A trick (dirty ?) which would not slow down much performance of the
polymorphic equal would be to detect cyclic structure using the bit used
by the GC (the equallity will not trigger GC ?), and when you detect a
cycle, you either raise an exception or use physical equality depending
on the value of a global variable.



--
Christophe Raffalli
Université de Savoie
Batiment Le Chablais, bureau 21
73376 Le Bourget-du-Lac Cedex

tél: (33) 4 79 75 81 03
fax: (33) 4 79 75 87 42
mail: Christophe.Raffalli@univ-savoie.fr
www: http://www.lama.univ-savoie.fr/~RAFFALLI
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