimpleSelector? Why does it
have a field that's a subclass of itself?

[terry, 2011/11/22 16:40:47]

No comment is outdated.
On 2011/11/10 00:04:39, nweiz wrote:

+  var _name;
+
+  SimpleSelector(this._name, [this._combinator = TokenKind.COMBINATOR_NONE]);
+
+  // Wildcard can be a String just return _name otherwise if identifier we'll
+  // drill into the Identifier and return it's name.
+  String get name() => _name is Identifier ? _name.name : _name;

[nweiz, 2011/11/10 00:04:39]

Ah, so _name is an Identifier or a String. Why does it have two different types?
Is the Identifier form ever used? Don't some simple selectors not really even
have names?

[terry, 2011/11/22 16:40:47]

It's an identifier or wildcard nothing else String was bad I eventually removed
that.
On 2011/11/10 00:04:39, nweiz wrote:

+
+  bool isCombinatorNone() => _combinator == TokenKind.COMBINATOR_NONE;
+  bool isCombinatorPlus() => _combinator == TokenKind.COMBINATOR_PLUS;
+  bool isCombinatorGreater() => _combinator == TokenKind.COMBINATOR_GREATER;
+  bool isCombinatorTilde() => _combinator == TokenKind.COMBINATOR_TILDE;
+
+  visit(TreeVisitor visitor) => visitor.visitSimpleSelectorName(this);
+
+  String toString() => name;
+}
+
+// element name
+class ElementSelector extends SimpleSelector {
+  ElementSelector(String name, [Token combinator = TokenKind.COMBINATOR_NONE]) :
+      super(name, combinator);
+
+  bool isWildcard() => name == '*';

[nweiz, 2011/11/10 00:04:39]

A universal selector is not really the same thing as an element selector.

[terry, 2011/11/22 16:40:47]

Your right I removed it when I added notion of wildcard for name.
On 2011/11/10 00:04:39, nweiz wrote:

+
+  visit(TreeVisitor visitor) => visitor.visitElementSelector(this);
+
+  String toString() => "$name";
+}
+
+// namespace|element
+class NamespaceSelector extends SimpleSelector {
+  var _namespace;           // null, '*' or identifier name
+
+  NamespaceSelector(this._namespace, String name,
+      [Token combinator = TokenKind.COMBINATOR_NONE]) : super(name, combinator);

[nweiz, 2011/11/10 00:04:39]

I really don't like the overloading of _name that's going on here. The element
contained by a namespace selector is not its name.

[terry, 2011/11/22 16:40:47]

Right it's an identifier or wildcard.
On 2011/11/10 00:04:39, nweiz wrote:

+
+  String get namespace() => _namespace is Identifier ?

[nweiz, 2011/11/10 00:04:39]

Same comment as SimpleSelector._name above.

[terry, 2011/11/22 16:40:47]

namespace is never a string either Identifier or Wildcard.
On 2011/11/10 00:04:39, nweiz wrote:

+      _namespace.name : _namespace;
+
+  bool isWildcardElement() => _name.isWildcard();

[nweiz, 2011/11/10 00:04:39]

Why is this something that goes through NamespaceSelector?

[terry, 2011/11/22 16:40:47]

Shouldn't it's on simpleSelector.
On 2011/11/10 00:04:39, nweiz wrote:

