[Haskell-cafe] Code Golf

[Sjoerd Visscher]

This is one with functional lists:

diag = foldr1 (zipWith (.) $. id ~> (id:) ~> id)
      $. map (++ repeat id) ~> takeWhile (not.null.($[]))
      $. (map.map) (:) ~> ($[]) . mconcat

On Apr 20, 2009, at 1:48 PM, Sebastian Fischer wrote:

>
> On Apr 18, 2009, at 2:48 AM, Sjoerd Visscher wrote:
>
>> using Matt Hellige's pointless fun
>> http://matt.immute.net/content/pointless-fun
>>
>> diag = foldr1 (zipWith (++) $. id ~> ([]:) ~> id)
>>    $. map (++ repeat []) ~> takeWhile (not.null)
>>    $. (map.map) (:[]) ~> concat
>
> pretty! Those seem to be exactly the combinators that I was looking  
> for.
>
> Unfortunately, I still don't manage to mimic my version that uses  
> functional lists and continuations (but no ++) mainly because I'm  
> lacking an equivalent of the second line of the above solution which  
> allows for the simpler 'zipWith (++)' instead of the merge function.
>
> Anyway, once you know what they mean, Matt's combinators are quite  
> useful. Thanks for pointing that out!
>
> Cheers,
> Sebastian
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--
Sjoerd Visscher
sjoerd at w3future.com