Constant evaluation support

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/constant/DartObject.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/constant/DartObject.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/constant/DartObject.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/constant/DartObject.java
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+/*
+ * Copyright (c) 2013, the Dart project authors.
+ * 
+ * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * 
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.google.dart.engine.constant;
+
+import com.google.dart.engine.type.InterfaceType;
+
+import java.math.BigInteger;
+
+/**
+ * The interface {@code DartObject} defines the behavior of objects that represent the state of a
+ * Dart object.
+ */
+public interface DartObject {
+  /**
+   * Return the boolean value of this object, or {@code null} if either the value of this object is
+   * not known or this object is not of type 'bool'.
+   * 
+   * @return the boolean value of this object
+   */
+  public Object getBoolValue();
+
+  /**
+   * Return the floating point value of this object, or {@code null} if either the value of this
+   * object is not known or this object is not of type 'double'.
+   * 
+   * @return the floating point value of this object
+   */
+  public Double getDoubleValue();
+
+  /**
+   * Return the integer value of this object, or {@code null} if either the value of this object is
+   * not known or this object is not of type 'int'.
+   * 
+   * @return the integer value of this object
+   */
+  public BigInteger getIntValue();
+
+  /**
+   * Return the string value of this object, or {@code null} if either the value of this object is
+   * not known or this object is not of type 'String'.
+   * 
+   * @return the string value of this object
+   */
+  public String getStringValue();
+
+  /**
+   * Return the run-time type of this object.
+   * 
+   * @return the run-time type of this object
+   */
+  public InterfaceType getType();
+
+  /**
+   * Return {@code true} if this object represents the value 'false'.
+   * 
+   * @return {@code true} if this object represents the value 'false'
+   */
+  public boolean isFalse();
+
+  /**
+   * Return {@code true} if this object represents the value 'null'.
+   * 
+   * @return {@code true} if this object represents the value 'null'
+   */
+  public boolean isNull();
+
+  /**
+   * Return {@code true} if this object represents the value 'true'.
+   * 
+   * @return {@code true} if this object represents the value 'true'
+   */
+  public boolean isTrue();
+}