7 ms·

PythonJS now faster than CPython

138 points by tyrion 12y ago

chubot 12y ago
Can it run real programs (i.e. not benchmarks)? If so I will be impressed. Glancing over the code, it looks pretty short, and I can imagine benchmarks will run, but not real programs. https://github.com/PythonJS/PythonJS/blob/master/pythonjs/pythonjs.py https://github.com/PythonJS/PythonJS/blob/master/pythonjs/py... It's true that most programs don't use all the dynamism of Python, but they probably depend on something that does (e.g. Django). Python is more dynamic than JavaScript, in that it has __getattr__, __setattr__, __getitem__, etc. If not, it's not fair to compare it to PyPy... PyPy actually runs arbitrary Python programs.
- belandrew 12y ago
  > Python is more dynamic than JavaScript, in that it has __getattr__, __setattr__, __getitem__, etc. No, it's not. You can do equivalents to all of those in Javascript. Javascript objects are all mutable with a few exceptions. They are just maps of properties, very similar to Python's. Properties can be added or changed at runtime. For example, setattr(obj, item, value) in python is basically just obj[item] = value in js.
  - craigyk 12y ago
    I think he meant that you can overload operators in python and not javascript... but yeah I agree with you. At the end of the day javascript is still just as, or more, dynamic than python.
  - pygy_ 12y ago
    __getattr__ and friends allow to customize the getters and setters. JavaScript is in the process of getting similar capabilities with Harmony proxies, but the spec has yet to be finalized: http://wiki.ecmascript.org/doku.php?id=harmony:direct_proxies http://wiki.ecmascript.org/doku.php?id=harmony:direct_proxie...
    - jonpacker 12y ago
      I'm slightly confused by your wording but I think the functionality you're referring to is already available via Object.defineProperty's "get" and "set" options: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
      - pygy_ 12y ago
        Object.defineProperty allows to overload get/set for a single key at a time. Harmony proxies catch everything, and really overload the getter/setter mechanism.
  - bcj 12y ago
    My JS knowledge isn't great. In python, I can do operator overloading such that `obj[item] = value` does something completely different than assignment. Is that possible with JavaScript?
    - jonpacker 12y ago
      You can set a custom getters and setters, but I wouldn't call it operator overloading. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe... So... > var x = {} > Object.defineProperty(x, 'value', { get: function() { return 1 }, set: function() { console.log('set') } }) > x.value 1 > x.value = 2 set > x.value 1
  - spankalee 12y ago
    No, JavaScript does not have Python's __getattr__, and obj[name] is not a substitute for it. obj[name] works if you have already either assigned a value for that name, it exists in the prototype chain, or you have defined a getter via Object.defineProperty(). It's truly no different than obj.name[1] - `name` has to already exist in some form. Python's __getattr__ [2] takes the attribute name as an argument, so it can be used to implement property access for any name, even those not known ahead of time. Ruby has something similar with method_missing, and even more with define_method and instance_eval. Dart has noSuchMethod. These are possible to implement in compile-to-JS language, but tricky to make fast. Dart's static analysis looks for all names that could be called on objects with a noSuchMethod, tries to figure out the most specific class it can add them to, then adds stubs to the JS prototypes to redirect to noSuchMethod(). A compile-to-JS Ruby could implement define_method easily enough, but method_missing is would be impossible to do the way Dart does it due to the open classes: you could dynamically add method_missing and not have the stubs available. If you want full Ruby semantics you have to abstract away method calls, which will be slow. I'm guessing the same problem exists for Python, so I wonder the same thing as the grandparent post: did they implement __getattr__ fully? [1] With the small difference in the names that are allowed. [2] https://docs.python.org/3/reference/datamodel.html#object.__getattr__ https://docs.python.org/3/reference/datamodel.html#object.__...
    - bretthartshorn 12y ago
