Okay, here’s my dilemma. It looks like this thread wants to devise a new
syntax for lambda, using e.g. (x, y) -> x+y, or the same with =>. That’s
great, but doesn’t open new vistas.
OTOH, for people using type annotations, a much more pressing issue is an
alternative for typing.Callable that is more readable, and supports extra
features that Callable doesn’t, like keyword args, varargs, and pos-only.
If you can do both with the same arrow, great, but if the arrows must
differ (for some technical reason, e.g. types in cast()), I want -> for
Callable, and you can have => for lambda.
—Guido
On Mon, Feb 15, 2021 at 02:51 Steven D'Aprano <st...@pearwood.info> wrote:
> On Mon, Feb 15, 2021 at 02:12:03AM +1100, Chris Angelico wrote:
> > On Sun, Feb 14, 2021 at 8:42 PM Steven D'Aprano <st...@pearwood.info>
> wrote:
> > > We should not choose the more confusing, error-prone solution out of
> > > fear of being different. Python is already different from Javascript in
> > > every regard:
> > >
> >
> > Is it really?
>
> Well, they're both Turing Complete, so I guess not different in *every*
> regard :-)
>
> By the way, I'm not judging the differences.
>
>
> > > - the basic execution model is different;
> > Don't know what you mean here, but I thought they were the same.
>
> Python has a purely dynamic execution model; Javascript has a hybrid
> two-pass model that combines elements of static and dynamic execution,
> and which allows code like this to run:
>
> print(f(3));
>
> function f(a) {
> return a*2;
> }
>
>
> (not in an interactive REPL of course).
>
> Although both Python and Javascript have dynamic typing, Python's
> type model is stronger (i.e. stricter) than Javascript's.
>
> 1 + '2' # an error in Python, 12 in Javascript.
>
> In Python, every thing is an object; in Javascript, some things are
> objects, and some things are primitive values.
>
>
> > > - the object model is different;
> > Same object model.
>
> Absolutely not. Javascript is based on the prototype object model, and
> Python is based on the class object model.
>
>
> https://developer.mozilla.org/en-US/docs/Web/JavaScript/Inheritance_and_the_prototype_chain
>
>
> > > - the numeric model is different;
> > Python has more data types, but that's not as fundamental a difference
> > as you might think
>
> Python has a numeric tower; Javascript has a single floating point type.
> It's hard to build a tower with a single brick :-)
>
>
> > > -the truthy/falsey model is different;
> > There are different rules about WHAT is truthy/falsy, but, again, the
> > differences aren't fundamental
>
> The differences are precisely my point.
>
>
> > > - the syntax is different;
> > > - the list of keywords is different;
> > > - the standard library is different;
> > > - the list of operators is different;
> > Well, of course. If these four were the same, they'd be the same
> > language. These four differ between Py2 and Py3 too.
>
> Yes, the fact that they are different languages is my point.
>
>
> > > - even basic equality is different;
> > Yes, although that's more historic than anything else - most people
> > use "===" which has mostly the same semantics as Python's equality
>
> "Mostly the same", apart from being completely different :-(
>
> Javascript's === tests for "same type and equal" for primitive values,
> and is equivalent to Python's `is` for objects. It cannot be overloaded.
>
>
> > > - the culture of the community is different.
> > TBH neither community has a single culture.
>
> Of course neither group of people is a monoculture of identical
> clones. That would be the Haskell community *wink*
>
> But in general, the JS/Node.js community embraces practices which are
> rejected by the Python community, such as the use of micro-packages.
> Remember left-pad?
>
> This four-line package got nearly fifty million downloads last week:
>
> https://www.npmjs.com/package/isarray
>
> That's about 78 times per second.
>
> If I published that on PyPI, I would be amazed if I got 78 downloads in
> a year.
>
>
> --
> Steve
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--
--Guido (mobile)
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