[Haskell-cafe] mixing map and mapM ?

briand at aracnet.com briand at aracnet.com
Thu May 6 09:19:49 EDT 2010


On Thu, 06 May 2010 12:00:01 +0100
Neil Brown <nccb2 at kent.ac.uk> wrote:


> At which point I prefer Ivan's liftM version rather than the above 
> section (or worse: using (<$>) prefix).  The original request is a 
> relatively common thing to want to do, so I was slightly surprised
> that hoogling for:
> 
> (b -> c) -> (a -> f b) -> a -> f c
> 
> didn't turn up any relevant results.  This function is a lot like
> (<=<) but with a pure rather than side-effecting function on the
> left-hand side.
> 

ha ! I had actually remembered to hoogle :-) and didn't get anything
either, only I wasn't sure I put the signature in correctly.

Brian



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