      PythonJS implements __getattr__. See these regression tests: https://github.com/PythonJS/PythonJS/blob/master/regtests/class/__getattr__.py https://github.com/PythonJS/PythonJS/blob/master/regtests/cl... https://github.com/PythonJS/PythonJS/blob/master/regtests/class/mi__getattr__.py https://github.com/PythonJS/PythonJS/blob/master/regtests/cl... __getattr__ and __getattribute__ are implemented in the special __get__ function defined in: https://github.com/PythonJS/PythonJS/blob/master/pythonjs/runtime/pythonpythonjs.py https://github.com/PythonJS/PythonJS/blob/master/pythonjs/ru...
- euank 12y ago
  Javascript (6) has those in the form of Proxies [0]... Coming soon! I think that they cover the set of features you indicate anyways. However, you can already hack them in and there are multiple js projects that let you compile ES6 down to ES5, proxies included. As other commenters noted, python is not "more dynamic" than javascript. You can easily transform python code that does unusual metaprogramming stuff to javascript code that does similar metaprogramming stuff but looks significantly different; basically all languages that support runtime-eval will let you imitate all other metaprogramming features in a somewhat verbose fashion. [0]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
  - chriswarbo 12y ago
    > However, you can already hack them in and there are multiple js projects that let you compile ES6 down to ES5, proxies included. Of course, but will it still be as fast? For example we can trivially turn a Python expression "a + b" into a Javascript expression "a + b" to get a great speed benefit. It may even give correct results in benchmarks, but in general it breaks the semantics and therefore any frameworks which rely on it. FYI in Python "a + b" is equivalent to "a.__add__(b)", and hence the correct Javascript would look more like "a.__add__(b)", but this requires a property lookup and a function call so a lot of the speed gains may be lost (although some benefits may be regained by JITting). Considering that the parent pointed out how small this project's codebase is, it does give legitimate concern about how many rules there are for mapping Python's semantics to Javascript's. For example, the ShedSkin project has been around for years and gets very impressive benchmark results since it compiles Python to C++; however, it tries to map Python classes directly to C++ classes, which breaks the semantics immensely.
    - lclarkmichalek 12y ago
      It's even more complicated than a.__add__(b), due to __radd__: https://www.inkling.com/read/learning-python-mark-lutz-4th/chapter-29/right-side-and-in-place https://www.inkling.com/read/learning-python-mark-lutz-4th/c...
    - 12y ago
- bretthartshorn 12y ago
  pythonjs.py is not the main part of the translator. PythonJS translates in two steps, most of the translation happens in the first stage, in python_to_pythonjs.py https://github.com/PythonJS/PythonJS/blob/master/pythonjs/python_to_pythonjs.py https://github.com/PythonJS/PythonJS/blob/master/pythonjs/py...
JeremyBanks 12y ago
I also wrote an interpreter, and it's 500x faster than CPython or PyPy. (As it happens, my interpreter can only run a single fixed program, but I'm not worried: most people won't read past the headline when I announce it.)
- maaaats 12y ago
  Did you have a point?
- coldtea 12y ago
  >I also wrote an interpreter, and it's 500x faster than CPython or PyPy That's great! Even if your new interpreter doesn't run all the code that's out there it can serve as a base for further work, it's a nice proof of concept and it's just plain cool hacking. It certainly beats all those people merely posting snarky comments on project announcements. >(As it happens, my interpreter can only run a single fixed program, but I'm not worried: most people won't read past the headline when I announce it.) With sarcasm off now, yeah? They worked on something and they are enthusiastic about the results they get. Perhaps they want to oversell them, in a headline. So what? If people "won't read past the headline" then they also won't be using this PythonJS. So no harm done to them. At worst, you'll be lured to read an interesting article. And if you have any understanding of compilers/interpreters at all, you'll know before the end of it who real-world-usable it would be or not.
  - zobzu 12y ago
    This kind of thinking generally hurts more than it does good. Large amounts of people will register it in their memory as CPython bad, PythonJS, or really, anything else good. Don't know why, don't know why it's FUD, etc. Next time when they get a choice, they'll bash CPython. Not figuring why everyone uses CPython probably. And you're encouraging that. Probably just thinking it puts you on a higher pedestal or something of the sort. I think its pretty shitty.
    - lucian1900 12y ago
