RE: Ada95 and UML

["Robert C. Leif, Ph.D." <rleif@rleif.com>]

From: Bob Leif
To: Robert Palasek et al.

The first question to ask is, what would be useful for the Ada community?
Ada specifications include a significant and very useful part of a model.
I believe that the Ada paradigm is correct--Leave the details to the body
and probably the private parts. Therefore I believe that the private part of
the specification should be omitted from a model. Since a graphical method
of describing the software appears to be useful, it makes sense to create or
preferably extend an already existing technology.

As some of you know, I suffer from an XML fixation. Actually, I view XML as
a very good means to improve Ada's use. XML has the common features with Ada
of enumerated types and ranges. Therefore the same graphical tool could be
employed to model and perhaps generate Ada specifications and/or XML
schemas. Or any one of the three could be used to generate part or all of
the other two.

This would permit one to storyboard a project. The screens including forms
could be created with commercial XML tools. The appropriate schemas would
then be created. DTDs should be translated into schemas, which are much
easier to understand.

-----Original Message-----
From: comp.lang.ada-admin@ada.eu.org
[mailto:comp.lang.ada-admin@ada.eu.org]On Behalf Of Robert Palasek
Sent: Tuesday, April 24, 2001 6:53 AM
To: comp.lang.ada@ada.eu.org
Subject: Re: ada95 and uml


bobpalasek wrote:

> > But I don't understand the idea that you are supposed to be able to
> > generate one from the other.  That seems wrong and misguided to me.
> >
> >  A model is an abstraction that carries some proper subset of
> > salient points of the thing being modeled.  For it to be useful, the
> > model has to leave other stuff out.  If it doesn't leave anything
> > out, it's just an alternate representation.
>

Simon writes:
> True; model + translation rules -> code. This is possible provided
> your model is expressed with the precision required by the translation
> rules[1].

What Simon writes is true of any formal rewriting system.
As stated, it maybe too general to be useful.

Let us suppose, however, that in this context "model" is limited to
UML, and "code" stands for Ada.

  In this hypothetical situation, it should be possible to
go from the model to an executable, and not very many people
at all need to be concerned with the intermediate representation.
Assembly language or machine code is fine. No need to bother
anyone with Ada.  Keep it simple.

  But my conceit misses the point of using modeling as
an abstraction to help understand the problem and/or the
solution.  The model is deliberately more simple than the final
design and implementation.  That is the nature of modeling.
To require the model to carry all the details seems misguided,
sophomoric, to me.