Yes.
At a Perl conference in October last year Stefan Seifert decided it was time for him to have a go at something Perl 6 related. He had never written Perl 6 code before, let alone participated in the project, but within 24 hours he had Perl 6 calling Perl 5 calling Python[1].
That was just a few months ago. Now the Inline::Perl5 module[2] allows folk to use Perl 5 modules, even ones that do C level guts poking in to the Perl 5 interpreter, and to pass data back and forth, do callbacks back and forth, handle exceptions raised by Perl 5 in Perl 6 and vice-versa, use Perl 6 to call methods on Perl 5 objects and vice-versa, and use Perl 6 to subclass Perl 5 classes. Thus he's been able to, for example, create apps in Perl 6 using a leading Perl 5 web framework called Catalyst.[3] He's also having fun with calling Python libs from Perl 6.[4]
There's a lot more going on related to interop between Perl 6 and Perl 5, and more generally between Perl 6 and other languages, but the above is obviously a biggie.
> Is it even possible to convert existing Perl5 CPAN packages to support both versions at the same time
As is hopefully clear, with Inline::Perl5 there's no need to convert.
(Some folk will still want to rewrite some Perl 5 code in to Perl 6, and there are fledgling tools to assist, but they aren't necessary, just a nice option to have.)
[1] https://www.youtube.com/watch?v=m_Y-lvQP6jI&list=UU7PuZDAIVM...
[2] https://github.com/niner/Inline-Perl5
[3] http://www.reddit.com/r/perl6/comments/2k6ii8/nines_apw_talk...
[4] http://www.reddit.com/r/perl6/comments/2n27el/perl6_20141121...
But Python3 is an obvious failure and no one is admitting it, yet. I've seen claims from the core dev team about how Python3 is doing well because it has more downloads from Python.org, which is so stupid I won't even address it. A comparison of PyPI download statistics says it all.
Python3 migration had many ridiculous ways of pushing people to migrate. The answer for Python3's adoption was always something new. It reads like the list of reasons for invading Iraq.
Originally (and today's) overly optimistic EOL for Python2, then automated code conversion utilities, then porting all the major libraries, then 'six' type libraries to allow an ugly PythonX middle ground, then adding 3.x-only new features as a carrot, now the bright idea from the core dev team is to focus on pushing Python3 as the default install on distros. They all failed. Python3 as default on most distros won't do anything either.
All that said, and I think this is the best-case scenario: Python3 will survive and eventually thrive. It will just be a shadow of Python's former glory.
Is that -really- worth forcing unicode handling? For Zeus' sake, I wouldn't think so. This coming from someone who agrees with the change in theory.
I dunno. I'm new to Python (version 2 so far) and I easily spend 25-50% of my coding time fighting with ascii/unicode issues in Python. I wish Python 2.x just did something smarter.
Similar, but not quite as bad, is the need for me to put str() around non-string values in concatenation. Just f'ing doing it for me. I'll write a bunch of code, put together a message in a concatenation only to have it blow up at run-time because of this.
sigh I really miss Perl's implicit behaviors sometimes.
I dunno, maybe this all is making me a better programmer and person, forcing me to really deal with Unicode now, and breaking me of lots of Perl bad habits. But it's really one of the sucky parts of the language.
There's some days, after spending half the day fighting with this issue, that I almost decide to dump the whole thing and switch to Python 3.
I'd probably agree 3.x is more Pythonic in this regard, but I think it was an ill-advised move. Plenty of reasoning in my last response as to why.
Why not go ahead and use Python3, you may find it works for you. For me, there's a long tail of libraries that don't exist there, and frankly following the core dev teams' example- we should all act in our own best interests. I'm far more productive in 2.x.
I may eventually move to 3.x, but it will have to be based on its merits. Rather than dogma, salesmanship or propaganda. Today it isn't even close to 2.x and we're nearing 7 years since 3.0 was released.
Unlike most things in life such as updating some software package, the "latest version" of a programming language isn't always in your best interests. I think this is a hard mental barrier to break down, especially people coming into Python now.
But I would always recommend learning/using 2.x, not only is it easier to build cool things with it (the whole point), but you have to learn 2.x. You can avoid 3 entirely, without any issue whatsoever.
I hear a lot of complaints about Python 3, but in my (limited) experience, 3 is better than 2.X in practically every situation I've experienced. But I've never had to maintain anybody's old code in it, either.
So are you saying that it's clearly "pulled ahead" in the race? Or that Python 3.x is a significant regression? Your "technological churn" comment makes it seem like you think it's just treading water, which I would interpret to mean a lack of progress vs. a step forward (or back).
'%s %s' % ('hello', 'world')
I'd recommend going for Python 3 unless there's a specific reason (library) keeping you on 2.
