From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <Xavier.Leroy@inria.fr>
X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on yquem.inria.fr
X-Spam-Level: 
X-Spam-Status: No, score=0.0 required=5.0 tests=AWL autolearn=disabled 
	version=3.1.3
Received: from discorde.inria.fr (discorde.inria.fr [192.93.2.38])
	by yquem.inria.fr (Postfix) with ESMTP id CE504BC0A
	for <caml-list@yquem.inria.fr>; Thu, 26 Apr 2007 11:25:12 +0200 (CEST)
Received: from [128.93.11.95] (estephe.inria.fr [128.93.11.95])
	by discorde.inria.fr (8.13.6/8.13.6) with ESMTP id l3Q9P02R024472;
	Thu, 26 Apr 2007 11:25:00 +0200
Message-ID: <46306FEC.7010201@inria.fr>
Date: Thu, 26 Apr 2007 11:25:00 +0200
From: Xavier Leroy <Xavier.Leroy@inria.fr>
User-Agent: Thunderbird 1.5.0.7 (X11/20060915)
MIME-Version: 1.0
To: Tom <tom.primozic@gmail.com>
Cc: skaller <skaller@users.sourceforge.net>,
	Caml List <caml-list@yquem.inria.fr>
Subject: Re: [Caml-list] Function application implementation
References: <c1490a380704251538i7d8086e7u9bb50d9d5d82cfd4@mail.gmail.com>	<1177557207.8088.27.camel@rosella.wigram> <c1490a380704260152h34df93e9p20decd2f13459bbe@mail.gmail.com>
In-Reply-To: <c1490a380704260152h34df93e9p20decd2f13459bbe@mail.gmail.com>
X-Enigmail-Version: 0.94.0.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
X-Miltered: at discorde with ID 46306FEC.002 by Joe's j-chkmail (http://j-chkmail . ensmp . fr)!
X-Spam: no; 0.00; ocaml:01 stack:01 05.:98 abstract:01 caml-list:01 xleroy:01 closure:01 expression:02 evaluates:02 talks:03 talks:03 generated:05 xavier:06 xavier:06 inria:06 

>     It knows the type of the function expression, and that is all
>     that is required. Incidentally Ocaml evaluates right to left. So
>
>             f x y z
>
>     will be roughly:
>
>             push (eval z)
>             push (eval y)
>             push (eval x)
>             push (eval f)
>             apply
>             apply
>             apply
>
>
> But that doesn't explain how does each apply know what to do, either to
> build a new closure (in the case above, the first two applies) or to
> actually call the code (the third apply).

The generated abstract machine code is more like:
             push (eval z)
             push (eval y)
             push (eval x)
             push (eval f)
             apply 3        (*  number of arguments provided *)

"apply" doesn't do anything clever, it just enters the code of the
called function f.  It's the code of f that determines what to do
with the arguments provided on the stack.

More details can be found in one of my talks:
http://gallium.inria.fr/~xleroy/talks/zam-kazam05.pdf

- Xavier Leroy