From: Tom <tom.primozic@gmail.com>
To: "Chris King" <colanderman@gmail.com>
Cc: "Jacques Carette" <carette@mcmaster.ca>, caml-list@yquem.inria.fr
Subject: Re: [Caml-list] Equality of functional values
Date: Tue, 30 Jan 2007 21:18:36 +0100 [thread overview]
Message-ID: <c1490a380701301218y1a92ec8ei5b4efbc714664b03@mail.gmail.com> (raw)
In-Reply-To: <875c7e070701300923r362b1032sac4125fd2879f8ae@mail.gmail.com>
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I guess the "correct" way to do = equality would be to check for tag (
Obj.tag (Obj.repr x)), and if it isn't float (or float array) then ==
equality would be performed first. The problem is that this would have to be
implemented by the OCaml developers, as the naive implementation:
let equal x y =
if Obj.tag (Obj.repr x) = Obj.double_tag then x = y
else
if x == y then true else x = y
doesn't work, as it should be called recursively (comparing two lists of
functions will fail, because the functions would be compared by =, not by
equal).
Actually, the implementation could be improved further, as it could actually
return true on examples such as
# let f x y = x + y;;
val f : int -> int -> int = <fun>
# f == f;;
- : bool = true
# (f 1) = (f 1);;
- : bool = true
because the parameters, passed to a closure, could be compared, too...
Anyhow, this can be added to the wishlist :)
- Tom
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next prev parent reply other threads:[~2007-01-30 20:18 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-29 21:04 Simon Frost
2007-01-29 21:11 ` [Caml-list] " Tom
2007-01-29 21:23 ` Brian Hurt
2007-01-29 21:59 ` Gerd Stolpmann
2007-01-30 8:17 ` Christophe Raffalli
2007-01-30 8:45 ` David MENTRE
2007-01-30 13:24 ` Andrej Bauer
2007-01-30 13:55 ` skaller
2007-01-30 14:21 ` Brian Hurt
2007-01-30 15:21 ` Jeff Polakow
2007-01-30 15:49 ` Jacques Carette
2007-01-30 17:23 ` Chris King
2007-01-30 20:18 ` Tom [this message]
2007-01-30 20:30 ` Gerd Stolpmann
2007-01-30 20:41 ` Fernando Alegre
2007-01-30 21:01 ` Christophe TROESTLER
2007-01-30 21:08 ` Tom
2007-01-30 21:46 ` Christophe TROESTLER
2007-01-30 22:05 ` Fernando Alegre
2007-01-30 23:13 ` skaller
2007-01-30 23:06 ` Andrej Bauer
2007-01-31 0:15 ` Jacques Carette
2007-01-31 7:03 ` Stefan Monnier
2007-01-31 12:54 ` [Caml-list] " Jacques Carette
2007-01-31 0:15 ` [Caml-list] " skaller
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