      Well, CPython is embarrassingly slow. The damaging thing is claiming things like PythonJS are implementations of Python, when they merely share syntax and some semantics. They might be fast, but that's not very relevant. Runtimes like PyPy is where we should be looking, since they implement the full Python language and are fast.
WizKid 12y ago
According to the footnote he tested with pypy 1.9. There was just a post here a day or two ago that pypy 2.3.1 was release. Seems like one should at least use the latest version when testing. Pypy 1.9 was release 2 years ago.
- srean 12y ago
  Yes, but am quite happy and impressed to see how well Pypy is holding up. Something that I have learned about reading benchmarks is to pay attention to who is coming consistently second. Usually that is the most informative part of a benchmark.
vomitcuddle 12y ago
If this project gains more traction, maybe it will get more people interested in Dart. (which is essentially javascript with a standard library reimagined for the things people are using javascript for today: async APIs, stream processing, mapreduce, webapps, etc.)
- deleted 12y ago
  [deleted]
- shadowmint 12y ago
  Nothing wrong with Dart (other than lack luster adoption) but I'm not sure a surge in interest of people using it as a dropin backend for compile-to-javasvript targets is really going to drive the sort of developer adoption you'd really be looking for.
rch 12y ago
This just translates Python syntax into JavaScript, assuming a direct translation is possible. Neat, but a more compelling post would compare with CoffeeScript and check build times, high-level syntax, and features like generators, list comprehensions, itertools, functools, and so on. Edit: why the downvote? Am I incorrect about something? If so, I'm genuinely curious to know what I'm overlooking here. Edit 2: I went over to the github page and it is in fact a 'transpiler', though it can run self-hosted in node, and the features list includes both list comprehensions and yield (i.e. generator functions). It looks like the itertools and functools libraries aren't supported yet, but doing so really wouldn't be too difficult. CoffeeScript is a direct output option too.
- Pacabel 12y ago
  Don't worry about the downvotes. Things have gotten pretty bad around here lately, especially after the whole "downvote if you disagree" policy was encouraged. A lot of totally correct and perfectly valid commentary ends up getting downvoted these days, often with no attempt made to explain why. It's particularly likely to happen when members of the Mozilla, JavaScript or Rust communities are involved. They're particularly sensitive to anything that might contradict their beliefs, and apparently they're particularly eager to downvote, for whatever reason. These days, many of us have started to read all of the downvoted comments. Aside from occasional spam, they're often among the most insightful comments in any given thread.
  - dbaupp 12y ago
    > often with no attempt made to explain why. It's particularly likely to happen when members of the Mozilla, JavaScript or Rust communities are involved Your repetitive comments about Rust's instability almost always receive a lot of feedback about why they are incorrect and/or invalid.
    - Pacabel 12y ago
      The Rust mis-votings are quite absurd. In no way can Rust be considered "stable". The most recent version is 0.10 (that is, it's still very pre-1.0), it's undergoing significant breaking changes on an ongoing basis, and even its home page warns that "Rust is a work-in-progress and may do anything it likes up to and including eating your laundry." Anyone who points out that Rust is just not stable yet is absolutely correct. Anyone who points out that it's looking unlikely that it will be stable before the promised end-of-2014 deadline for 1.0 is also correct. It doesn't matter who points out these facts, or how many times they do so. The facts are still facts, and whoever expresses them is totally correct. My suspicion is that the inappropriate downvoting is just immaturity on the part of the Rust developers. I realize that it can hurt to face valid criticism of one's work, but an important part of being a professional adult is to consider such criticism rationally, and to learn how to improve based upon it. Engaging in censorship of facts, however, completely contradicts with self-improvement. It renders the voting system useless when it's incorrectly used to censor others, due to a lack of emotional control on the part of the person misusing the system. It's one thing to downvote blatant commercial spam that has no inherent value. It's harmful to downvote perfectly legitimate commentary that you may just happen to disagree with, however.
