This may also be of use. Conversion to numbers (or any other non-text type), sanity-checking, and much more, is covered by this tiny framework (code and sample app included):
It’s as simple as I could make it. Some of it might become a bit simpler if the field gained an official “on-validate” event. (This would serve a multitude of purposes, not just conversion to number format.) Right now, I have to hook all of the field’s existing events to determine when validation should occur.
In a previous test app, I added up- and down-arrow buttons to a text field. Would anyone be interested in that app?