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From: "Harrison, John R" <johnh@ichips.intel.com>
To: "Xavier Leroy" <Xavier.Leroy@inria.fr>
Cc: "caml-list" <caml-list@inria.fr>
Subject: RE: [Caml-list] Are you sure the new "=" of 3.08 is good ?
Date: Sat, 9 Oct 2004 11:10:30 -0700	[thread overview]
Message-ID: <012676D607FCF54E986746512C22CE7D0FE7BE@orsmsx407> (raw)

| As I said in an earlier post, you can do
| 
|   let (=?) x y = (Pervasives.compare x y = 0)
| 
| and use =? instead of = in places where you need the "early stop"
| behaviour.

OK. I wanted to be sure this was a recommended solution, not just
something that happens to work at the moment.

| Of course, if the speed of equality is critical, you can also define
| your own comparison functions for the types of interest, or even (as
| Damien suggested) implement hash-consing.

In fact, the key function is an alpha-conversion test on
name-carrying lambda-terms. Since it's almost always expected to
succeed with full equality after a shallow comparison, I now do an
equality test first to get the early-out behaviour. I can just
change it to put an "==" into the main recursion when it hasn't
gone through any lambdas.

John.

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             reply	other threads:[~2004-10-09 18:10 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-10-09 18:10 Harrison, John R [this message]
  -- strict thread matches above, loose matches on Subject: below --
2004-10-09 17:56 Harrison, John R
2004-10-08 16:35 Harrison, John R
2004-10-08 17:34 ` Damien Doligez
2004-10-09  8:58 ` Xavier Leroy
2004-10-08 16:25 Harrison, John R
2004-10-08  2:54 Harrison, John R
2004-10-08  5:49 ` Christophe Raffalli
2004-10-08  6:54   ` David Brown
2004-10-07 21:14 Christophe Raffalli
2004-10-08  7:38 ` Jean-Christophe Filliatre
2004-10-08  8:31   ` Christophe Raffalli
2004-10-08 15:10     ` Damien Doligez
2004-10-08  9:37 ` Sébastien Furic
2004-10-08 15:54 ` Xavier Leroy

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