[Haskell-cafe] Convert Either to Tree - Occurs check

André Batista Martins andre_bm at netcabo.pt
Fri Oct 22 04:23:10 EDT 2010


Tks for the answer,
the data structure of Either is:


data  Either a b  =  Left a | Right b   deriving (Eq, Ord, Read, Show)

one example of what i want convert is:
 Left(Right(Left(Left())))


No dia 22 de Outubro de 2010 04:58, Dan Piponi <dpiponi at gmail.com> escreveu:

> André Batista Martins asked:
>
> >  i want convert  "Either" to a tree.
> >  Example:
> >                   Either ( Either  1 2 ) ( Either 3 4)     ---- >
> > Branch ( Branch (Leafl 1)  (Leafr2) ) ( Branch (Leafl 3)  (Leafr4)) )
>
> Before writing the function to convert your data structure, why not
> try writing down the precise type signature you expect it to have.
>
> In fact, before that, try writing down the precise type signature of
> the thing you call an "Either".
> --
> Dan
>
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