Re: Printing Enum Variable Re: Linux World

[robert_dewar@my-dejanews.com]

> There is a point of view in the OOP community that says
> that enumeration types arean artifact of an obsolete
> style of programming.  That is, an enumeration type,
> because it is not extensible and cannot be further
> specialized, is antithetical to OOP.  Although I find
> this viewpoint a little too narrow for my taste, one
> could make a very good case to support it in many
> situations.

It is odd. Every few years, some new group of people
rediscover Church's thesis. They develop a new paradigm
and make the amazing discovery that they can manage to
program any computing problem using this paradigm. They
then conclude that one *ought* to use the paradigm 100%
of the time, some examples are:

  goto-free programming
  top down structured programming
  applicative/functional programming
  data flow programming
  integration of correctness proofs
  logic programming
  ...

and of course, most recently

  object oriented programming

It's really a very puzzling phenomenon. If you step back
and take a broader view, it is amazingly obvious that these
narrow viewpoints are just that, narrow, and that the far
more reasonable viewpoint is that we have a variety of
paradigms, and should use the one, or the mixture that is
appropriate to the problem at hand.

Yes, of course it is problematic to use an enumeration type
if one expects to make frequent changes to the set of
values in a manner that does not really correspond to the
abstraction in the first place. For example, it is a
definite mistake to try to model errno across targets as an
enumeration type, since the set of codes will change
frequently, and it is simply unhelpful to use an
enumeration type in this situation.

On the other hand, complaining about

  type day is (Sun, Mon, Tue, Wed, Thu, Fri, Sat);

on the grounds it does not allow for easy extension is
good only for inclusion in a set of bad jokes.

Extensible types and dynamic dispatching are certainly
useful techniques *some of the time*. If you get into a
way of thinking that ALL variant types and case statements
must be replaced with this approach, you will create a mess
for some problems where the case statements are more
appropriate.

This really is such obvious stuff that it should not need
saying, but I still find that we are beset by fanatics who
are singing the latest "do it my way, it is the only true
way" song!

Robert Dewar

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