Re: [Haskell-cafe] Guards on variable bindings

24 Jan 2022


      That seems fine to me because they can be combined into a single
case-of. I just don't see how you'd do so with an unguarded clause;
guess I'd have to look at -ddump-ds to see what exactly it's doing
with them,

On Mon, Jan 24, 2022 at 4:29 PM Tom Ellis
 wrote:
...
I don't think that can be the reason.  It is possible to have a single
clause with multiple guards:
bar | False = ()
        | True = ()
It's just not possible to have multiple clauses if one of them is
guarded, apparently.
On Mon, Jan 24, 2022 at 04:24:43PM -0500, Brandon Allbery wrote:
...
I think because it desugars to a case-of and there's nothing to case
on in the first one?
On Mon, Jan 24, 2022 at 4:18 PM Tom Ellis
 wrote:
...
According to GHC there are multiple declarations of bar, but not of
foo.  I don't understand.  Why is it not valid to have multiple
clauses for a variable binding?
Tom
bar | False = ()
    bar = ()
foo _ | False = ()
    foo _ = ()

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-- 
brandon s allbery kf8nh
allbery.b@gmail.com