chuckup 12y ago
The other interesting and recent "Python in the browser" project is RapydScript - https://github.com/atsepkov/RapydScript https://github.com/atsepkov/RapydScript Unlike PythonJS, it does not have the goal of being 100% Python compatible, but instead takes the CoffeeScript approach. So, like Coffeescript, you get (mostly) clean Javascript output, no huge library dependency, runs nearly as fast as Javascript, etc. Check out the "ants" demo - http://salvatore.pythonanywhere.com/RapydBox/default/editor http://salvatore.pythonanywhere.com/RapydBox/default/editor I've been playing around with both PythonJS and Rapydscript, and I like both. Different goals. PythonJS can output to Lua, too - so there's the whole Python in LuaJIT angle which could be very interesting as it matures.
- amirouche 12y ago
  Still, it's written in JavaScript. Not aiming full compatibility is not only humility. They can't do it.
zorbo 12y ago
Ah yes, the old X is faster than Y pointless nonsense. Let's ask the basic questions that always come to mind: - Does X do all or at least most that Y does? - Are the benchmarks sane? I.e. not the pointless arithmetic fibonacci that nobody really uses, but the useful stuff such as regexps etc.
spullara 12y ago
Near as I can tell, because CPythong is so tied to native code at every turn, none of the other VMs have any real chance of success without bridging to them.
- VeejayRampay 12y ago
  Also a big Ruby problem.
- lucian1900 12y ago
  cffi has been getting more popular lately, though, and it works on both CPython and PyPy. Hopefully this will slowly fix itself.
- Shish2k 12y ago
  Nice to see I'm not the only one who has a habit of accidentally adding a "g" on the end of "python". Still no idea why that happens though...
pfraze 12y ago
Python in the browser would be pretty fun. Congrats on the speed improvements.
anilshanbhag 12y ago
PyPy uses JIT to generate optimized code during runtime. As many comments noted, PythonJS may not support all Python features but still don't understand why PyPy performing worse than PythonJS.
- amirouche 12y ago
  You know JIT? I mean does it scale to run the JIT in the browser? I will say maybe. All people that do compiler stuff I asked the question think that it's not.
- lucian1900 12y ago
  Because PythonJS is not an implementation of Python, it merely looks like Python. It's easy to make a significantly simpler language faster.
zzleeper 12y ago
Nitpick: vertical text is really hard to read, sp if the image is compressed like that. Next time please use some bars instead of columns! Asides from that, this looks quite promising!
bayesianhorse 12y ago
PythonJS might win importance if there was a framework to build webapps with it. Otherwise it's only a curiosity...
millstone 12y ago
Python has bignums by default. I was curious how PythonJS implemented bignums, so I tried it, and the answer is: it doesn't. It just uses ordinary JavaScript doubles. This is a critical difference that ought to be called out, especially in the "add" micro-benchmark, which is measuring two very different things in the two implementations.
- bretthartshorn 12y ago
  PythonJS has support for 64bit integers using the Long.js library. You just need to type your variable as "long". Numbers larger than 64bits could also be supported with another library and simple modifications to the translator. http://pythonjs.blogspot.com/2014/06/64bit-integer-long-type.html http://pythonjs.blogspot.com/2014/06/64bit-integer-long-type...
coherentpony 12y ago
It'd be interesting to see a comparison with CPython with the 'numpy' backend using a vectorised code.
- bretthartshorn 12y ago
  Here is a new benchmark testing PythonJS using SIMD vectorized code in the DartVM vs CPython with NumPy. http://pythonjs.blogspot.com/2014/06/pythonjs-simd-vectors.html http://pythonjs.blogspot.com/2014/06/pythonjs-simd-vectors.h...
pandler 12y ago
I'd be interested to see how it stacks up against other python-to-js converters in terms of both speed and supported python features.
SnowLprd 12y ago
The comparisons to PyPy would be much more meaningful if they weren't based on a version of PyPy that's over two years old: PyPy 1.9 was released in 2012.
- amirouche 12y ago
  You mean 1.9 is not the last stable PyPy?
- bretthartshorn 12y ago
  I've posted updated benchmarks with the latest PyPy 2.3.1 http://pythonjs.blogspot.com/2014/06/pythonjs-faster-than-cpython-part2.html http://pythonjs.blogspot.com/2014/06/pythonjs-faster-than-cp...

