The proposal received support from two people, and got no objection, so I
created a ticket for it on the GHC trac.
https://ghc.haskell.org/trac/ghc/ticket/8595
Thank you,
Takano Akio
On Wed, Nov 20, 2013 at 4:40 PM, Akio Takano
Hi,
Currently mapMaybe does not fuse at all. The attached patch implements necessary rules for fold/build fusion in both sides (the result and the second argument) to happen. When fusion does not happen, the function should behave exactly the same as before.
I ran some benchmarks, testing cases where fusion does and does not happen:
http://htmlpreview.github.io/?https://github.com/takano-akio/mapmaybe-benchm...
The benchmark code is:
https://github.com/takano-akio/mapmaybe-benchmarks/blob/master/main.hs
Discussion period: 2 weeks.
Thank you, Takano Akio