Re: forced coercion

On Thu, Aug 21, 2014 at 09:23:00PM +0000, John Macdonald wrote:
> So, how do I specify a type that starts with a base type, but then applies a coercion?  All the examples I see of coercions have a "natural" base encoding, with the coercion providing a way to take some other type of value and turn it into the base - but when base is a validated string, it is hard to get it to actually use the coercion.

Right, coercions are only applied if the data doesn't already validate
against the type.  So (saying this without puzzling through your lookahead
assertion) you may need to define your new type as a totally separate type
on its own, not derived from the first type, so it doesn't already
validate, and therefore executes the coercion.