I have the feeling that I'm going to be repeating this for some time to come...
in reply to (A6) Perl 6, a general-purpose language?
There is a very important distinction to be drawn between typed values and typed variables. C only has typed variables; you can't look at an arbitrary C value and know its type. You can do this in Perl, that's what bless and friends are for. In Perl 6 we'll be getting a richer set of value types out of the box and I applaud that. We're also getting typed variables in Perl 6, and that's good too, for several different reasons:
Perl 6 also introduces a concept that I'll call, for the nonce, 'storage typing', which allows you to specify that a particular variable that looks like, say, a Scalar, is actually implemented by some arbitrary type that responds to the same interface as a Perl Scalar. This looks like being Perl 6's replacement for tying, and very nice it looks too.
- You will be able to define 'struct' in Perl that matches an equivalent C struct, which makes life so much easier for 'Glue' writers.
- If you want it (and I can't imagine why you would) you can go the whole bondage and discipline route and adopt strict typing throughout your code.
- Optimizers can make use of type declarations to improve performance, so you can opt to take B&D flexibility hit only in your inner loops (or at other points where a profiler shows you have speed issues)