Dan, Why is there a callmeth op? Can't we just use a regular invoke as with other subs? Or does the callmeth op do both a find and invoke as an optimization?
Jonathan Sillito > -----Original Message----- > From: Dan Sugalski [mailto:[EMAIL PROTECTED] > > Nope, not objects, but at least it's partway there. This bit is about > making method calls. > > We've two issues on the front end. First, we need to be able to get a > method PMC from an object, in those cases where we want to save that > for later, and second we need to call methods. So, here's how we're > going to do it. > > We add three ops, findmeth, callmeth and callmethcc. (The latter just > automatically takes a continuation for the following op and stashes > it in P2, while the former assumes one has been put in P2 already) > They all find a method PMC based on the object and method name > already loaded. The call ops then call > that PMC's invoke vtable entry, which acts as normal. > > So the sequence is: > > P0 = P2->find_method(interpreter, P2); > > and for the call ops, then: > > dest = P0->invoke(interpreter, P0, expr NEXT()); > goto ADDRESS(dest); > > The returned method PMC handles anything fancy--multimethod dispatch > and whatnot. We need base engine support for MMD and method caching, > amongst other things, but we can get to that later. > > The method PMC returned by findmeth can be invoked as a regular > subroutine, so we're fine there. I'm not, at the moment, leaning > towards a separate "invoke this pre-fetched PMC sub as a method" op, > since we're not passing on any information as to how a PMC is invoked > outside of there being an object in P2, but I can be convinced > otherwise if we can make a good case for languages actually using > that information. > > I'm thinking at this point, since we need to add the call and callcc > ops as it is, that we should probably have tail versions of all these > ops, which just puts the various bits from the continuation in P1 > back before making the call, but we can talk about that later if we > want. > -- > Dan > > --------------------------------------"it's like this"------------------- > Dan Sugalski even samurai > [EMAIL PROTECTED] have teddy bears and even > teddy bears get drunk >
