Re: OO puzzle

[swhalen@netcom.com]

Ehud Lamm <mslamm@mscc.huji.ac.il> wrote:
...
: Your classification is correct, but in itself doesn't provide the
: prescriptive answer of how to design a language in such a way as to
: ensure as much can be done during compile time, as possible without
: hurting expressablity to much. This question is naturally not a
: question that can be answered shortly and with a definitive answer.
: Hence we see some differences even among mostly similar languages.
...

I'm missing something here (which is not that unusual <g>).

I know Ada _much_ better than I know Eiffel, but my impression is
that Ada already _is_ designed

    "in such a way as to ensure as much can be done during compile
     time, as possible without hurting expressablity to much."

In many ways, that seems to me a good definition of one of the major
design goals (and successes) of Ada.

My impression of Eiffel is that from the start, it was intended that
having powerful OO constructs was a more important language design
constraint than early vs. late binding. I seem to remember that
Eiffel intended to have a larger and smarter run-time with many
class and conversion and compatibility issues deferred to run time
and not even be attempted at link time (to enhance OO "power" or
"clarity").

Aren't the differences you're highlighting inherent in the differing
design intents of the two languages? It seems to me that the
examples you give are right on the boundary of where Eiffel
intentionally went farther than Ada in order to enhance "OO clarity"
(and sacrificed link time error detection / efficiency).

Steve

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                Steve Whalen     swhalen@netcom.com
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