PHP5或替代品中沙盒的建议？

I've been slowly working on a personnel project to run a webmud like game using extjs as my frontend. One of the design choices I made was to allow user-generated evaluated code for game logic. So when the player enters a new "room" a number of state scripts would be called along the lines of "has player been here before, should they be here, do they have x inventory item" and then respond accordingly. Furthermore basic room "actions" would be hard coded ( go N/S/E/W ) but advanced actions would be available as the same user-generated evaluated scripts.I've been slowly working on a personnel project