Hi all,
So I'm still thinking about a generic
wrapper for python modules. I would like
to be able to recompile the python standard
library (and other libraries) to run on parrot
with only a few minor patches.
I realize this is probably completely foolish,
but I'm lazy, so... :)
I've done experiments in the past running
PythonObjects outside the python VM. This
should be possible by replacing a few generic
routines that refer to the interpreter.
One of the major issues is garbage collection.
Python's VM does refcounting. There are two
macros it uses: Py_INCREF(x) and Py_DECREF(x).
They're pretty self-explanitory, but the docs
are here:
http://www.python.org/doc/2.4/ext/refcountsInPython.html
It seems to me that these macros could be
replaced with something that puts the objects
in the right place for parrot to deal with them.
I've read the memory_internals and pdd09_gc
docs but I'm still trying to understand how
this would work.
It seems that instead of looking at the *count*
of references, the DOD system actually walks
through the graph of references. So it seems
you could fake refcounting just by adding
references and removing pointers from
somewhere in the tree that gets walked.
So: Py_INCREF(x) could be rewritten to (for example)
append a reference to x in a parrot array,
and Py_DECREF(x) would pop it off the array.
Am I on the right track here? I'm sure this is
a very naive and inefficient implementation, but
I don't see why it wouldn't work. If it would work,
is there a better way?
Also, my understanding is that parrot uses only
a Mark and Sweep system. Is that correct? pdd09
describes the three general methods, but doesn't
say which one(s) parrot actually usess. memory_internals.html
seems to imply the mark and sweep system only...
Or does parrot do all three?
- Michal
http://withoutane.com/
