Typed Python?

[Dominic]

First of all, thank you very much for
your detailed summary about Yahoo Store
and it's connection to Lisp.

 >That large, robust production systems could be developed in a dynamic 
 >language without being dragged down by poor performance. This went 
 >against the current ethos that said that dynamic languages were only
 >any good for prototypes but you would have to convert to a real
 >language (C, C++ or Java) because dynamic languages would not scale.

Isn't this mostly an architecture dependent issue?
Python is certainly slower than plain C/C++, so that
you have to be more careful. Even if parts are done in
C/C++ partitioning is not a trivial undertaking by itself.
I see Python's or Lisp's advantage in the possibility to
prototype different architectures more quickly. After
evaluation  a final system could then be implemented
in Python/Lisp + some C/C++ code for example.

Ciao,
  Dominic