27 Jul
2010
27 Jul
'10
3:58 a.m.
On Jul 27, 2010, at 9:15 AM, Sjoerd Visscher wrote:
Oh, by the way, with noMatch, eps, alt and seq_ RegExp is itself a Semiring,
Yes, but it's hard to define an Eq instance for arbitrary regular expressions that reflects equivalence of regexps. There is currently only `instance Eq (RegExp Char)` which implements structural identity used for the QuickCheck tests.
but I'm not sure what that would do.
I think matching a regular expression against a word in the "regular expressions semiring" returns an unfolding of the original regular expression which matches exactly the given word. Sebastian -- Underestimating the novelty of the future is a time-honored tradition. (D.G.)