[Python-ideas] Re: Optional keyword arguments

Greg Ewing writes: > To my mind, the signature consists of information that a > static type checker would need to verify that a call is valid. > That does not include default values of arguments. That's a parsimonious and reasonable definition, and the one historically used by Emacs Lisp. But

[Python-ideas] Re: Python __main__ function

Also, I routinely write scripts that have no `if __name__ == '__main__'` line at all, they just run - no-one should ever import them, so it makes no difference. And I exit (in multiple places) using `raise SystemExit("reason")`. My point being that yes, there are *lots* of ways of writing Python s

[Python-ideas] Re: An HTTP API to list versions of Python

Since cutting releases is done by the release manager, producing such meta would have to be part of his or her role. The tools RMs use are here: https://github.com/python/release-tools/ The PEP describing the process: https://www.python.org/dev/peps/pep-0101/ Looking through the release.py scrip

[Python-ideas] Expose PyFloat_AsDouble to Python

Here's the short version: * "Convert float-like object to a float" is a useful operation * For a C extension, there's an obvious way to spell that operation: use `PyFloat_AsDouble` * In pure Python, there's no Obvious Way To Do It * Proposal: expose the equivalent of `PyFloat_FromDouble(PyFloat_

[Python-ideas] Re: Expose PyFloat_AsDouble to Python

29.05.20 12:48, Mark Dickinson пише: 2. Call the object's `__float__` method. But this is fraught with peril, too: for a proper equivalent, you need to be careful to look up `__float__` on the type, not the object itself. And then a new version of Python changes `PyFloat_AsDouble` to also acce

[Python-ideas] Re: Optional keyword arguments

On Fri, May 29, 2020 at 12:36:20PM +1200, Greg Ewing wrote: > On 29/05/20 12:17 am, Richard Damon wrote: > >But default values for arguments are really part of the responsibility > >for the caller, not the called function. The classic implementation > >would be that the caller passes all of the exp

[Python-ideas] Re: Optional keyword arguments

On Thu, May 28, 2020 at 12:11:38PM +0200, Alex Hall wrote: > Consider this code: > > ``` > x = 1 > > def foo(): > print(x) > x = 2 > > foo() > ``` > > Here `print(x)` doesn't print '1', it gives `UnboundLocalError: local > variable 'x' referenced before assignment`. It knows that `x` i

[Python-ideas] Re: Optional keyword arguments

On Thu, May 28, 2020 at 08:04:07PM +1000, Chris Angelico wrote: > On Thu, May 28, 2020 at 8:01 PM Steven D'Aprano wrote: > > > > On Wed, May 27, 2020 at 05:03:09AM +1000, Chris Angelico wrote: > > > > > def foo(): > > > if False: x = 0 > > > # what is x now? > > > > > > There is no *value*

[Python-ideas] Re: Optional keyword arguments

On Fri, May 29, 2020 at 10:51 PM Steven D'Aprano wrote: > > On Thu, May 28, 2020 at 08:04:07PM +1000, Chris Angelico wrote: > > If it's a > > language feature, then the name 'x' must be in the state of "local > > variable without a value". > > Oh ho, I see what you are doing now :-) > > I'm going

[Python-ideas] Re: Expose PyFloat_AsDouble to Python

On Fri, 29 May 2020 09:48:53 - "Mark Dickinson" wrote: > > I have a proof-of-concept PR [1] that exposes this in the `operator` module > as `operator.as_float`. See also the discussion on the tracker [2]. `operator.as_float` sounds good to me. There's the `operator.index` precedent. Regar

[Python-ideas] Re: Python GIL Thoughts

Yesterday RustPython team finished threading without GIL: https://github.com/RustPython/RustPython/issues/1831 ___ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.o

[Python-ideas] datetime.time input restrictions

I was wondering why have restrictions on the datetime.time constructor arguments? For example, why can't you enter 1.5 minutes or 90 seconds to create a datetime object with 1 minute and 30 seconds? >>> datetime.time(minute=1.5) Traceback (most recent call last): File "", line 1, in TypeError:

