[Haskell-cafe] Re: Implementing "unionAll"

[Daniel Fischer]

Am Mittwoch 17 Februar 2010 17:46:38 schrieb Ozgur Akgun:
> > The easiest solution is simply to define
> >
> >    unionAll = nub . mergeAll
> >        where
> >        -- specialized definition of  nub
> >        nub = map head . groupBy (==)
>
> Talking about the easiest solution, I guess this is a quite easy way of
> defining unionAll as well: http://gist.github.com/306782
> I, of course, do not claim that it is more efficient or better. But I
> don't think it'd be rubbish :)

let
                next = minimum (map head xs') 

doesn't work if you have infinitely many lists :(