/*
 * Name: Mike Cifelli
 * Course: CIS 443 - Programming Languages
 * Assignment: Lisp Interpreter 1
 */

package eval;

import parser.*;

/**
 * <code>QUOTE</code> represents the QUOTE form in Lisp.
 */
public class QUOTE extends LispFunction {

    // The number of arguments that QUOTE takes.
    private static final int NUM_ARGS = 1;

    public SExpression call(Cons argList) {
        // retrieve the number of arguments passed to QUOTE
        int argListLength = LENGTH.getLength(argList);

        // make sure we have received exactly one argument
        if (argListLength != NUM_ARGS) {
            Cons originalSExpr = new Cons(new Symbol("QUOTE"), argList);
            String errMsg = "too " +
                            ((argListLength > NUM_ARGS) ? "many" : "few") +
                            " arguments given to QUOTE: " + originalSExpr;

            throw new RuntimeException(errMsg);
        }

        return argList.getCar();
    }

    /**
     * Determine if the arguments passed to this Lisp function should be
     * evaluated.
     *
     * @return
     *  <code>false</code>
     */
    public boolean evaluateArguments() {
        return false;
    }

}