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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 for let statements and expressions. Node type is {@link Token#LET} or {@link
 * Token#LETEXPR}.
 *
 *  LetStatement:
 *     let ( VariableDeclarationList ) Block
 * LetExpression:
 *     let ( VariableDeclarationList ) Expression
 *
 * 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}.
 */
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.)
     *
     * 
     *
     * @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);
            }
        }
    }
}