Re: Ada and Java. different behaviour. casting long to int problem.

[mgk25@cl.cam.ac.uk (Markus Kuhn)]

D'Arcy Smith <nospam@itools.symantec.com> writes:
|> I'm sure Ada has some silly things as well... I don't know what
|> they are since I've never used it.

Actually, they are in my opinion pretty rare now. Ada83 was a clean
design from scratch, which was very neat but also had quite a few important
bits missing (most notable object inheritance) and had a few rather
strange limitations. These however were thoroughly fixed when Ada was
completely revised in 1995 from ground up, building on over a decade of
experience with the first Ada language. The new second Ada language is a
real beauty now IMHO and we finally have also free and low-cost
high-quality development environments such as the GNU Ada95 compiler
available for it. Definitely worth having a look at, especially if
Java got you interested in new modern languages, but did not fully
live up to your expectations.

I consider Ada95 and Java to be the by far most interesting
production programming languages around in 1999 (as opposed to
experimental academic languages). They do target different application
areas however. While Java was designed for maximum portability and
GUI-oriented application software that is not extremely time critical,
Ada95 is more a broad systems-programming language that is
well suited for both portable application programming as well as
low-level bit fiddling, real-time signals processing, high performance
computing, and embedded applications with strict safety and
resource requirements, which were so far more the domain of C.

|> Ada software has _never_ failed?

Good Lord, of course not. You can screw up in Ada just as much as
you can screw up in any language. The nice thing about Ada is just
that the language requires compilers to immediately spot many
dubious situations for which you would have to buy very expensive and
still less reliable tools to detect them in other languages. An
experienced Ada programmer can use Ada's powerful subtype system to
proof various properties of code for which in other langauges
you would need very expensive dataflow analysis and verification
tools. This has made Ada95 or Ada subsets such as SPARK the languages
of choice in safety critical applications, such as military
systems and avionics, but also more recently in quite some financial
applications.

Ada just supports you well if you want to write very carefully
engineered and highly maintainable code. It certainly does not
force you to do so. No language could.

Markus

-- 
Markus G. Kuhn, Computer Laboratory, University of Cambridge, UK
Email: mkuhn at acm.org,  WWW: <http://www.cl.cam.ac.uk/~mgk25/>