Mailman 3 October 2019 - Python-ideas

Simple feature for argparse.py
by brent bejot 10 Oct '19

10 Oct '19

Hello all, Aspiring contributor here. I am not at all certain that this is the right place to discuss this. Do refer me to a better location if I'm out of place. I would like to add a simple feature to the argparse library. I frequently find myself writing small utilities, stylistically similar to unix's "rm" whose main parameter(s) get bundled into a list and it doesn't matter if flags are sprinkled throughout. e.g. "rm foo.txt -f bar.txt" removes both foo.txt and bar.txt forcefully. Doing this in argparse currently is cumbersome at best (though I would be happy to be proved wrong on that), so I rarely implement it as a feature. Of note, calling parser.add_argument with nargs="..." or nargs="A..." or nargs="*" gets close, but will not allow you to intermix other flags between your list. I have a working modification of argparse.py that I could commit, but I know there's several steps between here and there - I just don't know what those steps are. Any direction would be very much appreciated. Thanks!

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Re: Adding support for adequately tagging AIX (pep425) to support distributed wheels
by Michael Felt 09 Oct '19

09 Oct '19

Among other places, Python ideas was recommended as a place to goto. In the meantime I have been discussing this on pypa/pip (mainly), and also on wheel and packaging. Even submitted PRs. But the PRs are only needed if the tag is inadequate. So, part of my reason for being here is to figure out if I can call the current tag algorithm a bug, or is correcting it a feature? I am trying to approach this the Python way rather than be seen as a bull in a china shop. Thanks for replying! Sent from my iPhone

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adding "port" parameter to urllib.parse.urlunparse
by AMIR MOHAMMADI 09 Oct '19

09 Oct '19

Hi. I'm a newbie and Python ideas was recommended to me as a place to go to. I think this is a good idea that have port parameter in "urlunparse" method. (refer to: https://bugs.python.org/issue38408) One way is to add keyword parameters to urlunparse, like: def urlunparse(components, *, username=None, password=None, hostname=None, port=None): Which would be called like this: site_to_test = urllib.parse.urlunparse((scheme, host, page, '', '', ''), port=9097) Another interface would be have all URL parameters passed in as keyword arguments. so you can't pass in both "components" and any other named parameter. Like this: def urlunparse(components=None, scheme=None, netloc=None, path=None, params=None, query=None, fragment=None, *, username=None, password=None, hostname=None, port=None): And then error if components is set and any of other named parameters are also set. My question is which would we prefer?

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Allow kwargs in __{get|set|del|}item__
by Caleb Donovick 09 Oct '19

09 Oct '19

While there is no restriction on passing dicts to getitem. Doing so tends to be a bit ugly. I have two main use cases in mind for this syntax. The first and perhaps the most obvious, is doing relational queries. ``` where_x_1 = db[x=1] ``` is more beautiful than ``` where_x_1 = db[dict(x=1)] where_x_1 = db[{'x': 1}] # or by abusing slices where_x_1 = db['x':1] # or in the style of Pandas where_x_1 = db[db['x'] == 1] ``` Beyond relational queries my own personal use case is a shorthand for dataclasses / protocols. ``` foo: ProtoRecord[x=int, y=int] = DataRecord[x=int, y=int](0, 1) ``` where `DataRecord[field0=T0, ..., fieldk=Tk]` generates ``` @dataclass class Record: field0: T0 ... fieldk: Tk ``` and `ProtoRecord[field0=T0, ..., fieldk=Tk]` generates a similar protocol. Allowing key value pairs in geitem need not change the interface of getitem. All the key value pairs could be collected as a dict and passed to getitem as the index. Similar to how the all the positional arguments are gather into a single tuple. ``` class Foo: def __getitem__(self, idx): print(idx) f = Foo() f[x=1, y=2] # {'x': 1, 'y': 2} ``` This would make any legacy code using normal dicts as keys (I don't know how prevalent that is) automatically work with the new syntax. There doesn't necessarily need to be support for mixing of tuple based indexing and keyword indexing. i.e. ``` obj[0, x=1] # SyntaxError ``` I don't really know anything about parsers but I think the grammar could be extended without issue with the following rule: ``` subscriptlist: ... | kwargsubscript (',' kwargsubscript )* [','] kwargsubscript: NAME '=' test ``` if `NAME '=' test` would result in ambiguity similar to argument it could be `test '=' test` with a block in ast.c - Caleb Donovick

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Quick notice about an update to the Code of Conduct
by Brett Cannon 03 Oct '19

03 Oct '19

We just wanted to quickly let people know that the PSF Code of Conduct recently got an update: https://pyfound.blogspot.com/2019/09/the-python-software-foundation-has_24.…. Since this list falls under the PSF CoC these changes apply here. In terms of reporting CoC violations, you can continue to report them to python-ideas-owner@ and then Titus and I will have a look. Otherwise you can always report directly to conduct@ (see https://www.python.org/psf/conduct/reporting/ for details).

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