Forgive me if I am overlooking something really obvious, but while we're
almost on the topic, what is it prevents one from doing ordinary message
sends from C code by having the equivalent of the exact bytecodes of a
message send as a sequence of (Slang-generated) C code? This is what I
thought that exception code was doing when it triggers a method for block
unwinding or something.

Is it something like the interpreter not being reentrant?

Henrik