Re: [Haskell-beginners] Re: Is this overkill?

Chaddaï Fouché wrote:

On Sat, Apr 4, 2009 at 5:20 AM, Zachary Turner wrote:

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With Conal's semantic editor combinators

http://conal.net/blog/posts/semantic-editor-combinators/

it would be written as

trueIndices = (result . result) (map fst . filter snd . zip [0..]) (zipWith (&&))

That was a pretty interesting blog post, and easily understandable which is always nice. Thanks for the link. I also had never even used the zipWith function, so thanks for pointing out that equivalence.

I'm not sure you really want to write this pointfree... Generally I tend to avoid it when there's two arguments of identical standing. Also the (map fst . filter snd...) is a Data.List function (findIndices) :

trueIndices xs ys = findindices id $ zipWith (&&) xs ys

I love the pointfree style and it might be a good exercise to try and transcribe any function to pointfree, but sometimes pointful is just clearer.

Or to put it differently, sometimes "pointfree is pointless" ;-) /M -- Magnus Therning (OpenPGP: 0xAB4DFBA4) magnus＠therning．org Jabber: magnus＠therning．org http://therning.org/magnus identi.ca|twitter: magthe Haskell is an even 'redder' pill than Lisp or Scheme. -- PaulPotts