[Python-ideas] Re: Expose PyFloat_AsDouble to Python

29.05.20 14:22, Serhiy Storchaka пише: I prefer it to be an alternative float constructor. We can also add the corresponding constructor for complex, and add constructors which accept only str, bytes or bytes-like object (i.e. parse a text representation of the number). See also previous discus

[Python-ideas] Re: Optional keyword arguments

On 29.05.20 15:09, Chris Angelico wrote: On Fri, May 29, 2020 at 10:51 PM Steven D'Aprano wrote: On Thu, May 28, 2020 at 08:04:07PM +1000, Chris Angelico wrote: If it's a language feature, then the name 'x' must be in the state of "local variable without a value". Oh ho, I see what you are d

[Python-ideas] Re: Python __main__ function

I agree with Paul's sentiment. We do not need to bless just one way of writing scripts. Code review or organization style guides, sure. But not at language level. I also write scripts with no explicit __main__. But I rarely name them as .py. In the style of Unix commands, they have no extension, b

[Python-ideas] Re: datetime.time input restrictions

On Sat, May 30, 2020 at 12:57 AM Ben Axelrod wrote: > > I was wondering why have restrictions on the datetime.time constructor > arguments? For example, why can't you enter 1.5 minutes or 90 seconds to > create a datetime object with 1 minute and 30 seconds? > > >>> datetime.time(minute=1.5) >

[Python-ideas] Re: Python GIL Thoughts

On 2020-05-29 15:19, redrad...@gmail.com wrote: Yesterday RustPython team finished threading without GIL: https://github.com/RustPython/RustPython/issues/1831 That first example is Python 2... ___ Python-ideas mailing list -- python-ideas@python.

[Python-ideas] Re: Optional keyword arguments

On Fri, May 29, 2020 at 2:18 PM Steven D'Aprano wrote: > On Thu, May 28, 2020 at 12:11:38PM +0200, Alex Hall wrote: > > > Consider this code: > > > > ``` > > x = 1 > > > > def foo(): > > print(x) > > x = 2 > > > > foo() > > ``` > > > > Here `print(x)` doesn't print '1', it gives `UnboundL

[Python-ideas] Re: Optional keyword arguments

On Fri, May 29, 2020 at 3:19 AM Stephen J. Turnbull < turnbull.stephen...@u.tsukuba.ac.jp> wrote: > # Just too ugly for me! > def foo(x=lambda: random.randint(0,9)): > > x = x() > # ... > I think this is a perfect example of where my desired "delayed" (or "deferred") const

[Python-ideas] Re: Optional keyword arguments

On Fri, May 29, 2020 at 7:05 PM David Mertz wrote: > On Fri, May 29, 2020 at 3:19 AM Stephen J. Turnbull < > turnbull.stephen...@u.tsukuba.ac.jp> wrote: > >> # Just too ugly for me! >> def foo(x=lambda: random.randint(0,9)): >> >> x = x() >> # ... >> > > I think this is a

[Python-ideas] Re: Optional keyword arguments

> > Where do we draw the line? How much of the behaviour of the > > function do we want to move into the header? > > Well obviously we don't draw the line until we've fallen down the > slippery slope and the entire body of the function is part of the > header! > Sure, what's the problem? :-) def

[Python-ideas] Re: Optional keyword arguments

On Fri, May 29, 2020 at 1:12 PM Alex Hall wrote: > def foo(a=17, b=42,, x=delayed randint(0,9), y=delayed randrange(1,100)): > >> if something: >> # The simple case is realizing a direct delayed >> val = concretize x >> elif something_else: >> # This line creates a

[Python-ideas] Re: Optional keyword arguments

On 29/05/2020 18:02, David Mertz wrote: I think this is a perfect example of where my desired "delayed" (or "deferred") construct would be great. There are lots of behaviors that I have not thought through, and do not specify here. But for example: def foo(a=17, b=42,, x=delayed randint(0,9),

[Python-ideas] Re: Python GIL Thoughts

Hello, On Fri, 29 May 2020 14:19:40 - redrad...@gmail.com wrote: > Yesterday RustPython team finished threading without GIL: > https://github.com/RustPython/RustPython/issues/1831 So what? As was pointed out, there're bunch of Python implementations which don't use GIL. And it's very eas

