On Fri, Sep 16, 2005 at 11:14:14PM -0700, Jason Dagit wrote:
This reminds me that several times now I've wished that Bool was some sort of interface instead of a type. Perhaps Bool could be a type class? I also wish that "if" were a function, but that's probably just the lisper in me speaking. Something like:
See my Boolean.Algebra module. it lets you declare types to be boolean algebras (or lift an arbitrary type to such an algebra) and provides a lot of useful functions on them. although, it sometimes feels like it should be a general lattice class. http://repetae.net/john/recent/out/Boolean.html darcs repo: http://repetae.net/john/repos/Boolean some examples of where I have used this are. in ginsu you can have filters to choose which messages to see. I just created the basic regex filter and lifted it to a full boolean alegbra on them with Boolean.Boolean. In jhc I accumulate various properties of programs with generic routines that accumulate arbitrary types of class boolean. "fuzzy" booleans implemented as doubles have found their way into some projects. and some other places... John -- John Meacham - ⑆repetae.net⑆john⑈