Hello,
I want to use the RULES pragma and cannot get my rules to fire. Here is a
simplified example of what I'm trying.
I define my own version of foldMap for lists:
fold :: Monoid m = (a - m) - [a] - m
fold f = foldr mappend mempty . map f
-- alternative, trying to avoid
On Wednesday 09 February 2011 16:23:15, Sebastian Fischer wrote:
Why don't the rules fire, what can I change such that they do, and what
to get rid of the warning for the second rule (which I think is the one
I should use)?
Didn't spot that, sorry.
Best regards,
Sebastian
Here is the
On Wednesday 09 February 2011 16:23:15, Sebastian Fischer wrote:
Why don't the rules fire,
Because the 'match' is at the wrong type. In main, idGen appears as
idGen_anJ :: ([()] - [[()]]) - [[()]] - [[()]]
at some point (yay for ghc -v4), so it doesn't match g's polymorphic type.
what can I
Why don't the rules fire,
Because the 'match' is at the wrong type.
This was the correct hint, thanks!
what can I change such that they do,
Type signatures.
Initially, I thought that just leaving out the polymorphic signature should
fix the problem. But I think it cannot be fixed by
