id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
2660,Add Down newtype wrapper for reversing orderings,twanvl,,"In the same spirit as the newtypes in Data.Monoid, we can also add a newtype for reversing the ordering of a type:
{{{
newtype Down a = Down { getDown :: a }

instance Ord a => Ord (Down a) where
    Down x < Down y  =  y < x
    -- etc.
}}}
This newtype is especially useful in combination with `sortOn` (ticket #2629).",proposal,closed,normal,Not GHC,libraries/base,6.8.3,wontfix,,,Unknown/Multiple,Unknown/Multiple,None/Unknown,Unknown,,,,