andreas.raab at gmx.de
Tue Jun 6 01:17:58 UTC 2006
Another one of the issues I really need a solution for is simple
callback support into the interpreter. For me, the simplest thing to do
that can potentially support all the relevant use cases is to merely
provide an interface that (via setjmp/longjmp) ensures that the C
callstack remains in order, e.g., prevents returns "through" other
I'm thinking about an interface like here:
int interpretEnter(int *cbID);
- (Re-)Enters the interpreter. Different from interpret() in such
that it creates an environment (via setjmp) to return to. Fills in the
cbID with an ID that is used in the return call.
int interpretExit(int cbID);
- Returns from a previous call to interpretEnter() with the
provided callback ID.
Both of the above functions may fail - interpretEnter() would fail if
for some reason the interpreter cannot be entered (no setjmp/longjmp
support, or failure to allocate jmpbuf). interpretExit() would fail if
the callback ID is not the last "matching" ID.
Note that the above does NOT make any assumptions on the means by which
the VM gets notified about the occurrence of the callback itself nor any
arguments etc. It is up to the plugin to provide that information by its
Question: Does anyone have a problem with the above? I'm trying to
design "just enough" so that projects like wxSqueak or others can
cooperate without knowing too much about each other.
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