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From: emery@goldfinger.mitre.org (David Emery)
Newsgroups: comp.lang.ada
Subject: Re: Magnavox consultant trashes Ada tools in IEEE Computer
Date: 1 Nov 94 10:18:24
Organization: The Mitre Corp., Bedford, MA.
Message-ID: <EMERY.94Nov1101824@goldfinger.mitre.org>
References: <9410272051.AA16079@ajpo.sei.cmu.edu>
 <CyE29E.1K9@inmet.camb.inmet.com>
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In-reply-to: mg@asp.camb.inmet.com's message of Fri, 28 Oct 1994 15:12:49 GMT
Date: 1994-11-01T10:18:24+00:00
List-Id: <comp.lang.ada>

Mitch wrote: 
>Something ...caused Magnavox to go the direction of using lots of
>very deeply nested subunits, and lots of parent and child libraries.
>Rational subsystems were mapped into Alsys parent-child libraries.
>They were using a library structure with parent-child-grandchild... to
>at least 10 levels deep. 

It's worth noting that I've seen similar problems with other compiler
systems.  A contractor that shall remain nameless once used a very
strict functional decomposition methodology with Ada.  Their mapping
to Ada was to use subunits.  So you ended up with:

	procedure Main is
          procedure Level1_Op1 is separate;
          procedure Level1_Op2 is separate;
        begin
          Level1_Op1;
          Level1_Op2;
	end Main;

	separate
	(Main)
	procedure Level1_Op1 is
	  procedure Level2_Op1 is separate;
          procedure Level2_Op2 is separate;
        begin
	  Level2_Op1;
	  Level2_Op2;
	end;

	separate
	(Main.Level1_Op1)
	procedure Level2_Op1 is ...

The compiler performance, by the time you got down to 
"separate (Main.Level1_Op1.Level2_Op1.Level3_Op1.Level4_Op1) 
 procedure Level5_Op1 is"

The compiler can have a heluva time creating the appropriate context
for a deeply nested subunit.

				dave
--
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