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[Caml-list] References to polymorphic variants
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Date: | 2004-02-25 (16:33) |
From: | nickgrey@s... |
Subject: | [Caml-list] References to polymorphic variants |
Hi, I want to be able to store an arbitrary polymorphic variant in a reference: let (x : ([> ] option) ref ) = ref None ;; (Not my actual code, I've boiled it down to a minimal example.) This won't compile because it "contains a type variable which cannot be generalized". I understand this error message in other contexts. If my code were let x = ref None then I could break type safety by putting (Some 1) into the reference, and later reading the reference with type (string option) thus casting a string to an int. But as I'm dealing with a polymorphic variant, surely this should not apply. My understanding of polymorphic variants is that you do not need to specify at the time of declaration what types it might contain. So, what am I doing wrong and how can I get around it? Regards, Nick ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners