"Alex Mizrahi" <[EMAIL PROTECTED]> writes: > PR> Which book? > Paul Graham's "On Lisp".
Oh ok, someone mentioned that was online, and I just bookmarked it. I'll look at it when I'm more awake. > "Programming Languages:Application and Interpretation" > Shriram Krishnamurthi > Brown University > > it's not Common Lisp but Scheme though, but it's very interesting since it > shows how continuations can be used for better web programming. Scheme probably makes more sense for this type of book--it's simpler than CL. > most CL implementation do tail call optimization, unless you're running > debug mode -- in that case you'd prefer full stack. I'd rather stick to what the CL standard says, rather than what some implementation might happen to do. CL does not guarantee TCO so these code transformation schemes mustn't rely on it. > optimizing language. i think it's called trampolined style. > example can be found in PAIP book: interpreter of Scheme is implemented in This book doesn't seem to be online. But anyway I think you mean, compile the Scheme code into one giant CL function, which is no longer really a clean mapping of Scheme to CL, it's just writing an interpreter. And I think that interpreter has to do its own management of environments rather than letting the CL runtime do it. So basically it says CL is turing-complete and can do everything, which we already knew ;-). > (defun drive-cps (cps-lambda) > (catch 'done > (loop for f = cps-lambda then (funcall f)))) Part of the problem I'm having with these examples is I don't know all the different macros being used. But I think I understand one part of what was confusing me before: your call/cc macros depend on a nonstandard feature of some CL implementations. You can't write a call/cc macro in standard CL--you instead have to write something that transforms the entire program. I think even with TCO though, you still can't do coroutines with CL macros (but you can do them with real call/cc). The point is that you have to do something like TCO on calls that are not tail calls and actually have to return. You again have to transform the whole program, not just expand a call/cc macro locally inside functions that use it. -- http://mail.python.org/mailman/listinfo/python-list
