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

[piercarl@sabi.demon.co.uk (Piercarlo Grandi)]

>>> "snowballinfo" == Snowball  <snowballinfo@rase.com> writes:

snowballinfo> Robert C. Martin wrote:

Robert> Objects execute inside computers.

I would say that they can be stored; given that most OO systems are not
actor based, the idea that objects "execute" lacks generality.

Robert> They take up memory space and CPU cycles.

Usually but not always...

Robert> Classes are source code.

Never; they are linguistic constructs, often represented as source code
(but not always: for example in Smalltalk-80 there is no source code
representation for classes, only printed, displayed and reified
representations).

There is an interesting section in Bjarne's Stroustrup's "The design and
evolution of C++" on decoupling languages from their textual
representation as source code as a possible evolution of C++, on page
207, with title "Beyond files and Syntax":

  "  A C++ program contains a wealth of information that in a typical
  environment is available only to a compiler. I want that information
  at the programmer's fingertips. However, most people look at a C++
  programs as a set of source files  or as a string of characters. That
  is to confuse the representation with what is represented. A program
  is a collection of types, functions, statements, etc. To fit
  traditional programming environments, these concepts are represented
  as characters in files.
     Basing C++ implementations on character oriented tools has been a
  major impediment  to progress. [ ... much more ... ]"

I personally sympathize with the sentiment, but after many years I have
become persuaded that there is no hope of easy interchange except in
text files, and that easy interchange is of such paramount importance
that it overrides even the desires to have the representation of a
program in a more directly structural form than a stream of characters.

Robert> They specify the objects and create a structure from which the
Robert> objects are created.

snowballinfo> This is true for C++ and some other languages, however for
snowballinfo> Smalltalk Classes are objects which take up memory space
snowballinfo> (and sometimes CPU cycles).

Well, surely not in Smalltalk-80, which is arguably the ``classic''
Smalltalk that most people have heard of; which is the Smalltalk dialect
you are thinking of in which classes are objects, instead of being
merely represented by objects as in Smalltalk-80? Can it still be called
``Smalltalk''? After all that classes are not objects and that the two
concepts are very distinct is one of the major design decisions of
Smalltalk-80 (in the early versions of PARC Smalltalk the distinction
was, arguably, not that sharp).