self.python vs Current.eiffel

Warren Postma embed at NOSPAM.geocities.com
Tue Sep 26 15:38:58 CEST 2000


"Egbert Bouwman" <egbert at bork.demon.nl> wrote in message
news:mailman.969972580.17695.python-list at python.org...
> In a python method the following instruction is allowed:
>    self.x = self.x + a
> On page 187 of OOSC, Meyer seems to say that in Eiffel you cannot say:
>    Current.x := Current.x + a

I think that this stems from the "procedural" versus "mathematical" ways of
looking at a mathematical expression.

Forget all the programming langauges you know, go back to your school days,
and imagine the teacher writing on the black board a system of equations for
you to solve:

            y = x * 2
            x = x + 1

As an algebraic assertion (that X is itself equal to itself, plus 1) is an
impossibility.

I suspect that Meyer is coming from this very mathematical point of view,
and that treating a variable as an alias for a memory location is not an
abstraction he values as much as the mathematical "proveability" of
something.

Am I right? Am I wrong?

Warren Postma






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