7 ms·

I agree with you, but out of interest: how would you do it? I'd be tempted to ask "why distinguish between vcalls and normal calls?", but in general I don't th

• jey 17y ago
  Simplest approach: add a parameter to the call-dispatch machinery. For example, let's say you have functions op_call() and op_vcall() corresponding to the bytecodes or AST nodes representing normal calls and vcalls respectively, and these methods work by calling the lower-level internal method dispatch_call(). What they're doing right now is having call() and vcall() set a global that is then inspected later on by dispatch_call() to select the correct error to raise. I'd say that the better thing to do is to leverage the call stack and just turn it into a parameter that's passed to dispatch_call(). That way you can't forget to set it before dispatch_call(), and you get cleanup for free when the stack gets unwound. (Even if you end up longjmp()ing out of the call due to an exception or whatever!) I'm sure the above is a simplification of the actual scenario in MRI, but I bet the same general schematic can be applied, even if the implementation details are a bit more complicated in a real-world interpreter like MRI.