[GHC] #15622: Generalize `E{0,1,2,3,6,9,12}` from `Data.Fixed`

GHC ghc-devs at haskell.org
Tue Oct 9 00:19:02 UTC 2018


#15622: Generalize `E{0,1,2,3,6,9,12}` from `Data.Fixed`
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        Reporter:  rockbmb           |                Owner:  rockbmb
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Core Libraries    |              Version:  8.4.3
      Resolution:                    |             Keywords:  base,
                                     |  Data.Fixed
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by rockbmb):

 Replying to [comment:19 Bodigrim]:
 > Actually, we can generalise the current approach to any base:
 > {{{#!hs
 > data E (n :: Nat)
 >
 > instance KnownNat n => HasResolution (E n) where
 >     resolution = natVal . Compose
 >
 > type Milli = E 1000
 > }}}

 How would the `Compose` help with numeric bases here?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15622#comment:20>
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