'{} {}'.format('hello', 'world')
"%s %s" % blah
I never had too much of an issue with Perl's implicit behaviours, but it enables some really lazy programming, even from (otherwise) smart people that are gung-ho about Modern Perl. E.g.:
sub { map { "$_ $_[0]" } @{shift->[0]} }
There's also stuff like this[1] for Perl + Unicode. :^P
[1] https://stackoverflow.com/questions/6162484/why-does-modern-...
There's an awful lot of FUD and hate for Python3 on Hacker News, but I've found it's great for a green-field project. And folks with 500KLOC existing systems should know that their technology choices are basically locked in time to when they started the project, anyway.
As far as I can see, python 3 is there now; it's the default on my servers, all the libraries support it, and it's a nicer language to program in. And just as that became true, everyone started losing their minds.
Yup, this was a gradual process, but by now everything I need is ported, even Django.
> now the bright idea from the core dev team is to focus on pushing Python3 as the default install on distros. They all failed. Python3 as default on most distros won't do anything either.
It worked on me: When Arch Linux made it the default I figured it was finally time to adopt it for my various everyday utility scripts, which resulted in me successfully pushing for it at work as the implementation language for several projects.
Respectively: Not at all, and not without major contortions. The languages have diverged a lot; even basic tasks like defining a function are not the same.
While not quite the same as what was asked, it's clear that 'not at all' is not an informed answer
But Inline::Perl5 is a completely different animal. It handles modules using XS or whatever fine. See my nearby comments for further details.
You are mistaken. See my nearby comment about Inline::Perl5.
> not without major contortions [can one convert].
One doesn't need to convert (due to Inline::Perl5).
That said there can be valid reasons (eg having fun and learning Perl 6) to want to convert existing Perl 5 code to a Perl 6 equivalent anyway. While some partial P5-to-P6 conversion tools already exist[1] (and I'd be surprised if more don't arrive in the future[2]), conversion of a well written Perl 5 module in to a well written Perl 6 module is mostly a manual exercise.[3]
> even basic tasks like defining a function are not the same.
sub foo ($foo, @bar) {
my $qux;
# do something
return $qux
}
Could you provide some code to illustrate what you mean?
---
[1] http://www.perlito.org/perlito/perlito5to6.html Incomplete but better than nothing.
[2] https://github.com/rakudo-p5/v5/ is a project to create a Perl 5 compiler written in Perl 6. It parses Perl 5 code and spits out Perl 6 ASTs. It's obviously not a huge jump for it to spit out straight Perl 6 code. One day...
[3] http://jnthn.github.io/css-tiny-presentation/presentation/#/
sub foo {
my ($foo, @bar) = @_;
...
}
As a practical programmer, I have enjoyed signatures and run-time type checking for years, provided by libraries. Even now, these libraries are more featureful than core signatures.
So, to recap:
> Can one even use CPAN with Perl6?
Yes.
A Perl 5 coder might write:
use Data::Dumper;
print Data::Dumper->Dump([1]);
use Data::Dumper:from<Perl5>;
print Data::Dumper.Dump([1]);
(Another important `from` option in Perl 6 that's currently being brought up to production grade is `:from<Java>`.)
The `.` rather than a `->` in the print statement line is another giveaway that this is Perl 6 code. And the `[1]`; is that a Perl 5 or a Perl 6 array literal? It doesn't matter. This line is a taste of how slick Perl 6 interop magic is. You barely notice it, but the language is automatically marshaling data and objects back and forth between languages as necessary.
Of course, the above is a trivial example. But that's not because complex examples don't work; within a few weeks of starting Inline::Perl5 its author Stefan Seifert was demoing a Catalyst app written in Perl 6. That needed fancy stuff beyond mere passing objects back and forth; in this case Perl 6 code had to subclass a class from another language, in this case Perl 5, and have Perl 5 accept objects made with the subclass as if they were Perl 5 objects made from a Perl 5 subclass.
Inline::Perl5 hasn't yet been smoke tested with all 130,000 CPAN modules, and it will no doubt fail with a few, and a similar story applies for the even more immature support for calling Java libs, but this tech ought to be a game changer, at least within the Perl community.
> Is it even possible to convert existing Perl5 CPAN packages?
There's no need. (See previous point.)
But if you really want to, then yes it is possible, and seems to be enjoyable. Reports I've read of P5-to-P6 conversion stories tend to express satisfaction that basic syntax is generally the same, the changes that are necessary make sense, and the final code is a lot shorter, often half the length, and is very readable.
It's not all roses with Perl 6. There's plenty to bitch about. (#1 is still speed.) But use of CPAN modules, and writing Perl 6 code alongside Perl 5 code, are quickly shifting over to the strengths column for Perl 6, not the weakness one.
P6's speed is still well behind Perl 5, but it's catching up very, very quickly.
And performance improvements won't stop there: https://fosdem.org/2015/schedule/event/perl6_beyond_dynamic_...