A Python-to-JavaScript Transpiler with BabelJS and SourceMaps (opens in new tab)

> push this on the python 3 community to make this a standard library

Do you mean "standard" as in "the community's most often used", or as in "included in the standard library"?

A wise man once told me that "the standard library is where libraries go to die."

Too late. Python is screwed. Its still slow and not portable.

Julia is a dynamic language that can compile to fast binary code. Once it can be run in the browser with web assembly, faster and nicer syntax than javascript, why would anyone use python?

At this point, Randall needs to write an XKCD on the notion of referencing "that one XKCD" (whichever one pertains to the given circumstance).

There's an XKCD for just about anything...

This comment perfectly sums up my expectations of modern JS libraries.

I think op forgot /s! :P

At least I hope...

The part about `lambda` is certainly imprecise. You can use the ternary form of `a if b else c` and you can use comprehensions and/or functional style with `map` or `filter` or things from itertools if you want iteration in a `lambda`. Instead of putting statements inside the `lambda`, you should write whatever would be a statement as a helper function, and just refactor the `lambda` so that the sequence of statements you wanted will just be some expression.

I didn't check in Python 2, but in Python 3 anyway, `type()` of a `lambda` is definitely `function` and the `lambda` object has a `__code__` attribute with `co_code` containing the actual bytecode, so it's definitely a function.

For raising errors, once again you can just define a helper that does the raising -- the limitation here is the use of statements, not anything inherent to exceptions. For example:

    In [56]: def r():
       ....:     raise TypeError
       ....: 

    In [57]: f = lambda x: x[0] if isinstance(x, list) else r()

    In [58]: f([1])
    Out[58]: 1

    In [59]: f("hi")
    ---------------------------------------------------------------------------
    TypeError                                 Traceback (most recent call last)
    <ipython-input-59-987cd5963ca4> in <module>()
    ----> 1 f("hi")

    <ipython-input-57-b0e388d24fbc> in <lambda>(x)
    ----> 1 f = lambda x: x[0] if isinstance(x, list) else r()

    <ipython-input-56-a540441a09db> in r()
          1 def r():
    ----> 2     raise TypeError
          3 

    TypeError:

The same idea would work with context managers, etc.

FWIW, having used Python for a long time, I see the limitations on `lambda` as very good things. `lambda` should almost never be used for complex, side-effectful logic, and instead should be used when a short expression needs to be encapsulated and it's easier to do so with an anonymous function than a full function definition, and to a lesser extent sometimes for some tricky metaprogramming use cases, like dynamically binding functions at run time.

I'm sure that high-quality Javascript style probably implicitly uses these same kinds of limitations, even if the language itself doesn't make it mandatory.

It'd be related to inlining a function since size is a common rule there. Some searching turns up this[1] article on crankshaft from three years ago, which lists the restrictions as ">600 source characters including whitespace or 196 AST nodes".

[1] http://jayconrod.com/posts/54/a-tour-of-v8-crankshaft-the-op...

Is this supposed to be able to work for really large apps at some point? Some commenter lamented how it didn't work with django.

awesome, thanks for the info!

>Keyword arguments accumulator has no corresponding feature in the ES6 world, as far as I know....

As a feature no, but Python code using that could be easily transpiled to a function taking a dict with the args...

I'd love to but

a) make failed b) I didn't really want to build something just to see an example running ;-) c) you don't have an issues turned on in Github so I couldn't file a bug.

It would be lovely if you could host the example somewhere and link to it. Or failing that - have a compiled example in the repo so the idle and curious can try it out with jumping through any hoops.