[GHC] #11314: Documentation on const function is wrong

[GHC]

#11314: Documentation on const function is wrong
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        Reporter:  milleniumbug      |                Owner:
            Type:  bug               |               Status:  patch
        Priority:  low               |            Milestone:  8.0.1
       Component:  libraries/base    |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Documentation     |  Unknown/Multiple
  bug                                |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D1720
       Wiki Page:                    |
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Changes (by bgamari):

 * status:  new => patch
 * failure:  None/Unknown => Documentation bug
 * differential:   => Phab:D1720
 * milestone:   => 8.0.1


Old description:

> It currently only says
>
>     Constant function
>
> which is not only not informative (how am I supposed to use this
> function, some API examples would be nice), but actually wrong (`const`
> is not a constant function, `const x` is)
>
> I suggest the following wording instead:
>
>     Returns a unary constant function (a function that returns the same
> value for all inputs) from the argument @a at .

New description:

 It currently only says

 > Constant function

 which is not only not informative (how am I supposed to use this function,
 some API examples would be nice), but actually wrong (`const` is not a
 constant function, `const x` is)

 I suggest the following wording instead:

 > Returns a unary constant function (a function that returns the same
 value for all inputs) from the argument @a at .

--

Comment:

 Indeed, this is one of many examples where our documentation is sorely
 lacking. How does Phab:D1720 look?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11314#comment:1>
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