From: "Ryan Tarpine" <rtarpine@hotmail.com>
To: ctchou@mipos2.intel.com, caml-list@inria.fr
Subject: Re: [Caml-list] Weird typing problem
Date: Tue, 21 May 2002 20:14:21 -0400 [thread overview]
Message-ID: <F218jp3b6uIU1Gj03oH000021c7@hotmail.com> (raw)
>From: Ching-Tsun Chou <ctchou@mipos2.intel.com>
>To: caml-list@inria.fr
>Subject: Re: [Caml-list] Weird typing problem
>Date: Tue, 21 May 2002 16:58:32 -0700 (PDT)
>
>Why can't the compiler just substitute 'a for '_a if '_a can't be
>resolved? What's wrong with that? Surely O'Caml can handle
>polymorphism.
>
>- Ching Tsun
>-------------------
See http://caml.inria.fr/FAQ/FAQ_EXPERT-eng.html#polymorphisme. In short,
(quoted from the FAQ)
When type-checking
let name = expr1 ...
The type of expr1 is generalized when expr1 is a function, an dentifier or a
constant. Otherwise the identifier name is not polymorphic (type variables
are not generalized).
...
The new rule implies that if expr1 is a function application, then the
identifier name is monomorphic
This is done because "a secure type system for Caml must forbid the
existence of polymorphic mutable values at run-time" and this was basically
the easiest way to do it. Read the FAQ for an example.
HTH,
Ryan Tarpine, rtarpine@hotmail.com
"To err is human, to compute divine. Trust your computer but not its
programmer."
- Morris Kingston
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next reply other threads:[~2002-05-22 0:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-05-22 0:14 Ryan Tarpine [this message]
[not found] <F143h1mIs1Dk3fqSUVd000021b5@hotmail.com>
2002-05-21 23:58 ` Ching-Tsun Chou
-- strict thread matches above, loose matches on Subject: below --
2002-05-21 23:48 Ryan Tarpine
2002-05-21 22:13 Ching-Tsun Chou
2002-05-21 23:03 ` Pixel
2002-05-21 23:20 ` Ching-Tsun Chou
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