This is the sort of thing that trace-based optimisation can help with. It's able to observe that the value bound to chr doesn't change between invocations and i

This is the sort of thing that trace-based optimisation can help with. It's able to observe that the value bound to chr doesn't change between invocations and inline the lookup accordingly. I believe Mark Shannon's HotPy runtime (http://www.dcs.gla.ac.uk/~marks/ http://www.dcs.gla.ac.uk/~marks/) attempts to do this.