Re: Interesting but sensitive topic to discuss (HELP: - OOP and CASE t

[nickt@bain.oz.au (Nick Thurn)]

Alan Lovejoy (alovejoy@concentric.net) wrote:
> Nick Thurn wrote:
> > 
> > alovejoy@concentric.net wrote 06.11.96:
> > >
> > > Class inheritance is an abstraction mechanism for code sharing.
> > > It has
> > > nothing much to do with architecture or design of a program.
> > >
[...]
> > So what pray tell *is* to do with architecture and design?
> 
> Architecture is a question of the division of responsibility among the
> objects and subsystems within a system.  It is about the roles that objects
> play, the relationships among and interactions between objects, and of how 
> objects collaborate to carry out their responsibilities.  Design is the
> process of converting a set of requirements into a specification of the
> types of objects than can exist and how objects of the specified types
> will operate as a system to satisfy the requirements.
> 
I totally agree! 

But objects are described by a text (smalltalk or otherwise) 
as classes that may be related by inheritance, containment or usage. 
Inheritance is not just code organisation (although it does organise code). 

I think there is a chicken and egg problem here. Architecture is expressed
in code and code is organised by architecture. My issue (and where I think
we agree) is that architecture is *more* important than code organisation
because:
	it is more fundamental to correctness of model
	code will be organised anyway by a "good" model
[...]
> 
> You are thinking in terms of some statically-typed
> language that uses classes as type contraints (such as C++).
>
> In a dynamically-typed language such as Smalltalk, it is syntactically legal 
> to send any message to any object.  If the object does not understand the message, 
> an error will be reported at run time.
> 
You are correct, I am thinking in statically typed terms. This does not invalidate
what I said. Sending "any message to any object" still requires the semantics
to be understood. The "typelessness" may be useful or may increase complexity. 
This is a design call and your milage may vary :) 

Nick (my opinions only)

> --
> Alan L. Lovejoy		|==============================================| 
> Smalltalk Consultant	|	Beware of Geeks bearing GIFs!	       |
> alovejoy@concentric.net |==============================================|