[GHC] #393: functions without implementations

[GHC]

#393: functions without implementations
-----------------------------+----------------------------------------------
 Reporter:  c_maeder         |          Owner:  nobody  
     Type:  feature request  |         Status:  assigned
 Priority:  lowest           |      Milestone:  6.8     
Component:  None             |        Version:  None    
 Severity:  minor            |     Resolution:  None    
 Keywords:                   |     Difficulty:  Unknown 
 Testcase:                   |   Architecture:  Unknown 
       Os:  Unknown          |  
-----------------------------+----------------------------------------------
Changes (by igloo):

  * architecture:  => Unknown
  * difficulty:  => Unknown
  * milestone:  => 6.8
  * testcase:  =>
  * os:  => Unknown

Old description:

> {{{
> Allow to declare a function by only supplying its type
> signature.
> This feature shall enhance rapid prototyping by fixing
> an interface but leaving some functions unimplemented.
>
> Currently this can be (only) simulated by supplying
> dummy implementations, like
>
> f :: ...
> f = undefined
>
> Since it is possible to supply dummy data types by
> "data T" (not followed by "="), allowing functions
> without implementations seems almost to be a logical
> consequence. Surely, the compiler should emit warnings
> for missing implementations.
>
> It would be nice if such function declarations via type
> signatures could be repeated at any position within a
> module.
>
> }}}

New description:

 {{{
 Allow to declare a function by only supplying its type
 signature.
 This feature shall enhance rapid prototyping by fixing
 an interface but leaving some functions unimplemented.

 Currently this can be (only) simulated by supplying
 dummy implementations, like

 f :: ...
 f = undefined

 Since it is possible to supply dummy data types by
 "data T" (not followed by "="), allowing functions
 without implementations seems almost to be a logical
 consequence. Surely, the compiler should emit warnings
 for missing implementations.

 It would be nice if such function declarations via type
 signatures could be repeated at any position within a
 module.

 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/393>
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