/*
 * Copyright 2012 Canonical Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; version 3.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

.pragma library
// By defining Stack as a function, we can make its variables private,
// and force calls to Stack to make use of the functions we define.
function Stack() {
    var elements;
    this.clear = function() {
        elements = [];
    }

    this.clear();

    this.push = function(element) {
        elements.push(element);
    };

    this.pop = function() {
        elements.pop();
    };

    this.size = function() {
        return elements.length;
    }

    this.top = function() {
        if (this.size() < 1) return undefined;
        return elements[elements.length-1];
    }
}

function createStack() {
    return new Stack();
}
