Merge pull request #24 from sass/serialize-color

Match Ruby Sass's color serialization.

CHANGELOG.md

@@ -1,3 +1,9 @@
+## 1.0.0-alpha.3
+
+* Emit colors using their original representation if possible.
+
+* Emit colors without an original representation as names if possible.
+
 ## 1.0.0-alpha.2
 
 * Fix a bug where variables, functions, and mixins were broken in imported

lib/src/color_names.dart

@@ -2,6 +2,8 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
+import 'package:collection/collection.dart';
+
 import 'utils.dart';
 import 'value.dart';
 
@@ -157,3 +159,9 @@ final colorsByName = normalizedMap({
   'yellow': new SassColor.rgb(0xFF, 0xFF, 0x00),
   'yellowgreen': new SassColor.rgb(0x9A, 0xCD, 0x32),
 });
+
+/// A map from Sass colors to (lowercase) color names.
+final namesByColor = mapMap/*<String, SassColor, SassColor, String>*/(
+    colorsByName,
+    key: (_, color) => color,
+    value: (name, _) => name);

lib/src/parse/stylesheet.dart

@@ -15,6 +15,7 @@ import '../interpolation_buffer.dart';
 import '../util/character.dart';
 import '../utils.dart';
 import '../value.dart';
+import '../value/color.dart';
 import 'parser.dart';
 
 /// The base class for both the SCSS and indented syntax parsers.
@@ -1492,14 +1493,20 @@ abstract class StylesheetParser extends Parser {
 
     var first = scanner.peekChar();
     if (first != null && isDigit(first)) {
-      return new ColorExpression(_hexColorContents(), scanner.spanFrom(start));
+      var color = _hexColorContents();
+      var span = scanner.spanFrom(start);
+      setOriginalSpan(color, span);
+      return new ColorExpression(color, span);
     }
 
     var afterHash = scanner.state;
     var identifier = _interpolatedIdentifier();
     if (_isHexColor(identifier)) {
       scanner.state = afterHash;
-      return new ColorExpression(_hexColorContents(), scanner.spanFrom(start));
+      var color = _hexColorContents();
+      var span = scanner.spanFrom(start);
+      setOriginalSpan(color, span);
+      return new ColorExpression(color, span);
     }
 
     var buffer = new InterpolationBuffer();
@@ -1740,7 +1747,13 @@ abstract class StylesheetParser extends Parser {
         }
 
         var color = colorsByName[lower];
-        if (color != null) return new ColorExpression(color, identifier.span);
+        if (color != null) {
+          // TODO(nweiz): Avoid copying the color in compressed mode.
+          color = new SassColor.rgb(
+              color.red, color.green, color.blue, color.alpha);
+          setOriginalSpan(color, identifier.span);
+          return new ColorExpression(color, identifier.span);
+        }
       }
 
       var specialFunction = _trySpecialFunction(lower, start);

lib/src/value.dart

@@ -16,7 +16,7 @@ import 'visitor/serialize.dart';
 
 export 'value/argument_list.dart';
 export 'value/boolean.dart';
-export 'value/color.dart';
+export 'value/color.dart' hide setOriginalSpan;
 export 'value/function.dart';
 export 'value/list.dart';
 export 'value/map.dart';

lib/src/value/color.dart

@@ -4,11 +4,20 @@
 
 import 'dart:math' as math;
 
+import 'package:source_span/source_span.dart';
+
 import '../exception.dart';
 import '../util/number.dart';
 import '../value.dart';
 import '../visitor/interface/value.dart';
 
+/// Sets the span for [SassColor.original] to [span].
+///
+/// This is a separate function so it can be hidden in most exports.
+void setOriginalSpan(SassColor color, SourceSpan span) {
+  color._originalSpan = span;
+}
+
 // TODO(nweiz): track original representation.
 /// A SassScript color.
 class SassColor extends Value {
@@ -63,6 +72,15 @@ class SassColor extends Value {
   /// This color's alpha channel, between `0` and `1`.
   final num alpha;
 
+  /// The original string representation of this color, or `null` if one is
+  /// unavailable.
+  String get original => _originalSpan?.text;
+
+  /// The span tracking the location in which this color was originally defined.
+  ///
+  /// This is tracked as a span to avoid extra substring allocations.
+  SourceSpan _originalSpan;
+
   /// Creates an RGB color.
   ///
   /// Throws a [RangeError] if [red], [green], and [blue] aren't between `0` and

lib/src/visitor/serialize.dart

@@ -10,6 +10,7 @@ import 'package:string_scanner/string_scanner.dart';
 
 import '../ast/css.dart';
 import '../ast/selector.dart';
+import '../color_names.dart';
 import '../exception.dart';
 import '../util/character.dart';
 import '../util/number.dart';
@@ -280,8 +281,11 @@ class _SerializeCssVisitor
   void visitBoolean(SassBoolean value) => _buffer.write(value.value.toString());
 
   void visitColor(SassColor value) {
-    // TODO(nweiz): Use color names for named colors.
-    if (value.alpha == 1) {
+    if (value.original != null) {
+      _buffer.write(value.original);
+    } else if (namesByColor.containsKey(value)) {
+      _buffer.write(namesByColor[value]);
+    } else if (value.alpha == 1) {
       _buffer.writeCharCode($hash);
       _writeHexComponent(value.red);
       _writeHexComponent(value.green);

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass
-version: 1.0.0-alpha.2
+version: 1.0.0-dev
 description: A Sass implementation in Dart.
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/sass/dart-sass