Don't use TransformListComp ?? -- Don ndmitchell:

Hi,

The TransformListComp extension makes group a keyword. Unfortunately group is a useful function, and is even in Data.List. Thus, Data.List.group and TransformListComp are incompatible. This seems a very painful concession to give up a nice function name for a new extension. Is this intentional? Here's an example:

...

$ cat GroupKeyword.hs {-# LANGUAGE TransformListComp #-} module GroupKeyword where

a = map head $ group $ sort [1..100] $ ghci GroupKeyword.hs GHCi, version 6.10.2: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer ... linking ... done. Loading package base ... linking ... done. [1 of 1] Compiling GroupKeyword ( GroupKeyword.hs, interpreted )

GroupKeyword.hs:4:15: parse error on input `group' Failed, modules loaded: none. Prelude>

There are some places I'd like to use TransformListComp, but I often want to use group in the same module.

Thanks

Neil _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

Hi, I agree this is annoying. It was hard to find syntax which was both meaningful and currently unused, so we settled on this instead. As Simon says, suggestions are welcome! Note that group *should* be parsed as a special id, so you can still import D.L qualified and then use dot notation to access the function. Cheers, Max 2009/6/21 Neil Mitchell :

Hi,

The TransformListComp extension makes group a keyword. Unfortunately group is a useful function, and is even in Data.List. Thus, Data.List.group and TransformListComp are incompatible. This seems a very painful concession to give up a nice function name for a new extension. Is this intentional? Here's an example:

...

$ cat GroupKeyword.hs {-# LANGUAGE TransformListComp #-} module GroupKeyword where

a = map head $ group $ sort [1..100] $ ghci GroupKeyword.hs GHCi, version 6.10.2: http://www.haskell.org/ghc/  :? for help Loading package ghc-prim ... linking ... done. Loading package integer ... linking ... done. Loading package base ... linking ... done. [1 of 1] Compiling GroupKeyword     ( GroupKeyword.hs, interpreted )

GroupKeyword.hs:4:15: parse error on input `group' Failed, modules loaded: none. Prelude>

There are some places I'd like to use TransformListComp, but I often want to use group in the same module.

Thanks

Neil