O'Reilly Open Source Convention - August 1-5, 2005

Session
Inside Ponie, the Bridge from Perl 5 to Perl 6
Nicholas Clark, Fotango

Track: Perl
Date: Thursday, August 4th, 2005
Time: 2:35pm - 3:20pm
Location: Portland 256
At its heart Perl 5 is a stack based virtual machine using reference counting to manage memory. Parrot is about as different as you can get--a register based virtual machine using mark and sweep to garbage collect memory. The intent of Ponie is to provide an upgrade path to Perl 6, by enabling existing CPAN modules to be used unchanged with parrot. To do this means taking the Perl 5 implementation and making the minimum changes possible to make it work atop Parrot.
The substantial differences between the internal architectures mean there is already a large gap to bridge. Add to this the fact that Perl 5 has almost no abstraction of the internal structures for extensions to use, and you realise that many of the most important modules on CPAN are calling APIs which assume a very Perl 5 like system. Then remember that Perl 5's reference counting gives timely destruction of objects, which lots of code relies on, and you start to realise that emulating all this on Parrot is no easy task.
Come to this talk to see just how Ponie is going about providing an emulation of the Perl 5 behaviour that XS code expects. The explanation of the systematic differences between the two architectures will teach you things you never knew about how Perl 5 works, give you insights into writing better code for interfacing to Perl 5, and show how to target Parrot natively in the near future.