code: function getModule(parent, id) {
  		if ('require' === id || 'exports' === id || 'module' === id) {
  			return { id:id, loaded:true, exports:parent[id] || parent, children:[] };
  		}
  
  		id = resolve(parent, id).replace(/\.js$/i, '');
  		if (modules[id]) { return modules[id]; }
  		var uri = canonicalize(urls[id] ? urls[id] : path.replace(/[^\/]*$/, id + '.js')),
  			module = (modules[id] = { id:id, filename:uri, uri:uri, loaded:false, children:[] });
  		module.require = makeRequire(module);
  		waits[id] = [];
  		return module;
  	}
docs: build or retrieve a specific module object