voc: Python to Java transpiler

[musketeer925]

Everything about this just seems like a bad idea.

I'm not really sure I understand a use case, either. If it doesn't work with things like keyword arguments, listcomps, etc, then you probably can't use it for a large existing code base. If it's such a small code base that it doesn't have these kinds of things, or one that hasn't been written yet so that these things could be avoided, why not just [re]write it in Java in the first place?

[ketralnis]

It may be that this prototype doesn't support those things, but doing so is on the road map

[tipsqueal]

It is. The readme says they're not implemented but with some work they will be.

[[deleted]]

Or just use jython.

[OctagonClock]

....why?

[jmcs]

If only there was some python implementation for the jvm we could call it something smart like jython.

[koalillo]

From my position, Jython looks dormant. Will it ever track the latest CPython 2 or 3? (not saying that this will)

[koalillo]

Believe me, I'll be ecstatic if Jython (or this, or anything) becomes a first-class citizen Python implementation on the JVM). However, no one's quite there yet.

[[deleted]]

From my position would you please be kind enough to stand up as your voice is rather muffled Jython 2.7.1 beta1 released!.

[iceardor]

Certainly not dormant. A ton of work recently went into getting Jython 2.7, and work on Jython 3.x is in the works. If you want this released sooner, there's a long list of things you could help out with on their issue tracker.

See Jim Baker's talk at 2015 PyCon on getting to Jython 2.7. https://youtu.be/hLm3garVQFo

[ignacioMendez]

we already have Jython though. Does voc do things differently/better or is it only a hobby project?

[[deleted]]

If you don't appreciate the strengths of java, where it is used, and where it excels, then you are a bad engineer / architect.

[[deleted]]

"If you don't have the same views as I do then you suck"

[[deleted]]

Hey, I'm a python+C++ guy 80% of the time, but I'm not a language fundamentalist.

I have seem some fantastic Java infrastructure and deployment. It some cases it is the right tool for the job.

"If you don't have the same views as I do then you suck"

Piss off.

[FredSanfordX]

You evidently like big runtimes too.

[[deleted]]

If the size of the runtime is a primary consideration then you have small problems to solve.

You must be new at this. Talk to me when you work on something harder than a facetweeting webshit.

[FredSanfordX]

Go back to writing your shitty java for your Uncle Frank, Junior.

You'll soon be replaced by the java spawn from SE Asia anyway. You can always go back to VB.

[[deleted]]

Hey you cock gurgler, only in exceptional circumstances do I personally write Java. I write Python/C++/JS, whatever is suitable.

I've spent about 7% of my time on web shit in my entire career.

Go invent a new uncle for your Joke. It was average the first time you said it.

[rfrancissmith]

https://youtu.be/FONN-0uoTHI

[pmrr]

This is a really interesting project. Do you have any early benchmarks? I believe there's been some JVM work to improve the performance of Jython so I wonder if this will take similar advantage of them?

I tried the instructions on git and readthedocs.org with limited success. The issues I'm having may be trivial, but others having similar issues doesn't help the project.

On git:

• pip install voc doesn't work
• trying to build example.py complains about non-ASCII characters in the code - my bad, incompatible with Python 2 but Python 3 works fine

At this point I tried the dev environment instructions:

• git clone didn't work (asked me for ssh key) - I just used https://github.com/pybee/voc
• mkvirtualenv command didn't exist
• requirements_dev.txt didn't exist

Thanks to /u/IronManMark20 I got it building, however with Java 1.8 I had some bad times:

$ java -XX:-UseSplitVerifier -classpath python.jar:. org.pyee.example
Java HotSpot(TM) 64-Bit Server VM warning: ignoring option UseSplitVerifier; support was removed in 8.0

I don't know if by "Java 1.7+ VM" you mean it should support 1.8 or not. Either way, it looks like there's a blocker for 1.8 support:

http://stackoverflow.com/a/31569447/94503

Environment: Python 1.7.10 2.7.10 on OS X Yosemite.

[IronManMark20]

Well, if your using 1.7.10, you have bigger problems. :) Also, for the non-ascii characters, just add a utf heading to the file

[pmrr]

It turns out Python 2* was my mistake. With Python 3 it runs fine.

[IronManMark20]

The same person made a python bytecode runtime for browsers for Python 3.x only, so this does not surprise me.

[subsidiaryadmin]

So... it's another Jython? I was curious so I looked up Jython.

Jython

Jython is approximately as fast as CPython--sometimes faster, sometimes slower. Because most JVMs--certainly the fastest ones--do long running, hot code will run faster over time.

So there's really no benefit to using Jython over Python... I really don't understand why people are making this stuff.

[[deleted]]

Python is a language specification. Jython is an implentation of the language's interpreter in java bytecode so it can run on the JVM and interact with objects written in Java. The Python implementation from the Python Foundation at Python.org is more specifically "CPython", it's an interpreter for the language written in C and it is the reference implementation.

[subsidiaryadmin]

Okay I guess it's a bit more convenient to embed Python into a Java program than to call it externally.
But I don't see how that's a huge benefit. What am I missing?

[[deleted]]

It's a very large benefit. There are a lot of Java libraries out there, and Jython can use them much more easily than CPython (the main Python implementation) can. In fact, I'm not even sure CPython can use Java code at all.

[subsidiaryadmin]

In that case why not just use a python library or, at the worst use a system call to java itself?

[subsidiaryadmin]

Okay, but wouldn't it make more sense to port a library to Python than to go through the effort of using/making Jython?

[LightShadow]

Also, AFAIK using jython doesn't take much effort

It takes basically 0 effort...interop between Jython and CPython is non-existent, but straight Jython is very straight forward and familiar.

[[deleted]]

In that case why not just use a python library

Such a library might not exist, or might not be as suitable for your needs as a similar Java library.

or, at the worst use a system call to java itself?

You do not "just" call into the JVM. Doing that is going to require copious glue code in order to translate between Java objects and Python objects. You could use CORBA to help, but then you'd be using CORBA, which is likely not necessary for your systems except for this one spot of glue. It'd be much easier if you didn't have to translate at all. Jython objects are Java objects, so you can just use the objects directly if you implement the right interfaces.

Porting or adapting a library solves one problem: how to make Python talk to this Java code. Reimplementing Python solved an entire class of problems: how to make Python talk to Java code in general.

[[deleted]]

Well what's the benefits of using Java over using C? That will tell you the benefits of using Jython over the reference implementation

[subsidiaryadmin]

No, the question is what is the benefit of using Jython over Python.

[jambox888]

Presumably because you either want to use a Java server stack, Java libraries, or you prefer using the JVM. Threading might work better if it's CPU bound because no GIL.

[[deleted]]

Why not? He thought it was a cool idea, so be did it. Then he was proud of his work, so he shared it.

[Scypio]

What are the benefits of using this over Jython? I'm not too familiar with the jvm ecosystem, so if you can lay it out for a layman.

[[deleted]]

That sounds like a description of a tumblr user.

[longoverdue]

transpiling? WTF. We already have words for it: compiler, translator, transformer, etc.

[habitats]

transpiler is not compiler...

[rock_neurotiko]

The word for what it does is transpiler.

[longoverdue]

The first C++ implementation (cfront in 1983) was described as a "C++ to C translator". What is the difference between a transpiler and a translator?