138 points by tyrion 12y ago

Can it run real programs (i.e. not benchmarks)? If so I will be impressed. Glancing over the code, it looks pretty short, and I can imagine benchmarks will run, but not real programs. https://github.com/PythonJS/PythonJS/blob/master/pythonjs/pythonjs.py https://github.com/PythonJS/PythonJS/blob/master/pythonjs/py... It's true that most programs don't use all the dynamism of Python, but they probably depend on something that does (e.g. Django). Python is more dynamic than JavaScript, in that it has __getattr__, __setattr__, __getitem__, etc. If not, it's not fair to compare it to PyPy... PyPy actually runs arbitrary Python programs.

belandrew 12y ago
> Python is more dynamic than JavaScript, in that it has __getattr__, __setattr__, __getitem__, etc. No, it's not. You can do equivalents to all of those in Javascript. Javascript objects are all mutable with a few exceptions. They are just maps of properties, very similar to Python's. Properties can be added or changed at runtime. For example, setattr(obj, item, value) in python is basically just obj[item] = value in js.
- craigyk 12y ago
  I think he meant that you can overload operators in python and not javascript... but yeah I agree with you. At the end of the day javascript is still just as, or more, dynamic than python.
- pygy_ 12y ago
  __getattr__ and friends allow to customize the getters and setters. JavaScript is in the process of getting similar capabilities with Harmony proxies, but the spec has yet to be finalized: http://wiki.ecmascript.org/doku.php?id=harmony:direct_proxies http://wiki.ecmascript.org/doku.php?id=harmony:direct_proxie...
  - jonpacker 12y ago
    I'm slightly confused by your wording but I think the functionality you're referring to is already available via Object.defineProperty's "get" and "set" options: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
    - pygy_ 12y ago
      Object.defineProperty allows to overload get/set for a single key at a time. Harmony proxies catch everything, and really overload the getter/setter mechanism.
- bcj 12y ago
  My JS knowledge isn't great. In python, I can do operator overloading such that `obj[item] = value` does something completely different than assignment. Is that possible with JavaScript?
  - jonpacker 12y ago
    You can set a custom getters and setters, but I wouldn't call it operator overloading. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe... So... > var x = {} > Object.defineProperty(x, 'value', { get: function() { return 1 }, set: function() { console.log('set') } }) > x.value 1 > x.value = 2 set > x.value 1
- spankalee 12y ago
  No, JavaScript does not have Python's __getattr__, and obj[name] is not a substitute for it. obj[name] works if you have already either assigned a value for that name, it exists in the prototype chain, or you have defined a getter via Object.defineProperty(). It's truly no different than obj.name[1] - `name` has to already exist in some form. Python's __getattr__ [2] takes the attribute name as an argument, so it can be used to implement property access for any name, even those not known ahead of time. Ruby has something similar with method_missing, and even more with define_method and instance_eval. Dart has noSuchMethod. These are possible to implement in compile-to-JS language, but tricky to make fast. Dart's static analysis looks for all names that could be called on objects with a noSuchMethod, tries to figure out the most specific class it can add them to, then adds stubs to the JS prototypes to redirect to noSuchMethod(). A compile-to-JS Ruby could implement define_method easily enough, but method_missing is would be impossible to do the way Dart does it due to the open classes: you could dynamically add method_missing and not have the stubs available. If you want full Ruby semantics you have to abstract away method calls, which will be slow. I'm guessing the same problem exists for Python, so I wonder the same thing as the grandparent post: did they implement __getattr__ fully? [1] With the small difference in the names that are allowed. [2] https://docs.python.org/3/reference/datamodel.html#object.__getattr__ https://docs.python.org/3/reference/datamodel.html#object.__...
  - bretthartshorn 12y ago
    PythonJS implements __getattr__. See these regression tests: https://github.com/PythonJS/PythonJS/blob/master/regtests/class/__getattr__.py https://github.com/PythonJS/PythonJS/blob/master/regtests/cl... https://github.com/PythonJS/PythonJS/blob/master/regtests/class/mi__getattr__.py https://github.com/PythonJS/PythonJS/blob/master/regtests/cl... __getattr__ and __getattribute__ are implemented in the special __get__ function defined in: https://github.com/PythonJS/PythonJS/blob/master/pythonjs/runtime/pythonpythonjs.py https://github.com/PythonJS/PythonJS/blob/master/pythonjs/ru...
euank 12y ago
Javascript (6) has those in the form of Proxies [0]... Coming soon! I think that they cover the set of features you indicate anyways. However, you can already hack them in and there are multiple js projects that let you compile ES6 down to ES5, proxies included. As other commenters noted, python is not "more dynamic" than javascript. You can easily transform python code that does unusual metaprogramming stuff to javascript code that does similar metaprogramming stuff but looks significantly different; basically all languages that support runtime-eval will let you imitate all other metaprogramming features in a somewhat verbose fashion. [0]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
- chriswarbo 12y ago
  > However, you can already hack them in and there are multiple js projects that let you compile ES6 down to ES5, proxies included. Of course, but will it still be as fast? For example we can trivially turn a Python expression "a + b" into a Javascript expression "a + b" to get a great speed benefit. It may even give correct results in benchmarks, but in general it breaks the semantics and therefore any frameworks which rely on it. FYI in Python "a + b" is equivalent to "a.__add__(b)", and hence the correct Javascript would look more like "a.__add__(b)", but this requires a property lookup and a function call so a lot of the speed gains may be lost (although some benefits may be regained by JITting). Considering that the parent pointed out how small this project's codebase is, it does give legitimate concern about how many rules there are for mapping Python's semantics to Javascript's. For example, the ShedSkin project has been around for years and gets very impressive benchmark results since it compiles Python to C++; however, it tries to map Python classes directly to C++ classes, which breaks the semantics immensely.
  - lclarkmichalek 12y ago
    It's even more complicated than a.__add__(b), due to __radd__: https://www.inkling.com/read/learning-python-mark-lutz-4th/chapter-29/right-side-and-in-place https://www.inkling.com/read/learning-python-mark-lutz-4th/c...
  - 12y ago
bretthartshorn 12y ago
pythonjs.py is not the main part of the translator. PythonJS translates in two steps, most of the translation happens in the first stage, in python_to_pythonjs.py https://github.com/PythonJS/PythonJS/blob/master/pythonjs/python_to_pythonjs.py https://github.com/PythonJS/PythonJS/blob/master/pythonjs/py...

