Re: Magnavox consultant trashes Ada tools in IEEE Computer

[emery@goldfinger.mitre.org (David Emery)]

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
--
--The preceeding opinions do not necessarily reflect the opinions of
--The MITRE Corporation or its sponsors. 
-- "A good plan violently executed -NOW- is better than a perfect plan
--  next week"                                      George Patton
-- "Any damn fool can write a plan.  It's the execution that gets you
--  all screwed up"                              James Hollingsworth
-------------------------------------------------------------------------