Version française
Home     About     Download     Resources     Contact us    
Browse thread
[Caml-list] Stupid question
[ Home ] [ Index: by date | by threads ]
[ Search: ]

[ Message by date: previous | next ] [ Message in thread: previous | next ] [ Thread: previous | next ]
Date: -- (:)
From: skaller <skaller@t...>
Subject: Re: [Caml-list] Stupid question
On Thu, 2004-01-15 at 11:03, Brian Hurt wrote:
> I was poking around in the produced assembly code of some ocaml code of 
> mine, and I noticed something.  The construct:
> 	if (x < m) <> (y < m) then
> 		...
> 
> when the compiler knows that x, y, and m are all ints, it calls an 
> external C routine to compare the two booleans.  But the construct:
> 
> 	if (x < m) != (y < m) then
> 		...
> 
> does not.  Now, this isn't a big deal- I just replaced <> with != and no 
> problem.  But I was kind of interested in why the compiler didn't catch 
> and optimize this.  Is there some sort of subtle semantic difference I'm 
> too dense to see?

Well, <> is a polymorphic value comparison.
Whereas != is a physical inequality comparison.

-- 
John Max Skaller, mailto:skaller@tpg.com.au
snail:25/85c Wigram Rd, Glebe, NSW 2037, Australia.
voice:61-2-9660-0850. Checkout Felix: http://felix.sf.net




-------------------
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