[GHC] #4385: Type-level natural numbers

[GHC]

#4385: Type-level natural numbers
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        Reporter:  diatchki                 |            Owner:  diatchki
            Type:  feature request          |           Status:  new
        Priority:  normal                   |        Milestone:  7.6.2
       Component:  Compiler (Type checker)  |          Version:
      Resolution:                           |         Keywords:
Operating System:  Unknown/Multiple         |     Architecture:
 Type of failure:  None/Unknown             |  Unknown/Multiple
       Test Case:                           |       Difficulty:  Unknown
        Blocking:                           |       Blocked By:
                                            |  Related Tickets:
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Comment (by Lemming):

 Replying to [comment:67 hvr]:
 > Replying to [comment:66 Lemming]:
 > > Type-level natural numbers are advertised everywhere for GHC-7.8, but
 I cannot find documentation in
 > >   http://www.haskell.org/ghc/docs/7.8.1-rc2/html/users_guide/
 >
 > does
 http://www.haskell.org/ghc/docs/7.8.1-rc2/html/users_guide/promotion.html
 #promoted-literals count?

 Indeed, that's a nice start. What about type-level natural number
 operations and predicates? What about conversion from type-level numbers
 to data-level numbers? I found:
   https://ghc.haskell.org/trac/ghc/wiki/TypeNats/Basics
   https://ghc.haskell.org/trac/ghc/wiki/TypeNats/Operations
 Do these articles reflect the current state of implementation?

 I also found the announcement:
   http://www.well-typed.com/blog/85
 where many feature names are linked to the GHC documentation, but "type-
 level natural numbers" is not. I also like to see the keyword "type-level
 natural number" somewhere in GHC docs, since this is how this feature is
 advertised.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4385#comment:68>
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