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

package parser;

/**
 * This class represents a NUMBER in the PL-Lisp implementation.
 */
public class LispNumber extends Atom {

    private int value;

    /**
     * Create a new NUMBER with the specified text.
     *
     * @param text
     *  the text representing this NUMBER
     * @throws IllegalArgumentException
     *  Indicates that <code>text</code> does not represent a valid integer.
     */
    public LispNumber(String text) {
        super(text.replaceFirst("^0+(?!$)", ""));

        try {
            this.value = Integer.parseInt(text);
        } catch (NumberFormatException e) {
            throw new IllegalArgumentException(text +
                                               " is not a valid integer");
        }
    }

    /**
     * Create a new NUMBER with the specified value.
     *
     * @param value
     *  the integer value of this NUMBER
     */
    public LispNumber(int value) {
        super(Integer.toString(value));

        this.value = value;
    }

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

    /**
     * Retrieve the integer value of this NUMBER.
     *
     * @return
     *  the integer value of this NUMBER
     */
    public int getValue() {
        return value;
    }

}