From: luc.maranget@inria.fr (Luc Maranget)
To: Christophe Raffalli <christophe.raffalli@univ-savoie.fr>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] Re: Help me find this pdf
Date: Fri, 19 Oct 2007 14:47:06 +0200 [thread overview]
Message-ID: <20071019124706.GA30305@yquem.inria.fr> (raw)
In-Reply-To: <4718A220.4030708@univ-savoie.fr>
>
> You mean that if I write (I use OCaml syntax)
>
> match p, q with
> | (true, true) -> A
> | _ -> B
>
> Haskell will first check if (p is evaluated and false) or (q is evaluated and false)
> and then, if it is not the case will evaluate p, and finally if p is true it will evaluate q ?
>
Haskell has left-to-right semantics for PM. Basically this is expressed
by PM compilation.
"Semantics" of the above code is given by:
match p with
| true -> (match q with true -> A | _ -> goto next enclosing "_")
| _ -> B
Hence if _|_ is a symbol for looping computation, and ?
is a symbol for just anything (in {_|_, true, false}),
we have:
p q -> result
_|_ ? -> _|_
true _|_ -> _|_
true true -> A
true false -> B
false ? -> B
>
>
> --
> Christophe Raffalli
In case you are really interested by the issue, may I mention
one of my recent papers on warnings for pattern matching
<http://pauillac.inria.fr/~maranget/papers/warn/index.html>
(See section 4.)
--Luc
next prev parent reply other threads:[~2007-10-19 12:47 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-18 9:52 Tom
2007-10-18 10:33 ` [Caml-list] " skaller
2007-10-18 11:01 ` Andreas Rossberg
2007-10-18 12:25 ` Jon Harrop
2007-10-18 12:40 ` Arnaud Spiwack
2007-10-18 13:17 ` Jon Harrop
2007-10-18 15:15 ` Till Varoquaux
2007-10-18 12:46 ` Jacques Garrigue
2007-10-18 13:57 ` Jon Harrop
2007-10-18 14:22 ` Brian Hurt
2007-10-18 14:52 ` Robert Fischer
2007-10-18 15:04 ` Eric Cooper
2007-10-18 17:18 ` Jon Harrop
2007-10-19 1:16 ` skaller
2007-10-19 5:09 ` Bárður Árantsson
2007-10-19 5:23 ` [Caml-list] " Erik de Castro Lopo
2007-10-19 5:46 ` Bárður Árantsson
2007-10-19 12:25 ` [Caml-list] " Christophe Raffalli
2007-10-19 12:47 ` Luc Maranget [this message]
2007-10-20 14:26 ` Christophe Raffalli
2007-10-19 14:48 ` Robert Fischer
2007-10-19 21:43 ` Andreas Rossberg
2007-10-19 21:51 ` Robert Fischer
2007-10-20 13:10 ` Andreas Rossberg
2007-10-19 23:10 ` Jon Harrop
2007-10-20 1:13 ` skaller
2007-10-20 6:36 ` Tom
2007-10-21 11:17 ` skaller
2007-10-19 8:55 ` Zheng Li
2007-10-19 22:27 ` [Caml-list] " Jon Harrop
2007-10-19 13:00 ` [Caml-list] " Brian Hurt
2007-10-19 13:49 ` Loup Vaillant
2007-10-19 14:41 ` Zheng Li
2007-10-19 23:09 ` [Caml-list] " Jon Harrop
2007-10-18 20:07 ` Tom
2007-10-19 0:59 ` skaller
2007-10-18 20:48 ` Lauri Alanko
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