Hello! Here's an update on pirate (the python to parrot compiler) from the trenches.
Pirate started as an example that fit in one small file and it stayed in that single file over the years while it grew into a *huge* mess: one monolithic object performing a variety of transformations on python's syntax tree, all in one single pass. Thanks to a Summer of Code grant from Google and the Perl Foundation, Curtis Hall and I have been working to refactor that mess. Our long term goal is to allow pirate to support multiple language front ends (for example, PyPy and Pugs) but our immediate goal was to make the refactoring easier to handle. So far, we've created a generic transformation module that greatly simplifies the work done by Visitors in the compiler module (it's called transform.py in the pirate repository - see below) With the generic Transformer in place, we were able to separate out a simplification pass, so that list comprehensions (eg: [x for x in range(10) if x > 5] which evaluates to [6, 7, 8, 9]) are converted into their corresponding for and if blocks up front, before PirateVisitor ever sees the tree. Curt is currently working to use this same principle to separate out function definitions from generator definitions, another chunk of the single-pass system that would work much better as a separate pass through the tree. The big questions we'v been dealing with, though, is "what will pirate look like after the refactoring?" Well, we think we have a good answer, and we'd like your feedback. We recognize that there are very few people out there that understand how pirate works *today* so what we've done is create a much simplified "toy" version of pirate and shown, though actual code, how that toy version can be refactored, all in one easy to read narrative python script. Hopefully, you'll be able to understand what's going on even if you're not a python developer. So... Without further ado, here is the plan: http://pirate.versionhost.com/viewcvs.cgi/pirate/toys/refactor.py?rev=HEAD&content-type=text/vnd.viewcvs-markup Or, if that's probably mangled: http://tinyurl.com/d92f3 It's short, contains test cases, and you can actually run it from python, or step through it with a debugger. It does *not* take us all the way to a language-neutral compiler, but it will make that step much easier. Anyway, Curt will be using this plan as a guide to actually implement as much of the refactoring as possible in the time he has left for the Summer of Code, so if you've got feedback, please share it on the pirate list: http://www.cornerhost.com/mailman/listinfo/pirate Other links: The priate home page is here: http://pirate.tangentcode.com/ The code for pirate is available for browsing here: http://pirate.versionhost.com/viewcvs.cgi/pirate/ Thanks for reading! Sincerely, Michal J Wallace Sabren Enterprises, Inc. ------------------------------------- contact: [EMAIL PROTECTED] hosting: http://www.cornerhost.com/ my site: http://www.withoutane.com/ -------------------------------------