[Python-ideas] Delayed computation

On Fri, May 29, 2020 at 1:56 PM Rhodri James wrote: > Presumably "delayed" is something that would be automatically applied to > the actual parameter given, otherwise your call graphs might or might > not actually be call graphs depending on how the function was called. > What happens if I call "

[Python-ideas] Re: Python GIL Thoughts

> -Original Message- > From: Paul Sokolovsky > Sent: Friday, May 29, 2020 2:26 PM > To: redrad...@gmail.com > Cc: python-ideas@python.org > Subject: [Python-ideas] Re: Python GIL Thoughts > > Hello, > > On Fri, 29 May 2020 14:19:40 - > redrad...@gmail.com wrote: > > > Yesterday R

[Python-ideas] Re: Python GIL Thoughts

Hello, On Fri, 29 May 2020 14:44:40 -0400 wrote: [] > These are things that a runtime implementer has to decide on. These > are also thing that a runtime use gets to complain about. "Don't > share data amongst threads" is not advice to the cpython user to get > truly parallel thread execution

[Python-ideas] Re: Python GIL Thoughts

I've just share information, relax ;) And also it seems like they have very low overhead with atomic variables Arc ___ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.

[Python-ideas] Re: Delayed computation

On 29.05.20 20:38, David Mertz wrote: On Fri, May 29, 2020 at 1:56 PM Rhodri James mailto:rho...@kynesim.co.uk>> wrote: Presumably "delayed" is something that would be automatically applied to the actual parameter given, otherwise your call graphs might or might not actually be

[Python-ideas] Advanced Debugger Support C-API is incomplete?

I want to implement my own version of _PyThread_CurrentFrames() , but it seems like it's not possible using public C-API. The comment

[Python-ideas] Re: Delayed computation

On Fri, May 29, 2020 at 5:06 PM Dominik Vilsmeier wrote: > I'm still struggling to imagine a real use case which can't already be > solved by generators. Usually the purpose of such computation graphs is to > execute on some specialized hardware or because you want to backtrack > through the grap

[Python-ideas] Re: Optional keyword arguments

On Fri, May 29, 2020 at 04:52:38PM +0200, Dominik Vilsmeier wrote: > Indeed locals are special, but why was it designed this way? Why not > resolve such an unbound local name in the enclosing scopes? Probably for speed. When I first learned about the LGB rule (so long ago there wasn't even an E

[Python-ideas] Re: Optional keyword arguments

On Fri, May 29, 2020 at 06:03:30PM +0200, Alex Hall wrote: > > I never said that Python's scoping rules were implementation details. > > > > I said that the storage mechanism of *how* local variables are stored, > > and hence whether or not writes to `locals()` are reflected in the > > local varia

[Python-ideas] Re: Optional keyword arguments

On 29/05/20 11:49 pm, Steven D'Aprano wrote: Where else would you put the parameter defaults, if not in the parameter list? In some part of the function that's not the parameter list. :-) There are many ways it could be done. I've suggested one already (a special assignment statement). Anothe

[Python-ideas] Re: Optional keyword arguments

On 30/05/20 12:11 am, Steven D'Aprano wrote: I said that the storage mechanism of *how* local variables are stored, and hence whether or not writes to `locals()` are reflected in the local variables, is an implementation detail. That's true, but just to be clear, my ?= idea doesn't rely on that

[Python-ideas] Re: Optional keyword arguments

Attempting to bring things back on topic to function parameters with late binding. On Fri, May 29, 2020 at 06:03:30PM +0200, Alex Hall wrote: > Chris was just saying that a statement like `x ?= y` meaning 'assign the > value of y to the local variable x if x is currently unbound' already fits >

[Python-ideas] Re: Optional keyword arguments

On 30/05/20 2:52 am, Dominik Vilsmeier wrote: Indeed locals are special, but why was it designed this way? Why not resolve such an unbound local name in the enclosing scopes? From experience with other languages I can attest that "sometimes local, sometimes global depending on what gets execute