Limit arg length

[ephetic]

For Array conditions (i.e. argument checking), look into only passing as many arguments to fn as the length of the argument pattern, i.e. fn.apply(null, args.slice(0, cond.length).

This might be useful for when m functions are passed as callbacks to things that pass extra arguments. Wait, no; it's patterns will have to match those arguments. How about when the m function is given a callback as fn that expects an unknownish number of args. Yeah, maybe.

If nothing else, it would make it more predictable.