[GHC] #1134: swap minView/maxView return value

[GHC]

#1134: swap minView/maxView return value
-----------------------------+----------------------------------------------
 Reporter:  jpbernardy       |          Owner:  jpbernardy 
     Type:  feature request  |         Status:  new        
 Priority:  normal           |      Milestone:  6.8        
Component:  libraries/base   |        Version:  6.6        
 Severity:  normal           |     Resolution:             
 Keywords:  collections      |     Difficulty:  Easy (1 hr)
 Testcase:                   |   Architecture:  Unknown    
       Os:  Unknown          |  
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Old description:

> New proposed types:
>
> Data.Set:
>
> minView,maxView:: Monad m => Set a -> m (a, Set a)
>
> Data.Map:
>
> minViewWithKey,maxViewWithKey :: Monad m => Map k a -> m ((k,a), Map k a)
>
> minView,maxView :: Monad m => Map k a -> m (a, Map k a)

New description:

 Some time ago (before ghc 6.6 / base 2.0 release), I introduced minView
 and maxView in Data.Set and Data.Map (at a user's request). I agreed with
 Robert Dockins to implement the same functionality as in his version of
 the Edison library. Unfortunately, I uselessly swapped the return values
 of minView and maxView, introducing a difference both with the
 corresponding functions in the edison library and similar functions in
 Data.Map/Set.

 I propose to restore the symmetry, at the cost of incompatibility.


 New proposed types:

 Data.Set:

 minView,maxView:: Monad m => Set a -> m (a, Set a)

 Data.Map:

 minViewWithKey,maxViewWithKey :: Monad m => Map k a -> m ((k,a), Map k a)

 minView,maxView :: Monad m => Map k a -> m (a, Map k a)

 The incompatibility is probably acceptable because the functions are still
 short-lived.

 relevant urls:
 http://www.eecs.tufts.edu/~rdocki01/docs/edison/Data-Edison-
 Coll.html#v%3AminView
 http://www.eecs.tufts.edu/~rdocki01/docs/edison/Data-Edison-
 Assoc.html#v%3AminView
 http://hackage.haskell.org/darcsweb/darcsweb.cgi?r=base;a=commit;h
 =20060616180121-9c550-c9530b7eab87ea834f826a7d5c531a5bbed22306.gz

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1134>
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