/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Rhino code, released
 * May 6, 1999.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1997-1999
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Steve Yegge
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License Version 2 or later (the "GPL"), in which
 * case the provisions of the GPL are applicable instead of those above. If
 * you wish to allow use of your version of this file only under the terms of
 * the GPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replacing
 * them with the notice and other provisions required by the GPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the GPL.
 *
 * ***** END LICENSE BLOCK ***** */

package org.mozilla.javascript.ast;

import org.mozilla.javascript.Token;

/**
 * AST node for let statements and expressions.
 * Node type is {@link Token#LET} or {@link Token#LETEXPR}.<p>
 *
 * <pre> <i>LetStatement</i>:
 *     <b>let</b> ( VariableDeclarationList ) Block
 * <i>LetExpression</i>:
 *     <b>let</b> ( VariableDeclarationList ) Expression</pre>
 *
 * Note that standalone let-statements with no parens or body block,
 * such as {@code let x=6, y=7;}, are represented as a
 * {@link VariableDeclaration} node of type {@code Token.LET},
 * wrapped with an {@link ExpressionStatement}.<p>
 */
public class LetNode extends Scope {

    private VariableDeclaration variables;
    private AstNode body;
    private int lp = -1;
    private int rp = -1;

    {
        type = Token.LETEXPR;
    }

    public LetNode() {
    }

    public LetNode(int pos) {
        super(pos);
    }

    public LetNode(int pos, int len) {
        super(pos, len);
    }

    /**
     * Returns variable list
     */
    public VariableDeclaration getVariables() {
        return variables;
    }

    /**
     * Sets variable list.  Sets list parent to this node.
     * @throws IllegalArgumentException if variables is {@code null}
     */
    public void setVariables(VariableDeclaration variables) {
        assertNotNull(variables);
        this.variables = variables;
        variables.setParent(this);
    }

    /**
     * Returns body statement or expression.  Body is {@code null} if the
     * form of the let statement is similar to a VariableDeclaration, with no
     * curly-brace.  (This form is used to define let-bound variables in the
     * scope of the current block.)<p>
     *
     * @return the body form
     */
    public AstNode getBody() {
        return body;
    }

    /**
     * Sets body statement or expression.  Also sets the body parent to this
     * node.
     * @param body the body statement or expression.  May be
     * {@code null}.
     */
    public void setBody(AstNode body) {
        this.body = body;
        if (body != null)
            body.setParent(this);
    }

    /**
     * Returns left paren position, -1 if missing
     */
    public int getLp() {
        return lp;
    }

    /**
     * Sets left paren position
     */
    public void setLp(int lp) {
        this.lp = lp;
    }

    /**
     * Returns right paren position, -1 if missing
     */
    public int getRp() {
        return rp;
    }

    /**
     * Sets right paren position
     */
    public void setRp(int rp) {
        this.rp = rp;
    }

    /**
     * Sets both paren positions
     */
    public void setParens(int lp, int rp) {
        this.lp = lp;
        this.rp = rp;
    }

    @Override
    public String toSource(int depth) {
        String pad = makeIndent(depth);
        StringBuilder sb = new StringBuilder();
        sb.append(pad);
        sb.append("let (");
        printList(variables.getVariables(), sb);
        sb.append(") ");
        if (body != null) {
            sb.append(body.toSource(depth));
        }
        return sb.toString();
    }

    /**
     * Visits this node, the variable list, and if present, the body
     * expression or statement.
     */
    @Override
    public void visit(NodeVisitor v) {
        if (v.visit(this)) {
            variables.visit(v);
            if (body != null) {
                body.visit(v);
            }
        }
    }
}