[Haskell-beginners] Re: Is this overkill?

Magnus Therning magnus at therning.org
Sun Apr 5 12:08:20 EDT 2009

Chaddaï Fouché wrote:
> On Sat, Apr 4, 2009 at 5:20 AM, Zachary Turner <divisortheory at gmail.com> wrote:
>>> 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" ;-)


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

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