Re: organizing deep source trees with child packages

[Simon Wright <simon@pushface.org>]

Ludovic Brenta <ludovic@ludovic-brenta.org> writes:

> Simon Wright wrote on comp.lang.ada:
>> Ludovic Brenta <ludo...@ludovic-brenta.org> writes:
>>> There was a VCS integrated; I used it as part of Rational Apex on
>>> Solaris a few years ago.  I think it was slightly different from the
>>> original, as it used RCS as a storage back-end for source files and
>>> introduced the "subsystem" (consisting of many source files) as the
>>> preferred unit of configuration management.  Branching was OK but
>>> merging was horrible, as with RCS.
>>
>> The GNAT 'stand-alone library' is, I think, similar to the subsystem
>> in that only some of the units are externally visible. Of course you
>> _may_ be able to get a similar effect by using private child
>> packages.
>
> No, the "subsystem" in Rational has nothing to do with visibility; it
> was only a configuration management entity.  You could declare that a
> subsystem A with version number N depended on a subsystem B with
> version number M.  There was no mechanism (that I remember) to hide
> part of a subsystem from the outside.  And TTBOMK the GNAT 'stand-
> alone library' is not about version control or configuration
> management, since it is not versioned.

The paper at <http://dodreports.com/pdf/ada323647.pdf> - which is a
PDF'd scan - doesn't seem to agree with this;

on page 20, "The main reason for decomposing a system into subsystems is
to control and manage complexity."

on page 22, "a view [of a subsystem] manages: [...]  c. The visibility
to program units in other subsystems."

And the VCS - on the R1000 - was CMVC. I think that later versions of
APEX use ClearCase?