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From: hubert.fauque@wanadoo.fr
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To: caml-list@inria.fr
Subject: Re: Typing-problem
References: <Pine.GSO.3.96.990530171304.16161A-100000@kosh>
In-Reply-To: aXl's message of "Sun, 30 May 1999 17:24:50 +0200 (MET DST)"
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Date: 31 May 1999 14:42:20 +0200
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aXl <krauth@fmi.uni-passau.de> writes:

> Hi, 
> why is in the following example b of type "string -> string" ?

because a is of type string->string and b=a

> 
> 	let a = id id;;
> 	let b = a;;
> 	a "foo";; 
> 	(* until here it's covered by the faq's *)
> 	b;;

let b = a   defines a new name (b) for the object designed by a;
it doesn't construct a new object, and it doesn't do a new call (id id);

it is different from
let a = id id;;
let b = id id;;


The Caml let ..= ..  is different from the assignment in C or Pascal;
in C if you write
        a=b;
there is a variable "a" which already as a place
in memory, and a=b means: copy the memory location of b to a;

in Caml let defines a new name; it's the right of the = which may
construct a new object; that's why 
let a = id id
let b = a

is different from 
lat a = id id
let b = id id


Hubert
hubert.fauque@inria.fr