proposal #2461: add Traversable generalizations?of?mapAccumL?and mapAccumR

[Nicolas Pouillard]

Excerpts from Michael Karcher's message of Mon Jul 28 10:48:34 +0200 2008:
> Conor McBride <conor at strictlypositive.org> wrote:
> > Michael wrote
> > > > David wrote (with patch applied):
> [...]
> > > >  (Backward f) <*> (Backward a) = Backward (a <**> f)
> > > According to the haddock of Control.Applicative, this line is  
> > > semantically
> > > equivalent to
> > >   Backward f <*> Backward a = Backward (f <*> a)
> > I'm not saying the haddock is entirely clear, but it certainly
> > doesn't necessitate the interpretation you're making.
> 
> OK, right. But the text "A variant of <*> with the arguments reversed"
> at least sounds like "<**> = flip <*>", which obviously is untrue
> then.

I've also understood "<**> = flip <*>" when reading the docs :(

-- 
Nicolas Pouillard aka Ertai
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