Hello,
-1 for me too, for the reasons already discussed in the thread (i.e.,
because it makes it easy to accidentally ignore potentially important
results). I think that gains in readability from this generalization are
at best questionable.
-Iavor
On Tue, Jun 5, 2012 at 2:07 PM, Andres Löh
Btw. the mapM memory leak can be easily and accidentally resurrected by writing
when_ b (mapM f xs)
with
f :: a -> m () when_ :: Bool -> m a -> m ()
I don't understand the whole mapM analogy (yet). I don't need when_ to get into trouble with using mapM. Also, whether a space leak with mapM arises or not typically doesn't depend on whether you use its result or not. It's the other way round: if you run mapM on a huge list but aren't interested in the results, then you should use mapM_ instead. So the problem here is accidentally producing a (large) result rather than accidentally ignoring it.
Cheers, Andres
-- Andres Löh, Haskell Consultant Well-Typed LLP, http://www.well-typed.com
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