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From: "David Botton" <David@Botton.com>
Subject: Re: Access to procedures
Date: 1999/06/25
Message-ID: <7kvuji$1vae$1@news.gate.net>#1/1
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References: <37737285.5CF9ED5F@Maths.UniNe.CH>
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Date: 1999-06-25T13:01:38+00:00
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You could also move your main's My_feedback procedure to library level and
that would solve the problem.

David Botton


Gautier wrote in message <37737285.5CF9ED5F@Maths.UniNe.CH>...
>Hello, Reference Manual gurus!
>
>I've encountered a stupid but sticky problem by implementing my
>Unzip-Ada project. In the interactive versions of extract procedures,
>I pass an access to a feedback procedure for display & interaction.
>
>*But* whatever the way I nest and subtype the things, the compiler
>(GNAT) tells me (certainly with good reasons):
>
>"subprogram must not be deeper than access type"
>
>even when it doesn't seem depper at all! So, my question is:
>how to do it ?
>
>The code in question is :
>
>* in Unzip package spec :
>
> type feedback_proc is access
>   procedure ( percents_done: in natural; user_abort: out boolean );
>
>  procedure Extract(from : zip_info; what : String;
>                    method     : out pkzip_method;
>                    feedback   : feedback_proc );
>
>* in a main program (one of many attempts!) :
>
>  subtype local_feedback_proc is feedback_proc;
>
>  procedure My_feedback( percents_done: natural; user_abort: out boolean
>) is
>    new_done_dots: natural:= (dots * percents_done) / 100;
>    begin
>      for i in done_dots .. new_done_dots loop
>        Put('.');
>      end loop;
>      user_abort:= false;
>    end My_feedback;
>
>  -- My_feedback_access: constant local_feedback_proc:= My_feedback'access;
>
>  procedure Do_Unzip is
>    begin
>...
>          Extract( zi, Argument(i), method, My_feedback_access );
>    end Do_unzip;
>
>NB: a generic solution doesn't seem a solution as some packages,
>basically non-generic, have to call the feedback procedure; making
>the whole generic could become heavy.
>
>--
>Gautier
>
>--------
>http://members.xoom.com/gdemont/