org.mozilla.javascript.ast.UnaryExpression Maven / Gradle / Ivy
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/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.javascript.ast;
import org.mozilla.javascript.Token;
/**
* AST node representing unary operators such as {@code ++},
* {@code ~}, {@code typeof} and {@code delete}. The type field
* is set to the appropriate Token type for the operator. The node length spans
* from the operator to the end of the operand (for prefix operators) or from
* the start of the operand to the operator (for postfix).
*
* The {@code default xml namespace = <expr>} statement in E4X
* (JavaScript 1.6) is represented as a {@code UnaryExpression} of node
* type {@link Token#DEFAULTNAMESPACE}, wrapped with an
* {@link ExpressionStatement}.
*/
public class UnaryExpression extends AstNode {
private AstNode operand;
private boolean isPostfix;
public UnaryExpression() {
}
public UnaryExpression(int pos) {
super(pos);
}
/**
* Constructs a new postfix UnaryExpression
*/
public UnaryExpression(int pos, int len) {
super(pos, len);
}
/**
* Constructs a new prefix UnaryExpression.
*/
public UnaryExpression(int operator, int operatorPosition,
AstNode operand) {
this(operator, operatorPosition, operand, false);
}
/**
* Constructs a new UnaryExpression with the specified operator
* and operand. It sets the parent of the operand, and sets its own bounds
* to encompass the operator and operand.
* @param operator the node type
* @param operatorPosition the absolute position of the operator.
* @param operand the operand expression
* @param postFix true if the operator follows the operand. Int
* @throws IllegalArgumentException} if {@code operand} is {@code null}
*/
public UnaryExpression(int operator, int operatorPosition,
AstNode operand, boolean postFix) {
assertNotNull(operand);
int beg = postFix ? operand.getPosition() : operatorPosition;
// JavaScript only has ++ and -- postfix operators, so length is 2
int end = postFix
? operatorPosition + 2
: operand.getPosition() + operand.getLength();
setBounds(beg, end);
setOperator(operator);
setOperand(operand);
isPostfix = postFix;
}
/**
* Returns operator token – alias for {@link #getType}
*/
public int getOperator() {
return type;
}
/**
* Sets operator – same as {@link #setType}, but throws an
* exception if the operator is invalid
* @throws IllegalArgumentException if operator is not a valid
* Token code
*/
public void setOperator(int operator) {
if (!Token.isValidToken(operator))
throw new IllegalArgumentException("Invalid token: " + operator);
setType(operator);
}
public AstNode getOperand() {
return operand;
}
/**
* Sets the operand, and sets its parent to be this node.
* @throws IllegalArgumentException} if {@code operand} is {@code null}
*/
public void setOperand(AstNode operand) {
assertNotNull(operand);
this.operand = operand;
operand.setParent(this);
}
/**
* Returns whether the operator is postfix
*/
public boolean isPostfix() {
return isPostfix;
}
/**
* Returns whether the operator is prefix
*/
public boolean isPrefix() {
return !isPostfix;
}
/**
* Sets whether the operator is postfix
*/
public void setIsPostfix(boolean isPostfix) {
this.isPostfix = isPostfix;
}
@Override
public String toSource(int depth) {
StringBuilder sb = new StringBuilder();
sb.append(makeIndent(depth));
int type = getType();
if (!isPostfix) {
sb.append(operatorToString(type));
if (type == Token.TYPEOF || type == Token.DELPROP || type == Token.VOID) {
sb.append(" ");
}
}
sb.append(operand.toSource());
if (isPostfix) {
sb.append(operatorToString(type));
}
return sb.toString();
}
/**
* Visits this node, then the operand.
*/
@Override
public void visit(NodeVisitor v) {
if (v.visit(this)) {
operand.visit(v);
}
}
}