Re: c++ "with" keyword

[dewar@gnat.com (Robert Dewar)]

> See Algol 68 for what happens if you do it the other way...

I am willing to bet that this comment is made with *ZERO* knowledge
about Algol-68. In fact the Algol-68 standard was remarkably complete
and successful, and in environments where full Algol-69 compilers
became available (notably on the ICL-9000 and CDC-6000 series machines
it was widely used). The issue of why it was not more successful is
a commercial/marketing one, which had very little if anything to do
with the way the standard was produced.

I am certainly not opposed to experimentation with new features
using existing compilers (GNAT has been used this way in the Adaq
community, for example we implemented "with type" pretty early on
and partly as a result of this experience, we have learned that it
was not the best approach). But discussion and suggestions of new
features are best carried out in forums primarily populated by
users and language designers, rather than compiler implementors.

Another danger of course is that if a half baked feature is
implemented, then it gets stuck and never removed (we will in
fact remove the "WITH TYPE" feature in GNAT when a better
substitute comes along, even though it will discombobulate
people). It is too easy to argue for keeping junk stuff around
for compatibility reasons (witness recent thread here in which
some argued that junk illegal semicolons should be accepted in
C++ due to the existence of incorrect code :-)