FW: Pattern guards vs. case (was, unfortunately :Re: interesting
example of laziness/ghc optimisation)
Thu, 1 Mar 2001 03:21:54 -0800
| * * * Ketil Malde <email@example.com> wrote:
| > ut - the converse is not true, is it? I can write
| > ... = case foo of
| > (Foo f) -> ...
| > (Bar b) -> ...
| > ut I can't express that as a pattern-guarded expression, can I?
Check out http://research.microsoft.com/~simonpj/Haskell/guards.html
which is implemented in GHC. Thus
f x | Foo a <- x = ...
| Bar b <- x = ...