Haskell Platform Proposal: HLint

Neil Mitchell ndmitchell at gmail.com
Wed Nov 24 19:42:02 EST 2010

>> If you aren't using a boilerplate removal library, and are working
>> with haskell-src-exts, then you are very probably doing it wrong!
> Oh?  Why is that?

By wrong I don't mean "incorrect results", I mean hideously ugly. Take
the example of stripping out all type signatures in patterns, since
you want to get rid of that extension. Without a boilerplate removal
library that would take ~100 lines of code, perhaps more, and be very
sensitive to which extensions your parser supported. With Uniplate I
can write:

import Data.Generics.Uniplate.Data
removePatternSigs = transformBi f
        f (PatTypeSig _ x _) = x
        f x = x

If I didn't use Uniplate, I'd find the extra syntax extensions in HSE
to be very annoying. Since I do use Uniplate, I only need to think
about them when I'm working with them - so I transparently support
them, and when I do need them, they're already there. I'm using
Uniplate as an example since I think it's the nicest boilerplate
removal library, but I'm biased, and any boilerplate removal library
should be able to do similar tricks.

Thanks, Neil

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