+
+  bool isNamespaceWildcard() => _namespace == '*';
+
+  SimpleSelector get nameAsElementSelector() => _name;
+
+  visit(TreeVisitor visitor) => visitor.visitNamespaceSelector(this);
+
+  String toString() => "$namespace|$name";
+}
+
+// #id
+class IdSelector extends SimpleSelector {
+  IdSelector(String name, [Token combinator = TokenKind.COMBINATOR_NONE]) :
+    super(name, combinator);
+
+  visit(TreeVisitor visitor) => visitor.visitIdSelector(this);
+
+  String toString() => "#$name";
+}
+
+// .class
+class ClassSelector extends SimpleSelector {
+  ClassSelector(String name, [Token combinator = TokenKind.COMBINATOR_NONE]) :
+    super(name, combinator);
+
+  visit(TreeVisitor visitor) => visitor.visitClassSelector(this);
+
+  String toString() => ".$name";
+}
+
+// :pseudoClass
+class PseudoClassSelector extends SimpleSelector {
+  PseudoClassSelector(String name,
+      [Token combinator = TokenKind.COMBINATOR_NONE]) : super(name, combinator);
+
+  visit(TreeVisitor visitor) => visitor.visitPseudoClassSelector(this);
+
+  String toString() => ":$name";
+}
+
+// ::pseudoElement
+class PseudoElementSelector extends SimpleSelector {
+  PseudoElementSelector(String name,
+      [Token combinator = TokenKind.COMBINATOR_NONE]) : super(name, combinator);
+
+  visit(TreeVisitor visitor) => visitor.visitPseudoElementSelector(this);
+
+  String toString() => "::$name";
+}
+
+// TODO(terry): Implement
+// NOT
+class NotSelector extends SimpleSelector {
+  NotSelector(String name, [Token combinator = TokenKind.COMBINATOR_NONE]) :
+    super(name, combinator);
+
+  visit(TreeVisitor visitor) => visitor.visitNotSelector(this);
+}
+
+// TODO(terry): Implement
+// [attribute]
+class Attribute extends Node {
+  var name;         // NamespaceSelector or SimpleSelector
+  int matchType;    // ~=, |=, ^=, $=, *=, =
+  String value;
+}
+
+interface TreeVisitor {
+  void visitSelectorGroup(SelectorGroup node);
+  void visitSimpleSelector(SimpleSelector node);
+  void visitElementSelector(ElementSelector node);
+  void visitNamespaceSelector(NamespaceSelector node);
+  void visitIdSelector(IdSelector node);
+  void visitClassSelector(ClassSelector node);
+  void visitPseudoClassSelector(PseudoClassSelector node);
+  void visitPseudoElementSelector(PseudoElementSelector node);
+  void visitNotSelector(NotSelector node);
+  
+  void visitIdentifier(Identifier node);
+
+  // TODO(terry): Defined for ../tree.dart.
+  void visitTypeReference(TypeReference node);
+}
+
+class TreePrinter implements TreeVisitor {
+  var output;
+  TreePrinter(this.output) { output.printer = this; }
+
+  void visitSelectorGroup(SelectorGroup node) {
+    output.heading('Selector Group', node.span);
+    output.writeNodeList('selectors', node.selectors);
+    output.writeln('');
+  }
+
+  void visitSimpleSelector(SimpleSelector node) {
+    if (node.isCombinatorNone()) {
+      output.writeValue('combinator', "NONE");
+    } else if (node.isCombinatorPlus()) {
+      output.writeValue('combinator', "+");
+    } else if (node.isCombinatorGreater()) {
+      output.writeValue('combinator', ">");
+    } else if (node.isCombinatorTilde()) {
+      output.writeValue('combinator', "~");
+    } else {
+      output.writeValue('combinator', "ERROR UNKNOWN");
+    }
+  }
+
+  void visitNamespaceSelector(NamespaceSelector node) {
+    output.heading('Namespace Selector', node.span);
+    visitSimpleSelector(node);
+    output.writeValue('namespace', node._namespace);
+    output.writeNode('name', node._name);
+  }
+
+  void visitElementSelector(ElementSelector node) {
+    output.heading('Element Selector', node.span);
+    visitSimpleSelector(node);
+    if (node.isWildcard()) {
+      output.writeValue('name', '*');
+    } else {
+      output.writeNode('name', node.name);
+    }
+  }
+
+  void visitIdSelector(IdSelector node) {
+    output.heading('Id Selector', node.span);
+    visitSimpleSelector(node);
+    output.writeNode('name', node._name);
+  }
+
+  void visitClassSelector(ClassSelector node) {
+    output.heading('Class Selector', node.span);
+    visitSimpleSelector(node);
+    output.writeNode('name', node._name);
+  }
+
+  void visitPseudoClassSelector(PseudoClassSelector node) {
+    output.heading('Pseudo Class Selector', node.span);
+    visitSimpleSelector(node);
+    output.writeNode('name', node._name);
+  }
+
+  void visitPseudoElementSelector(PseudoElementSelector node) {
+    output.heading('Pseudo Element Selector', node.span);
+    visitSimpleSelector(node);
+    output.writeNode('name', node._name);
+  }
+
+  void visitNotSelector(NotSelector node) {
+    visitSimpleSelector(node);
+    output.heading('Not Selector', node.span);
+  }
+
+  void visitIdentifier(Identifier node) {
+    output.heading('Identifier(' + output.toValue(node.name) + ")", node.span);
+  }
+
+  // TODO(terry): Defined for frog/tree.dart.
+  void visitTypeReference(TypeReference node) {
+    output.heading('Unimplemented');
+  }
+}