lib/scripts/require.js

var require,
    define;

(function () {
    var modules = {};
    // Stack of moduleIds currently being built.
    var requireStack = [];
    // Map of module ID -> index into requireStack of modules currently being built.
    var inProgressModules = {};

    function build(module) {
        var factory = module.factory;
        module.exports = {};
        delete module.factory;
        factory(require, module.exports, module);
        return module.exports;
    }

    require = function (id) {
        if (!modules[id]) {
            throw "module " + id + " not found";
        } else if (id in inProgressModules) {
            var cycle = requireStack.slice(inProgressModules[id]).join('->') + '->' + id;
            throw "Cycle in require graph: " + cycle;
        }
        if (modules[id].factory) {
            try {
                inProgressModules[id] = requireStack.length;
                requireStack.push(id);
                return build(modules[id]);
            } finally {
                delete inProgressModules[id];
                requireStack.pop();
            }
        }
        return modules[id].exports;
    };

    define = function (id, factory) {
        if (modules[id]) {
            throw "module " + id + " already defined";
        }

        modules[id] = {
            id: id,
            factory: factory
        };
    };

    define.remove = function (id) {
        delete modules[id];
    };

})();

//Export for use in node
if (typeof module === "object" && typeof require === "function") {
    module.exports.require = require;
    module.exports.define = define;
}