So I got thinking about clojure pypy tonight, and got thinking how easy it would be to adapt my old code to run as a interpreter. So I pulled in a few files, implemented a few methods, and I have prototype running (+ 1 2) as interpreted lisp code.
I slapped it up on github...it's ugly, but it's a start: https://github.com/halgari/clj-pypy The idea here is simple. Every object in the VM must implement evaluate(self). Functions must then implement invoke(self, args). Most objects will simply return themselves when evaluate is called, there are some exceptions: Var objects return the result of evaluating their most recent binding Symbols find a var that corresponds to their name, and runs evaluate() on that Lists have the following code in evaluate(): def evaluate(self): f = self.first().evaluate() print "f = ", f args = [] h = self.rest() while h is not None: args.append(h.first().evaluate()) h = h.rest() return f.invoke(args) Basically lists evaluate all their arguments, then construct a arglist and pass the arguments to the first item in the list. The awesome thing about this is that this all would be quite expensive in most VMs, but the majority of this will be optimized away by the pypy JIT. I have to admit, I'm very excited about this project. PyPy's JIT goes bug nuts when it can work with immutable structures, I think we'll start to realize over time that the tracing JIT is a excellent fit for a LISP like language. And the fact that (at least in my vm) we don't have bytecode, this means that we can truly have code be the same as data. BTW...the code on github probably won't compile with PyPy yet. I just ran it in Python 2.7. I want to get the code in scratchspace.clj working first then I'll get it to run in RPython. Timothy -- “One of the main causes of the fall of the Roman Empire was that–lacking zero–they had no way to indicate successful termination of their C programs.” (Robert Firth) -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
