[Haskell-cafe] Proposal: (.:) operator in base.

[Alexander Berntsen]

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On 18/08/16 23:57, Mike Ledger wrote:
> IMO: I've never seen a compelling use of this; I think it decreases
> clarity, and barely shaves off any characters from equivalent "pointful"
> expressions.

I think it quite compelling. An example:

asSeconds :: Hour h -> Minute m -> Second s -> Second t
- -- | asSeconds take some 'TimeUnit's and convert them to 'Second's.
asSeconds h m s = MkSecond $ 3600 * timeVal h + 60 * timeVal m + timeVal s

hmsToDiffTime :: Hour h -> Minute m -> Second s -> DiffTime
- -- | 'hmsToDiffTime' converts time of day in hours, minutes and seconds to the
- -- time from midnight as a 'DiffTime'.
hmsToDiffTime = (secondsToDiffTime . timeVal) .:. asSeconds


As for putting it in base -- meh. I use the composition package, or
define it myself. So I agree with Oleg; -1.
- -- 
Alexander
alexander at plaimi.net
https://secure.plaimi.net/~alexander
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