Properly parse multi-line selectors in the indented syntax (#243)

Closes #235
Closes #237

CHANGELOG.md

@@ -2,18 +2,21 @@
 
 * Support hard tabs in the indented syntax.
 
-* Don't deadlock on `/*` comments in the indented syntax.
-
-* Don't add an extra `*/` to comments in the indented syntax that already have
-  it.
-
 * Improve the formatting of comments that don't start on the same line as the
   opening `/*`.
 
-* Preserve empty lines in `/*` comments in the indented syntax.
-
 * Preserve whitespace after `and` in media queries in compressed mode.
 
+### Indented Syntax
+
+* Properly parse multi-line selectors.
+
+* Don't deadlock on `/*` comments.
+
+* Don't add an extra `*/` to comments that already have it.
+
+* Preserve empty lines in `/*` comments.
+
 ## 1.0.0-beta.5.2
 
 * Fix a bug where some colors would crash `compressed` mode.

lib/src/parse/sass.dart

@@ -39,6 +39,19 @@ class SassParser extends StylesheetParser {
   SassParser(String contents, {url, bool color: false})
       : super(contents, url: url, color: color);
 
+  Interpolation styleRuleSelector() {
+    var start = scanner.state;
+
+    var buffer = new InterpolationBuffer();
+    do {
+      buffer.addInterpolation(almostAnyValue());
+      buffer.writeCharCode($lf);
+    } while (buffer.trailingString.trimRight().endsWith(",") &&
+        scanCharIf(isNewline));
+
+    return buffer.interpolation(scanner.spanFrom(start));
+  }
+
   void expectStatementSeparator([String name]) {
     if (!atEndOfStatement()) scanner.expectChar($lf);
     if (_peekIndentation() <= currentIndentation) return;

lib/src/parse/scss.dart

@@ -17,6 +17,8 @@ class ScssParser extends StylesheetParser {
   ScssParser(String contents, {url, bool color: false})
       : super(contents, url: url, color: color);
 
+  Interpolation styleRuleSelector() => almostAnyValue();
+
   void expectStatementSeparator([String name]) {
     whitespaceWithoutComments();
     if (scanner.isDone) return;

lib/src/parse/stylesheet.dart

@@ -173,7 +173,7 @@ abstract class StylesheetParser extends Parser {
     if (indented) scanner.scanChar($backslash);
 
     var start = scanner.state;
-    var selector = _almostAnyValue();
+    var selector = styleRuleSelector();
     var children = this.children(_statement);
     var rule = new StyleRule(selector, children, scanner.spanFrom(start));
     _inStyleRule = wasInStyleRule;
@@ -218,7 +218,7 @@ abstract class StylesheetParser extends Parser {
     if (declarationOrBuffer is Declaration) return declarationOrBuffer;
 
     var buffer = declarationOrBuffer as InterpolationBuffer;
-    buffer.addInterpolation(_almostAnyValue());
+    buffer.addInterpolation(styleRuleSelector());
     var selectorSpan = scanner.spanFrom(start);
 
     var wasInStyleRule = _inStyleRule;
@@ -320,7 +320,7 @@ abstract class StylesheetParser extends Parser {
       // If the value would be followed by a semicolon, it's definitely supposed
       // to be a property, not a selector.
       scanner.state = beforeDeclaration;
-      var additional = _almostAnyValue();
+      var additional = almostAnyValue();
       if (!indented && scanner.peekChar() == $semicolon) rethrow;
 
       nameBuffer.write(midBuffer);
@@ -593,7 +593,7 @@ abstract class StylesheetParser extends Parser {
           position: start.position, length: "@extend".length);
     }
 
-    var value = _almostAnyValue();
+    var value = almostAnyValue();
     var optional = scanner.scanChar($exclamation);
     if (optional) expectIdentifier("optional");
     expectStatementSeparator("@extend rule");
@@ -983,7 +983,7 @@ abstract class StylesheetParser extends Parser {
 
     Interpolation value;
     var next = scanner.peekChar();
-    if (next != $exclamation && !atEndOfStatement()) value = _almostAnyValue();
+    if (next != $exclamation && !atEndOfStatement()) value = almostAnyValue();
 
     var children = lookingAtChildren() ? this.children(_statement) : null;
     if (children == null) expectStatementSeparator();
@@ -1000,7 +1000,7 @@ abstract class StylesheetParser extends Parser {
   /// This declares a return type of [Statement] so that it can be returned
   /// within case statements.
   Statement _disallowedAtRule(LineScannerState start) {
-    _almostAnyValue();
+    almostAnyValue();
     scanner.error("This at-rule is not allowed here.",
         position: start.position,
         length: scanner.state.position - start.position);
@@ -2228,7 +2228,8 @@ abstract class StylesheetParser extends Parser {
   /// * This supports Sass-style single-line comments.
   ///
   /// * This does not compress adjacent whitespace characters.
-  Interpolation _almostAnyValue() {
+  @protected
+  Interpolation almostAnyValue() {
     var start = scanner.state;
     var buffer = new InterpolationBuffer();
 
@@ -2747,6 +2748,10 @@ abstract class StylesheetParser extends Parser {
   @protected
   int get currentIndentation;
 
+  /// Parses and returns a selector used in a style rule.
+  @protected
+  Interpolation styleRuleSelector();
+
   /// Asserts that the scanner is positioned before a statement separator, or at
   /// the end of a list of statements.
   ///