bart at cs.pdx.edu
Mon Sep 9 05:27:42 CEST 2013
Ah! Suddenly I understand the weird error messages I've been seeing.
Thanks much for the explanation. --Bart
On Sun, Sep 8, 2013 at 9:29 AM, Henning Thielemann
<schlepptop at henning-thielemann.de> wrote:
> Am 06.09.2013 19:56, schrieb Bart Massey:
>> TypeFamilies are kind of heavy machinery here :-), but since it would
>> be confined to the library and seems to solve the problem, I'd be in
>> favor of doing as you suggest. We can conditionally compile if we are
>> worried about non-GHC implementations, I think. Do other folks have an
>> opinion? --Bart
> The right solution would be to have (>>) :: m () -> m a -> m a.
> With this type GHC could infer the return type from the fact that the result
> of printf is unused.
> However, since it was chosen to be (>>) :: m b -> m a -> m a, we end up with
> follow-up hacks.
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