From: Wei Hu <weihu@cs.virginia.edu>
To: caml-list@inria.fr
Subject: Predicativity?
Date: Mon, 15 Sep 2008 07:26:14 +0000 (UTC) [thread overview]
Message-ID: <loom.20080915T071146-518@post.gmane.org> (raw)
Hello,
Isn't OCaml's polymorphism predicative? Then, why does the following code in
the interactive toplevel type check?
# let id x = x;;
val id : 'a -> 'a = <fun>
# let f x = (id id) x;;
val f : 'a -> 'a = <fun>
I thought id could not be applied to itself under predicative polymorphism. Is
my understanding wrong? Can you show an example that doesn't type check in
OCaml, but would type check under impredicate polymorphism?
Thanks!
reply other threads:[~2008-09-15 15:20 UTC|newest]
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