Re: Ada and UML

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Wed, 01 Sep 2010 10:20:30 +0200, Matteo Bordin  
<matteo.bordin@gmail.com> a écrit:
> One of the goals of UML is to permits UML models to be implemented on
> several run-time platforms: for this to be possible, either you create
> a language which is the union of all possible computational models,
Unreachable target

> or you leave semantic variation points to permit model transformation
> (code generators) to inject platform-specific semantics following a
> precise pattern.
Look like the question I asked in a prior post : how is the source  
generator driven ?

> UML chose the second option. The core idea is that,
> by modeling your execution platform, you can "instruct" your code
> generator to generate code with a fully specified semantics for a
> precise target platform starting from an abstract model. This permits
> to re-use the same model for different target platforms by just
> changing code generator and platform model and to perform high-level
> verifications without including "pollution" from the underlying run-
> time.
I have the same view or except in one point : I do expect abstraction, but  
I do not expect automatic generation. Instead of the latter, I expect  
abstract view and outlining, which in turn lead to some other questions to  
solve, different than the one of automatic generation (will not talk about  
it here).

> The problem is that Ada Packages can have non-primitive operations and
> variables, but UML Packages can't.
So indeed, this really to not match Ada package.

As it seems some of my words was not understand (I may indeed be  
ambiguous) : when I say this is not the same as Ada package, I do not say  
I expect UML to be another way to write Ada, ... no, I wanted to  
understand things using concept which are already known.

> In UML a NameSpace is an abstract metaclass (a sort of abstract
> grammar rule), which is extended by concrete metaclasses. BTW, UML
> Class inherits from NameSpace: in UML a Class is a NameSpace.
I am not sure I understand this. Will later look for a way to understand  
it.

> They are part of the UML standard and can be found in true UML
> implementations such as those on the Eclipse platform (http://
> www.eclipse.org/modeling/mdt/?project=uml2tools, topcased.org,
> papyrusuml.org).
I have tried this. The first two did not want to lauch, only Papyrus  
could. I will try with it (I already tried it in the past, but this is  
another story I will not talk about).

>> I was a bit long with this reply, let go for a summary: give UML the
>> semantic of the target language (implies this choice is maid à-priori),
>> use notation restrictions as much as needed (should be documented, which
>> is OK, as UML seems to have provision for so called Preface).
>
> I disagree ;-) This approach means using UML at the same abstraction
> level of a traditioanl programming language.
Right, this have to be more abstract. But some stuff requires an exact  
semantic to be interpreted, and this is kind of concrete thing which you  
will typical find with a concrete language like Ada is.

> A desirable modeling
> approach based on languages of the UML family is to separate what is
> platform-independent from what is platform-specific to permit the re-
> use of platform-independent models. Let's make an example about
> tasking. You can have a platform-independent UML model where you
> identify "unit of concurrency". And another, platform-specific UML
> model where you describe the low-level implementation in terms of
> (Ada, C, ARINC-653, ...) tasks.
And how do you link these various more detailed model to the one which  
seems to be a master abstract model ?

> You may get more information on this approach by reading
> tutorials on MARTE (omgmarte.org).
I had a overiew. It is said to target Real-Time, which is not my direct  
concern, while seems it can be useful for general purpose. Thanks for this  
link.


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