Saturday, June 22, 2013

Camelia at Age 13: Perl 6 on the JVM Debuts

Perl 6 is now thirteen years old.  And she's very much a teenager in attitude, self-confident yet still growing up.  This contrasts with Javascript, which emerged from Brendan Eich's head, fully-formed like Athena -- but that only shared the Zeus-sized headaches with everyone until JQuery came along.

But Camelia, as she is fondly referred to by fans of Perl 6, is growing up fast.  Both too fast, and not fast enough.  To some of the community, the prospect of major changes to the language is scary.  Perl 6 is trying all of these crazy new things -- invariant sigils, metaoperators, grammars. She's even doing subroutine signatures, because "all of her friends are doing it".

They can't stay little children forever, you know.

And teenagers are liable to do surprising things.  So it was, that this week we announced Rakudo Perl 6 now runs on the Java Virtual Machine (JVM).  It's not perfect yet, but 62% of the files in the spectest pass as of yesterday.  Given the rate things are progressing, I'm sure it's already at a higher pass percent.

And yet, I'm sure there is no small number of you whose first thought about Perl on the JVM was "Heresy!".

There are certainly good reasons to support this point of view.  Startup times are horrible at this early stage, still O(seconds), and much of that is JVM's overhead.  It has well known security issues.  And of course the major implementation is controlled by $corporation, who just wants to make money off it.  And why would we want to abandon open-source VMs?

Still, there are plenty of good reasons for the port.  One is that the JVM is ubiquitous, and many devices have a copy pre-installed.  Most of Java's stability issues have been dealt with, and it serves Perl's competitors well enough through Jython and JRuby.  And it is well-documented, with bazillions of libraries (more than fooilions, anyway).  So we can finally address the longstanding desires of the community in things like sockets and threading, because we can tell the difference between our mistakes and those of the VM.

Instead of thinking of Perl 5 as a "sister language", I like to think of it as Camelia's father instead.  A father that might be kind of upset that she brought "that kind of language" into our house.  But she has a mind of her own, and I'm afraid that this won't be the only boyfriend she'll be bringing home.  There is a GSoC grant to build a Javascript backend to Rakudo.  And Niecza Perl 6 already uses the .NET Runtime.

However, Perl 6 is not abandoning open-source and C language implementations, either.  The announcement of MoarVM shows that Perl 6 developers plan to develop a lightweight VM specifically for NQP and Rakudo.  C functions will be directly callable within Perl itself, with the NativeCall interface.

Now, if Parrot fly off on its own course, that's Parrot's call.  You know how these teenage relationships go -- this could end up in a blow-up on the quad, or just as easily turn into hot makeup coding.  What, you didn't think I was going to say something that would violate the CoC, did you?

But Perl 6 is not done growing yet.  Camelia, like other teenagers, cares about fashion and wishes she had better threads.  And, once we get tuits, this is pretty high priority.  Because any modern language needs to live in the multi-core reality.  This is something that we can still design around,  that may not have recieved the same care ten years ago.  Many threading features are already baked into the language, like hyper operators and async blocks.

So I view the debut of the JVM port as Rakudo's real début, as with a debutante.  A treceañera, if you will.  I guess, given that she's 13, maybe it's a Bar Mitzvah -- except that she's not a boy, she's a butterfly.  But this is a chance acknowledge Perl 6's presence in the language scene.  Of course, these coming-of-age ceremonies don't mean the teenager is truly grown up yet. 

But grow up she will, and faster than some of you might like.  Perl 6 is rebellious, and changes things that those in her father's Perl 5 community don't understand.  But if you talk to the pumpkings, they sincerly hope that Camelia doesn't turn out exactly like her father.

After all, do we want keep the ithreads model?  Do we want to modules that dig into the compiler internals like XS does?  Perl 5 isn't perfect, we are just accustomed to its particular idiosyncrasies.

But for all that Perl 6 is different, she still loves her father.  We still have sigils, classes, @_ in subs (if you still want it), P5-style regexes, modules, and TIMTOWTDI.  It's still Perl.  Moreover, there are at least two efforts to run Perl 5 code in Perl 6 -- the v5 grammar/compiler in Perl 6, and access to libperl from MoarVM.  So the sky isn't falling on compatibility.

Nor is the other extreme true: Perl 6 development is in fact moving forward at a fast pace.  We know that Perl 6 is late.  Very late.  So late, in fact, that it's her father that's going to turn into a Pumpkin.  But when Perl 6 finally comes of age -- sooner than you think -- it will be something that the Perl community will be proud of.

And I apologize in advance for anything Camelia does in her bratty teenage years.


  1. So you can run Perl 6 on 3 billion devices now, right?

    1. In theory, yes. But Perl 6 requires Java 7's dynamic language features, so older devices are excluded from the total. And we certainly haven't test on that many devices. But in less than two years' time, that will almost certainly be true.