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From: bertrand@eiffel.UUCP (Bertrand Meyer)
Newsgroups: comp.lang.c++
Subject: Re: Problems maintaining header files
Message-ID: <490@eiffel.UUCP>
Date: 31 Jan 91 23:55:46 GMT
References: <15917@reed.UUCP> <6107@stpstn.UUCP> <486@eiffel.UUCP> <7091@exodus.Eng.Sun.COM>
Organization: Interactive Software Engineering, Santa Barbara CA
Lines: 73

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From <7091@exodus.Eng.Sun.COM> by chased@rbbb.Eng.Sun.COM (David Chase):

> I think you [i.e. Hadil G. Sabbagh] have missed [B. Meyer's] point;
> these features [no need for make files, header files etc.]
> need not be unique to Eiffel.

	Mr. Chase is quite correct. He mentions Mesa and Modula-3, and I
have no doubt that automatic dependency analysis can be implemented
in these languages. Another language for which I have seen
programming environments which perform similar work is Ada.

	A full-fledged object-oriented language does make
the problem more challenging technically (because of multiple
and repeated inheritance, cycles in the client relation etc.).
The point of my message was that for automatic dependency analysis
to work the language design has to make it possible. This is true
for Ada, Eiffel, Mesa and (from the looks of it) Modula-3.
There are undoubtedly other examples.

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	My message discussed a specific point (header files), mentioning
Eiffel in response to a message mentioning Objective-C. Mr. Sabbagh
used this opportunity to include general comments about Eiffel
which are more political than technical, and not connected to
the matter of header files. Let it be registered that I do
not intend to help start a general political Eiffel-C++ debate.
However I do need to correct the inaccuracies regarding Eiffel
in Mr. Sabbagh's four points:

>> 1. Eiffel isn't available on micros; C++ is.
>> 2. Eiffel is supported by only one vendor (2 since Abajton licensed it
   to port to Mac; who knows when this will happen?).

Eiffel is available on micros under Unix, although it is true
that no MS-DOS implementation is available yet. However
an independent DOS implementation, by a German company,
has been announced and will be demonstrated at CeBIT in March.
I saw an early version in October and was quite impressed.
We know of several other ongoing independent efforts.

> 3. Eiffel is a GREAT IDEA IN THEORY; major obstacles exist to
> implementing a lot of its great features.

	What does this mean? All of Eiffel features have been implemented
and are being used since 1986 by thousands of people worldwide.
Please don't propagate the ``it's like Algol 60'' myth.

> 4. There is far more experience with C++ on real projects than with
> Eiffel.

There are certainly more people using C++ today, although
there is more Eiffel usage than one would think by reading
only the current technical press.

In the absence of scientifically collected evidence, however,
there are good reasons to believe that the body of actual
object-oriented development experience (significant projects
using O-O methodology, as opposed to small experiments, or
just C programming labelled C++) is at least as strong on the
Eiffel side.

To close, the following bears repeating: my only intent
in the second part of this message is to correct inaccuracies,
not to waste any more of anyone's time on non-technical language
comparisons.
-- 
-- Bertrand Meyer
bertrand@eiffel.com