JeremyBanks 12y ago

I also wrote an interpreter, and it's 500x faster than CPython or PyPy. (As it happens, my interpreter can only run a single fixed program, but I'm not worried: most people won't read past the headline when I announce it.)

maaaats 12y ago
Did you have a point?
coldtea 12y ago
>I also wrote an interpreter, and it's 500x faster than CPython or PyPy That's great! Even if your new interpreter doesn't run all the code that's out there it can serve as a base for further work, it's a nice proof of concept and it's just plain cool hacking. It certainly beats all those people merely posting snarky comments on project announcements. >(As it happens, my interpreter can only run a single fixed program, but I'm not worried: most people won't read past the headline when I announce it.) With sarcasm off now, yeah? They worked on something and they are enthusiastic about the results they get. Perhaps they want to oversell them, in a headline. So what? If people "won't read past the headline" then they also won't be using this PythonJS. So no harm done to them. At worst, you'll be lured to read an interesting article. And if you have any understanding of compilers/interpreters at all, you'll know before the end of it who real-world-usable it would be or not.
- zobzu 12y ago
  This kind of thinking generally hurts more than it does good. Large amounts of people will register it in their memory as CPython bad, PythonJS, or really, anything else good. Don't know why, don't know why it's FUD, etc. Next time when they get a choice, they'll bash CPython. Not figuring why everyone uses CPython probably. And you're encouraging that. Probably just thinking it puts you on a higher pedestal or something of the sort. I think its pretty shitty.
  - lucian1900 12y ago
    Well, CPython is embarrassingly slow. The damaging thing is claiming things like PythonJS are implementations of Python, when they merely share syntax and some semantics. They might be fast, but that's not very relevant. Runtimes like PyPy is where we should be looking, since they implement the full Python language and are fast.

WizKid 12y ago

According to the footnote he tested with pypy 1.9. There was just a post here a day or two ago that pypy 2.3.1 was release. Seems like one should at least use the latest version when testing. Pypy 1.9 was release 2 years ago.

srean 12y ago
Yes, but am quite happy and impressed to see how well Pypy is holding up. Something that I have learned about reading benchmarks is to pay attention to who is coming consistently second. Usually that is the most informative part of a benchmark.

vomitcuddle 12y ago

If this project gains more traction, maybe it will get more people interested in Dart. (which is essentially javascript with a standard library reimagined for the things people are using javascript for today: async APIs, stream processing, mapreduce, webapps, etc.)

deleted 12y ago
[deleted]
shadowmint 12y ago
Nothing wrong with Dart (other than lack luster adoption) but I'm not sure a surge in interest of people using it as a dropin backend for compile-to-javasvript targets is really going to drive the sort of developer adoption you'd really be looking for.

rch 12y ago

This just translates Python syntax into JavaScript, assuming a direct translation is possible. Neat, but a more compelling post would compare with CoffeeScript and check build times, high-level syntax, and features like generators, list comprehensions, itertools, functools, and so on. Edit: why the downvote? Am I incorrect about something? If so, I'm genuinely curious to know what I'm overlooking here. Edit 2: I went over to the github page and it is in fact a 'transpiler', though it can run self-hosted in node, and the features list includes both list comprehensions and yield (i.e. generator functions). It looks like the itertools and functools libraries aren't supported yet, but doing so really wouldn't be too difficult. CoffeeScript is a direct output option too.

Pacabel 12y ago
Don't worry about the downvotes. Things have gotten pretty bad around here lately, especially after the whole "downvote if you disagree" policy was encouraged. A lot of totally correct and perfectly valid commentary ends up getting downvoted these days, often with no attempt made to explain why. It's particularly likely to happen when members of the Mozilla, JavaScript or Rust communities are involved. They're particularly sensitive to anything that might contradict their beliefs, and apparently they're particularly eager to downvote, for whatever reason. These days, many of us have started to read all of the downvoted comments. Aside from occasional spam, they're often among the most insightful comments in any given thread.
- dbaupp 12y ago
  > often with no attempt made to explain why. It's particularly likely to happen when members of the Mozilla, JavaScript or Rust communities are involved Your repetitive comments about Rust's instability almost always receive a lot of feedback about why they are incorrect and/or invalid.
  - Pacabel 12y ago
    The Rust mis-votings are quite absurd. In no way can Rust be considered "stable". The most recent version is 0.10 (that is, it's still very pre-1.0), it's undergoing significant breaking changes on an ongoing basis, and even its home page warns that "Rust is a work-in-progress and may do anything it likes up to and including eating your laundry." Anyone who points out that Rust is just not stable yet is absolutely correct. Anyone who points out that it's looking unlikely that it will be stable before the promised end-of-2014 deadline for 1.0 is also correct. It doesn't matter who points out these facts, or how many times they do so. The facts are still facts, and whoever expresses them is totally correct. My suspicion is that the inappropriate downvoting is just immaturity on the part of the Rust developers. I realize that it can hurt to face valid criticism of one's work, but an important part of being a professional adult is to consider such criticism rationally, and to learn how to improve based upon it. Engaging in censorship of facts, however, completely contradicts with self-improvement. It renders the voting system useless when it's incorrectly used to censor others, due to a lack of emotional control on the part of the person misusing the system. It's one thing to downvote blatant commercial spam that has no inherent value. It's harmful to downvote perfectly legitimate commentary that you may just happen to disagree with, however.

chuckup 12y ago

The other interesting and recent "Python in the browser" project is RapydScript - https://github.com/atsepkov/RapydScript https://github.com/atsepkov/RapydScript Unlike PythonJS, it does not have the goal of being 100% Python compatible, but instead takes the CoffeeScript approach. So, like Coffeescript, you get (mostly) clean Javascript output, no huge library dependency, runs nearly as fast as Javascript, etc. Check out the "ants" demo - http://salvatore.pythonanywhere.com/RapydBox/default/editor http://salvatore.pythonanywhere.com/RapydBox/default/editor I've been playing around with both PythonJS and Rapydscript, and I like both. Different goals. PythonJS can output to Lua, too - so there's the whole Python in LuaJIT angle which could be very interesting as it matures.

amirouche 12y ago
Still, it's written in JavaScript. Not aiming full compatibility is not only humility. They can't do it.

zorbo 12y ago

Ah yes, the old X is faster than Y pointless nonsense. Let's ask the basic questions that always come to mind: - Does X do all or at least most that Y does? - Are the benchmarks sane? I.e. not the pointless arithmetic fibonacci that nobody really uses, but the useful stuff such as regexps etc.

spullara 12y ago

Near as I can tell, because CPythong is so tied to native code at every turn, none of the other VMs have any real chance of success without bridging to them.

VeejayRampay 12y ago
Also a big Ruby problem.
lucian1900 12y ago
cffi has been getting more popular lately, though, and it works on both CPython and PyPy. Hopefully this will slowly fix itself.
Shish2k 12y ago
Nice to see I'm not the only one who has a habit of accidentally adding a "g" on the end of "python". Still no idea why that happens though...

pfraze 12y ago

Python in the browser would be pretty fun. Congrats on the speed improvements.

anilshanbhag 12y ago

PyPy uses JIT to generate optimized code during runtime. As many comments noted, PythonJS may not support all Python features but still don't understand why PyPy performing worse than PythonJS.

amirouche 12y ago
You know JIT? I mean does it scale to run the JIT in the browser? I will say maybe. All people that do compiler stuff I asked the question think that it's not.
lucian1900 12y ago
Because PythonJS is not an implementation of Python, it merely looks like Python. It's easy to make a significantly simpler language faster.

zzleeper 12y ago

Nitpick: vertical text is really hard to read, sp if the image is compressed like that. Next time please use some bars instead of columns! Asides from that, this looks quite promising!

bayesianhorse 12y ago

PythonJS might win importance if there was a framework to build webapps with it. Otherwise it's only a curiosity...

millstone 12y ago

Python has bignums by default. I was curious how PythonJS implemented bignums, so I tried it, and the answer is: it doesn't. It just uses ordinary JavaScript doubles. This is a critical difference that ought to be called out, especially in the "add" micro-benchmark, which is measuring two very different things in the two implementations.

bretthartshorn 12y ago
PythonJS has support for 64bit integers using the Long.js library. You just need to type your variable as "long". Numbers larger than 64bits could also be supported with another library and simple modifications to the translator. http://pythonjs.blogspot.com/2014/06/64bit-integer-long-type.html http://pythonjs.blogspot.com/2014/06/64bit-integer-long-type...

coherentpony 12y ago

It'd be interesting to see a comparison with CPython with the 'numpy' backend using a vectorised code.

bretthartshorn 12y ago
Here is a new benchmark testing PythonJS using SIMD vectorized code in the DartVM vs CPython with NumPy. http://pythonjs.blogspot.com/2014/06/pythonjs-simd-vectors.html http://pythonjs.blogspot.com/2014/06/pythonjs-simd-vectors.h...

pandler 12y ago

I'd be interested to see how it stacks up against other python-to-js converters in terms of both speed and supported python features.

SnowLprd 12y ago

The comparisons to PyPy would be much more meaningful if they weren't based on a version of PyPy that's over two years old: PyPy 1.9 was released in 2012.

amirouche 12y ago
You mean 1.9 is not the last stable PyPy?
bretthartshorn 12y ago
I've posted updated benchmarks with the latest PyPy 2.3.1 http://pythonjs.blogspot.com/2014/06/pythonjs-faster-than-cpython-part2.html http://pythonjs.blogspot.com/2014/06/pythonjs-faster-than-cp...