com.google.gwt.dev.js.ast.JsPrefixOperation Maven / Gradle / Ivy
/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* 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.gwt.dev.js.ast;
import com.google.gwt.dev.jjs.SourceInfo;
/**
* A JavaScript prefix operation.
*/
public final class JsPrefixOperation extends JsUnaryOperation implements CanBooleanEval {
public JsPrefixOperation(SourceInfo sourceInfo, JsUnaryOperator op) {
this(sourceInfo, op, null);
}
public JsPrefixOperation(SourceInfo sourceInfo, JsUnaryOperator op, JsExpression arg) {
super(sourceInfo, op, arg);
}
@Override
public NodeKind getKind() {
return NodeKind.PREFIX_OP;
}
@Override
public boolean isBooleanFalse() {
if (getOperator() == JsUnaryOperator.VOID) {
return true;
}
if (getOperator() == JsUnaryOperator.NOT && getArg() instanceof CanBooleanEval) {
CanBooleanEval eval = (CanBooleanEval) getArg();
return eval.isBooleanTrue();
}
return false;
}
@Override
public boolean isBooleanTrue() {
if (getOperator() == JsUnaryOperator.NOT && getArg() instanceof CanBooleanEval) {
CanBooleanEval eval = (CanBooleanEval) getArg();
return eval.isBooleanFalse();
}
if (getOperator() == JsUnaryOperator.TYPEOF) {
return true;
}
return false;
}
@Override
public boolean isDefinitelyNotNull() {
if (getOperator() == JsUnaryOperator.TYPEOF) {
return true;
}
return getOperator() != JsUnaryOperator.VOID;
}
@Override
public boolean isDefinitelyNull() {
return getOperator() == JsUnaryOperator.VOID;
}
@Override
public void traverse(JsVisitor v, JsContext ctx) {
if (v.visit(this, ctx)) {
super.traverse(v, ctx);
}
v.endVisit(this, ctx);
}
}