Note: I'm not sure these first two items are necessary
- Improve the error handling (only warn once per call, anyway).
- Benchmark & optimise if necessary
(i.e. don't get the cx multiple times)
But these two are definitely worth looking into:
- See what happens from FETCH/STORE routines (eek!)
- NUMBER, INTEGER (and STRING?) contexts. This will involve
constructing a large and tedious table of ops indicating which
args are treated as which sort of value.