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

[Dan Piponi]

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