Okay, here's a quick draft of the rules I'm thinking of to govern memory
allocation and tracking so the interpreter can GC and dead-object detect
properly.
1) The pointer in a PMC structure may point to:
*) Another PMC
*) A buffer object
*) Something non-tracked
Additionally the buffer object may contain array of buffer object pointers,
or an array of PMC pointers. Flags in the PMC note these occurrences.
2) A buffer object has the structure:
struct {
void *memory;
INTVAL size;
}
this may be at the head of a larger structure, that's OK. (In fact, this is
the start of the STRING and BIGNUM structures) The memory pointed to by a
buffer object may be anything, but it is assumed to be moveable.
For a buffer to be considered 'live' it must be pointed to by a PMC either
directly or via a single level of indirection. (If the PMC points to a
buffer object that has an array of buffer pointers in it) For a PMC to be
considered live it must be reachable via the interpreter's root set.
There will be a mechanism to register PMCs with the interpreter to note
they're pointed to by something that the interpreter can't reach. (For
example, a structure in your extension code, or via a pointer stashed in
the depths of a buffer object, or referenced by another interpreter) This
"foreign access" registry is considered part of an interpreter's root set.
Dan
--------------------------------------"it's like this"-------------------
Dan Sugalski even samurai
[EMAIL PROTECTED] have teddy bears and even
teddy bears get drunk
