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From: dmitry@elros.cbb-automation.de (Dmitry A. Kazakov)
Newsgroups: comp.lang.ada
Subject: Re: Side-Effects in Functions [Rosen Trick]
Date: Mon, 05 Nov 2001 14:59:15 GMT
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Date: 2001-11-05T14:59:15+00:00
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On 5 Nov 2001 03:19:39 -0800, pete@nospam <pete_member@newsguy.com>
wrote:

>In article <3be666fe.6426140@News.CIS.DFN.DE>, dmitry@elros.cbb-automation.de
>says...
>>
> 
>>But what I presonally cannot understand is why not to allow
>>PROCEDUREs having a result, i.e.
>>
>>procedure Find (Folder : in out Table) return Table_Token;
>>
>>procedure GetNext  (Item_List : in out Iterator) return Element;
>>
> 
>this is a joke, right?

Nope. It is exactly what is required, namely a subroutine having a
distinguished parameter called result and allowed to modify its
arguments. It is not a function (in Ada sense), thus it is a
procedure. Compare:

procedure Find (Folder : in out Table) return Table_Token;

with

procedure Find (Folder : in out Table; Result : out Table_Token);

The difference between them is rather syntactical. Semantically they
do same: search table, cash internally the result of search (thus in
out for the fist argument), return the found element.

Regards,
Dmitry Kazakov