[Haskell-cafe] Having trouble with zip12..

[Brandon S. Allbery KF8NH]

On 2008 Jul 6, at 16:47, Tony Morris wrote:

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> Michael Feathers wrote:
>> zip12 ((tails . nub) flightPaths) wayPoints etopsPackets (hd
>> geoCaches) groundSpeeds headings (map windShift headings)
>> (regulations !! 2) (foldr (\|/) (tail pathDistances)) [ghy x | x <-
>> [1..], full x] (nub . nub) arrivalSchedule
>
> Hi Michael,
> Sorry to distract from your issue, but I note that (nub . nub) can be
> replaced with just 'nub' since the function nub is idempotent (f . f
> == f).


Or even better, with a custom nub:  in order to handle some special  
cases the Prelude nub is rather inefficient.

-- 
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university    KF8NH