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Team Ada: Ada Programming Language Advocacy


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Wed, 12 Jul 2000 09:41:15 +0000
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>Sorry to go off topic, but one of the things that I like about Ada is that
>it is a Standard with minimal compromise.

This is very true. It is clear that a lot of effort has been made with the Ada
standard to make it encompass pretty much all the could be needed at the moment.

While I agree in principle with your feelings on adherence to standards, if all
compiler products adhered strictly to the standards for their respective
languages, it is unlikely that we would ever build any software that did
anything useful. Although Ada is very good in this respect, there are still a
great number of implementation defined features that can (and do) reduce the
portability of an application across different compilers.

As far as standards go, ISO Pascal is (was?) a prime case of a language being
defined for a specific purpose, and then being hijacked for use in industry. If
the Pascal compilers in those days had adhered to the standard, there is a good
chance that it would never have been used in industry, as it was pretty much
useless as a production lanaguage! In my early days at Marconi Space Systems, I
used Tektronix Pascal for 6 months or so for an 8086 target, then moved onto
using VAX Pascal for a couple of years. It was like using a totally different
language, sure the basic syntax was the same (well, similar), but the things you
could do with it were amazing compared with the Tektronix implementation. To be
honest, if it hadn't been for the implementation specific extensions that a
large number of companies (e.g. DEC, Tektronix, Borland etc) had made to Pascal,
it would not have gained such wide acceptance, and would more than likely *not*
have had such a significant effect on the design of what is now Ada.

My personal view is that an implementation should always provide the features
required by the relevant standard. Whether it provides, or should be allowed to
provide, an implementation defined superset depends on the application domain.

It may seem reasonable for example for Microsoft to add implementation specific
extensions to produce Visual C++, however for something which is less
platform-specific (such as HTML), this seems to me to be unreasonable (as
appears to have been shown with the ASE Community problems).

Ultimately, if the standard facilities are provided by an implementation, is it
reasonable to assume that those facilities are all that are required for an
application to work?