Re-executing the code object from a class 'declaration'
aleaxit at yahoo.com
Wed Oct 6 22:38:40 CEST 2004
Carlos Ribeiro <carribeiro at gmail.com> wrote:
> > Nope, f doesn't get the bases AT ALL; the bases (as a tuple) go in only
> > when you call the metaclass.
> Well. I was mistaken (and that's not be the first time). It goes like
> this; I first checked the dis.dis() code:
> 27 64 LOAD_CONST 4 ('MyClass')
> 67 LOAD_NAME 7 (object)
> 70 BUILD_TUPLE 1
> 73 LOAD_CONST 5 (<code object MyClass at
> 0120A0A0, file "c:\work\help-on-c-l-py\re_exec_class.py", line 27>)
> 76 MAKE_FUNCTION 0
> 79 CALL_FUNCTION 0
> 82 BUILD_CLASS
> 83 STORE_NAME 8 (MyClass)
> ... with that build_tuple there... besides that I knew I *can* access
> the bases from within my class statement body:
> class MyClass(MyBaseClass):
> bar = MyBaseClass.foo
> ... so I had suspected that the bases *were* passed to f(). But wait!
> Actually, Python is building the stack for the BUILD_CLASS opcode.
Right. When you mention MyBaseClass in the body, it gets looked up in
the globals, just where it was looked up when you passed it as a base.
The 0 in MAKE_FUNCTION _and_ CALL_FUNCTION opcodes refers to the number
of arguments to the function, btw...
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