[Python-Dev] Re: Python 2.0 and Stackless (original) (raw)

Just van Rossum just@letterror.com
Sat, 05 Aug 2000 09:03:33 +0100

[ CC-d to python-dev from c.l.py ]

Jeremy Hylton wrote:

It is a conservative response. JPython is an implementation of Python, and compatibility between Python and JPython is important. It's not required for every language feature, of course; you can't load a Java class file in C Python.

Jeremy, have you ever looked at stackless? Even though it requires extensive patches in the eval loop, all additional semantics are nicely hidden in an extension module. The Java argument is a very poor one because of this. No, you can't load a Java class in CPython, and yes, "import continuation" fails under JPython. So what?

I'm not sure what you mean by distinguishing between the semantics of continuations and the implementation of Stackless Python. They are both issues! In the second half of my earlier message, I observed that we would never add continuations without a PEP detailing their exact semantics. I do not believe such a specification currently exists for stackless Python.

That's completely unfair. Stackless has been around much longer than those silly PEPs. It seems stackless isn't in the same league as, say, "adding @ to the print statement for something that is almost as conveniently done with a function". I mean, jeez.

The PEP would also need to document the C interface and how it affects people writing extensions and doing embedded work. Python is a glue language and the effects on the glue interface are also important.

The stackless API is 100% b/w compatible. There are (or could/should be) additional calls for extension writers and embedders that would like to take advantage of stackless features, but full compatibility is there. To illustrate this: for windows as well as MacOS, there are DLLs for stackless that you just put in the place if the original Python core DLLs, and everything just works.

Christian has done an amazing piece of work, and he's gotten much praise from the community. I mean, if you are looking for a killer feature to distinguish 1.6 from 2.0, I'd know where to look...

Just