[GHC] #9337: Add `sortOn` function to Data.List

[GHC]

#9337: Add `sortOn` function to Data.List
-------------------------------------------+-------------------------------
       Reporter:  JohnWiegley              |             Owner:
           Type:  feature request          |            Status:  new
       Priority:  normal                   |         Milestone:  7.10.1
      Component:  libraries/base           |           Version:  7.8.3
     Resolution:                           |          Keywords:
   Differential:                           |  Operating System:
   Architecture:  Unknown/Multiple         |  Unknown/Multiple
     Difficulty:  Easy (less than 1 hour)  |   Type of failure:
     Blocked By:                           |  None/Unknown
Related Tickets:                           |         Test Case:
                                           |          Blocking:
-------------------------------------------+-------------------------------

Comment (by JohnWiegley):

 hvr, you're right, this is a duplicate.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9337#comment:5>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler