PyPy.js: A fast, compliant Python implementation for the web

Post by e12e » Thu, May 07, 2015, 5:58 AM UTC

bzbarsky wrote: post #112

e12e wrote: post #46

Earlier quoted context omitted.

Seems to be some issues with the interop still, eg: import js >>> "globals" in dir(js) True >>> "console" in dir(js.globals) False >>> js >>> js.globals.console So apparently introspection doesn't quite work with the wrapped js. Also, if you try: "[ i for i in js.globals]" (or equivalently iterate/loop over the globals-object) - the whole repl/tab hangs. Not really an issue for running business logic in the browser,…

The introspection bit is because js.globals is implemented with a fancy __getattr__ but doesn't have a __dir__. In general, dir() is not reliable in the face of custom __getattr__ implementations unless the implementor goes out of the way to make it work.

  Welcome to PyPy.js!
  >>> import js
  >>> "console" in js.globals
  True
  >>> "console" in dir(js.globals)
  False

Post by fijal » Thu, May 07, 2015, 7:47 AM UTC

pcwalton wrote: post #118

fijal wrote: post #84

Earlier quoted context omitted.

No, because it's "AOT" compiled when it's downloaded or executed (since you have one JIT, you can't AOT compile what it produces). So you can think about it as "just" one JIT, but a very inefficient one

> since you have one JIT, you can't AOT compile what it produces I'm not sure what this means, but if you mean that Firefox doesn't cache compiled asm.js code, that's not true. It does [1]. [1]: https://blog.mozilla.org/luke/2014/01/14/asm-js-aot-compilat...

Post by TazeTSchnitzel » Thu, May 07, 2015, 11:14 AM UTC

fijal wrote: post #134

TazeTSchnitzel wrote: post #100

Earlier quoted context omitted.

Not quite. At least Firefox caches compiled asm.js.

You can't cache JITted code (so JIT produced by pypy.js) because it'll be different each time.

Post by alexweber » Thu, May 07, 2015, 6:35 PM UTC

fragmede wrote: post #105

Nitramp wrote: post #103

I think there is no point in trying to emulate different language semantics on top of JavaScript. asm.js is a weird hack that lives in a totally different world than actual browser APIs (e.g. the DOM), and you have to emulate your entire runtime and environment to get anything useful, which means your binary is going to be huge (as in this example, but similar things apply). Emulating better semantics than JS based o…

> That'd be TypeScript. Or CoffeeScript. Or Dart. Or this. In fact, here's a whole big long list of other languages. Most of which don't use the asm.js "weird hack". https://github.com/jashkenas/coffeescript/wiki/List-of-langu...

Post by Tossrock » Fri, May 08, 2015, 12:08 AM UTC

caryhartline wrote: post #120

Tossrock wrote: post #115

Looks like there are some issues to iron out... >>> from datetime import datetime >>> datetime.now() Traceback (most recent call last): File " ", line 1, in File "/lib/pypyjs/lib_pypy/datetime.py", line 1548, in now return cls.fromtimestamp(t, tz) File "/lib/pypyjs/lib_pypy/datetime.py", line 1522, in fromtimestamp result = cls(y, m, d, hh, mm, ss, us, tz) File "/lib/pypyjs/lib_pypy/datetime.py", line 1459, in __new_…

That works now.

  >>> from datetime import datetime
  >>> datetime.now()
  Traceback (most recent call last):
    File "", line 1, in 
    File "/lib/pypyjs/lib_pypy/datetime.py", line 1548, in now
      return cls.fromtimestamp(t, tz)
    File "/lib/pypyjs/lib_pypy/datetime.py", line 1511, in fromtimestamp
      us = _round(frac * 1e6)
    File "/lib/pypyjs/lib_pypy/datetime.py", line 28, in _round
      return int(_math.floor(x + 0.5) if x >= 0.0 else _math.ceil(x - 0.5))
  ValueError: cannot convert float NaN to integer