/*
 * Name: Mike Cifelli
 * Course: CIS 443 - Programming Languages
 * Assignment: Lisp Interpreter 2
 */

package eval;

import parser.*;

/**
 * This class represents a Lisp FUNCTION in the PL-Lisp implementation.
 */
public class LambdaExpression extends SExpression {

    private Cons lexpr;
    private UDFunction function;

    /**
     * Create a new FUNCTION with the specified lambda expression and
     * internal representation.
     *
     * @param lexpr
     *  the lambda expression of this FUNCTION
     * @param function
     *  the internal representation of this FUNCTION
     */
    public LambdaExpression(Cons lexpr, UDFunction function) {
        this.lexpr = lexpr;
        this.function = function;
    }

    /**
     * Test if this S-expression is a FUNCTION.
     *
     * @return
     *  <code>true</code>
     */
    public boolean functionp() {
        return true;
    }

    /**
     * Retrieve the lambda expression of this FUNCTION.
     *
     * @return
     *  the lambda expression of this FUNCTION
     */
    public Cons getLExpression() {
        return lexpr;
    }

    /**
     * Retrieve the internal representation of this FUNCTION.
     *
     * @return
     *  the user-defined function of this FUNCTION
     */
    public UDFunction getFunction() {
        return function;
    }

    /**
     * Returns a string representation of this FUNCTION.
     *
     * @return
     *  a string representation of this FUNCTION
     */
    public String toString() {
        return lexpr.toString();
    }

}