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Date: Tue, 2 Sep 2003 12:26:13 +0200
From: Michal Moskal <malekith@pld-linux.org>
To: Lukasz Stafiniak <luk_stafi@wp.pl>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] Let-in vs beta-redex
Message-ID: <20030902102613.GA19386@ep09.kernel.pl>
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On Mon, Sep 01, 2003 at 06:15:54PM +0200, Lukasz Stafiniak wrote:
> Hi,
> 
> Is let-in more efficient than beta-redex or are they computationally
> equivalent? Is let-in a syntax-sugar of beta-redex?
> 
> E.g.
> 
> let x = sin 2. in x *. x *. x;;
> 
> (fun x -> x *. x *. x) (sin 2.);;

let in is *not* equivalent to beta-redex because of typing. Type
variables are not generalized in beta-redex, for example consider:

let id x = x in
(id 1, id true)

vs.

(fun id -> (id 1, id true)) (fun x -> x)

-- 
: Michal Moskal :: http://www.kernel.pl/~malekith : GCS {C,UL}++++$ a? !tv
: PLD Linux ::::::::: Wroclaw University, CS Dept : {E-,w}-- {b++,e}>+++ h

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