This is a bit more heavy-handed than I might like, but it does appear to
do the right things:
* accepts numeric input appropriately, truncating floats
* matches string input against a regex, then coerces number-looking
strings to int
* makes a best effort to coerce anything else to a string, then subjects
it to the same treatment
* raises an error in the event of incorrect number of arguments or
non-number-looking strings
I've also included some additional unit tests.
No more coercing to String and regex matching. Instead, we now coerce
to Integer at the beginning or raise an error if we cannot coerce to
Integer.
A consequence of this change is that the function will now accept
blatantly non-numeric strings as input, and return false. This seems a
bit goofy to me, but it's how String#to_i works. If we really don't
like this, then I'm open to suggestions.
