Guido> The PVM doesn't have a lot of knowledge about types built into Guido> its instruction set.... The opcodes are mostly very abstract: Guido> BINARY_ADD etc.
Yeah, but the runtime behind the virtual machine knows a hell of a lot about the types. A stream of opcodes doesn't mean anything without the semantics of the functions the interpreter loop calls to do its work. I thought the aim of Eric's Parrot idea was that Perl and Python might be able to share a virtual machine. If both can generate something like today's BINARY_ADD opcode, the underlying types of both Python and Perl better have the same semantics.
Yeah, but the runtime could offer a choice of data types -- for Python code the constants table would contain Python ints and strings etc., for Perl code it would contain Perl string-number objects. Maybe. --Guido van Rossum (home page: http://www.python.org/~guido/)