Proposal: Significant performance improvements for Data.Map

[Don Stewart]

igloo:
> On Fri, Sep 03, 2010 at 06:04:21PM +0200, Johan Tibell wrote:
> > On Fri, Sep 3, 2010 at 5:07 PM, Ian Lynagh <igloo at earth.li> wrote:
> > 
> > > > +{-# DEPRECATED fold "Use foldrWithKey instead" #-}
> > > > +{-# DEPRECATED foldWithKey "Use foldrWithKey instead" #-}
> > >
> > > I didn't expect to see DEPRECATED pragmas being added in the middle of a
> > > patch called "Performance improvements to Data.Map"!
> > >
> > > Why have these been deprecated?
> > 
> > They were already deprecated in the Haddock comments so I took the liberty
> > to add a deprecate pragma. If people disagree with this we could remove
> > them.
> 
> Aha, there's a comment:
> 
> -- This is identical to 'foldrWithKey', and you should use that one instead of
> -- this one.  This name is kept for backward compatibility.
> 
> It's 2 years old, so adding a DEPRECATED pragma sounds reasonable to me.
> 
> But I don't see a comment saying fold is deprecated. Do we know anything
> about how often folding is done on Maps with and without a key? e.g. any
> figures from hackage?
> 

I'd like to survey the use of all api functions. Some have ZERO use
across 25k hackage modules. Stay tuned.