Support unary minus operator (issue 3767)

compiler/java/com/google/dart/compiler/parser/DartParser.java

 // Copyright (c) 2012, 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.
 
 package com.google.dart.compiler.parser;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.io.CharStreams;
 import com.google.dart.compiler.DartCompilationError;
@@ skipping 1441 matching lines @@
     if (modifiers.isFactory()) {
       if (modifiers.isAbstract()) {
         reportError(position(), ParserErrorCode.FACTORY_CANNOT_BE_ABSTRACT);
       }
       if (modifiers.isStatic()) {
         reportError(position(), ParserErrorCode.FACTORY_CANNOT_BE_STATIC);
       }
     }
 
     int arity = -1;
+    Token operation = null;
     if (peek(1) != Token.LPAREN && optionalPseudoKeyword(OPERATOR_KEYWORD)) {
       // Overloaded operator.
       if (modifiers.isStatic()) {
         reportError(position(), ParserErrorCode.OPERATOR_CANNOT_BE_STATIC);
       }
       modifiers = modifiers.makeOperator();
 
       beginOperatorName();
-      Token operation = next();
+      operation = next();
       if (operation.isUserDefinableOperator()) {
         name = done(new DartIdentifier(operation.getSyntax()));
         if (operation == Token.ASSIGN_INDEX) {
           arity = 2;
+        } else if (operation == Token.SUB) {
+          arity = -1;
         } else if (operation.isBinaryOperator()) {
           arity = 1;
         } else if (operation == Token.INDEX) {
           arity = 1;
         } else {
           assert operation.isUnaryOperator();
           arity = 0;
         }
       } else if (operation == Token.IDENTIFIER
                  && ctx.getTokenString().equals(CALL_KEYWORD)) {
@@ skipping 79 matching lines @@
     if (arity != -1) {
       if (parameters.size() != arity) {
         reportError(position(), ParserErrorCode.ILLEGAL_NUMBER_OF_PARAMETERS);
       }
       // In methods with required arity each parameter is required.
       for (DartParameter parameter : parameters) {
         if (parameter.getModifiers().isNamed()) {
           reportError(parameter, ParserErrorCode.NAMED_PARAMETER_NOT_ALLOWED);
         }
       }
+    } else if (operation == Token.SUB) {
+      if (parameters.size() != 0 && parameters.size() != 1) {
+        reportError(position(), ParserErrorCode.ILLEGAL_NUMBER_OF_PARAMETERS);
+      }
+      // In methods with required arity each parameter is required.
+      for (DartParameter parameter : parameters) {
+        if (parameter.getModifiers().isNamed()) {
+          reportError(parameter, ParserErrorCode.NAMED_PARAMETER_NOT_ALLOWED);
+        }
+      }
     }
 
     // Parse initializer expressions for constructors.
     List<DartInitializer> initializers = new ArrayList<DartInitializer>();
     if (match(Token.COLON) && !(isParsingInterface || modifiers.isFactory())) {
       parseInitializers(initializers);
       boolean isRedirectedConstructor = validateInitializers(parameters, initializers);
       if (isRedirectedConstructor) {
         modifiers = modifiers.makeRedirectedConstructor();
       }
@@ skipping 3276 matching lines @@
   private void reportError(DartNode node, ErrorCode errorCode, Object... arguments) {
     if (node != null) {
       reportError(new DartCompilationError(node, errorCode, arguments));
     }
   }
 
   private boolean currentlyParsingToplevel() {
     return   !(isParsingInterface || isTopLevelAbstract || isParsingClass);
   }
 }