Make PlatformSelector use boolean_selector.

lib/src/backend/platform_selector/parser.dart

Index: lib/src/backend/platform_selector/parser.dart
diff --git a/lib/src/backend/platform_selector/parser.dart b/lib/src/backend/platform_selector/parser.dart
deleted file mode 100644
index 4a08025adc8f65ee0a4b6274779138e4cc2fe06a..0000000000000000000000000000000000000000
--- a/lib/src/backend/platform_selector/parser.dart
+++ /dev/null
@@ -1,105 +0,0 @@
-// Copyright (c) 2015, 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.
-
-import 'package:source_span/source_span.dart';
-
-import 'ast.dart';
-import 'scanner.dart';
-import 'token.dart';
-
-/// A class for parsing a platform selector.
-///
-/// Platform selectors use a stripped-down version of the Dart expression
-/// syntax that only contains variables, parentheses, and boolean operators.
-/// Variables may also contain dashes, contrary to Dart's syntax; this allows
-/// consistency with command-line arguments.
-class Parser {
-  /// The scanner that tokenizes the selector.
-  final Scanner _scanner;
-
-  Parser(String selector)
-      : _scanner = new Scanner(selector);
-
-  /// Parses the selector.
-  ///
-  /// This must only be called once per parser.
-  Node parse() {
-    var selector = _conditional();
-
-    if (_scanner.peek().type != TokenType.endOfFile) {
-      throw new SourceSpanFormatException(
-          "Expected end of input.", _scanner.peek().span);
-    }
-
-    return selector;
-  }
-
-  /// Parses a conditional:
-  ///
-  ///     conditionalExpression:
-  ///       logicalOrExpression ("?" conditionalExpression ":"
-  ///           conditionalExpression)?
-  Node _conditional() {
-    var condition = _or();
-    if (!_scanner.scan(TokenType.questionMark)) return condition;
-
-    var whenTrue = _conditional();
-    if (!_scanner.scan(TokenType.colon)) {
-      throw new SourceSpanFormatException(
-          'Expected ":".', _scanner.peek().span);
-    }
-
-    var whenFalse = _conditional();
-    return new ConditionalNode(condition, whenTrue, whenFalse);
-  }
-
-  /// Parses a logical or:
-  ///
-  ///     logicalOrExpression:
-  ///       logicalAndExpression ("||" logicalOrExpression)?
-  Node _or() {
-    var left = _and();
-    if (!_scanner.scan(TokenType.or)) return left;
-    return new OrNode(left, _or());
-  }
-
-  /// Parses a logical and:
-  ///
-  ///     logicalAndExpression:
-  ///       simpleExpression ("&&" logicalAndExpression)?
-  Node _and() {
-    var left = _simpleExpression();
-    if (!_scanner.scan(TokenType.and)) return left;
-    return new AndNode(left, _and());
-  }
-
-  /// Parses a simple expression:
-  ///
-  ///     simpleExpression:
-  ///       "!" simpleExpression |
-  ///           "(" conditionalExpression ")" |
-  ///           IDENTIFIER
-  Node _simpleExpression() {
-    var token = _scanner.next();
-    switch (token.type) {
-      case TokenType.not:
-        var child = _simpleExpression();
-        return new NotNode(child, token.span.expand(child.span));
-
-      case TokenType.leftParen:
-        var child = _conditional();
-        if (!_scanner.scan(TokenType.rightParen)) {
-          throw new SourceSpanFormatException(
-              'Expected ")".', _scanner.peek().span);
-        }
-        return child;
-
-      case TokenType.identifier:
-        return new VariableNode(token.name, token.span);
-
-      default:
-        throw new SourceSpanFormatException("Expected expression.", token.span);
-    }
-  }
-}