Mailman 3 - Python-ideas

Undefined type
by Dom Grigonis 13 Jun '23

13 Jun '23

This has been bugging me for a long time. It seems that python doesn’t have a convention for “Undefined” type. When I started using python I naturally used None for it (as advised). However, the more I work with python, the more I find that None is a meaningful type. And it is a type that is convenient to use in a lot of cases, where it is not actually “None”. One big example is: numpy: array[None, :] Another is simple cascading of defaults. E.g. ```python class A: def __init__(self, default=’string'): self.default = default def method(self, default=None): default = default if default is not None else self.default dct[‘key’] = other_dict.get(‘key’, default) return to_json(dct) ``` None has a logic in `some_func`, which is important. Now if I want to enforce None passed to to_json I have no way to do it. I know there are many workarounds for this, but there is no `consistent` way of doing this. I have been using Ellipsis in the past, but it doesn’t feel right, because it also has a meaning and I might need to use those functions with e.g. numpy in he future and will have to change it. Now, I came back to this issue again and my latest solution is to just define: UNDEFINED = object() in library constants.py Then code above is very clear and I think this is a good and sustainable solution. I know, that in a way ’None’ is already this, but it is generally used in 2 ways: 1. A variable/argument is undefined in python space 2. Global indication, that a value is undefined (e.g. equivalence of null in json) What I am proposing is to have 1 more constant in python ‘Undefined’, which will indicate ‘Undefined’ in python space and leave None to be used in more general sense. I also found this article while looking for solution just now: https://levelup.gitconnected.com/python-why-none-is-not-nothing-bb3de55dd471 It seems that people who use typing are also running into ambiguities and trying to hack something together. I avoid typing until its 99% mature so can't comment more on this. What are your thoughts? Am I onto something or am I missing something? Anyone else had similar encounters?

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Please update shutil.py copyfileobj to include code mentioned in below issues
by jschwar＠sbcglobal.net 09 Jun '23

09 Jun '23

I opened two issues regarding copyfileobj that were not bugs, but a fix that was involved helped me figure out I needed a new external drive, since it displayed the error number from the copyfileobj function. I'd like a modified version of this code implemented permanently in shutil.py so others could see if they have the same issue as me. Here are the two issues I opened: This is the original issue that has the code I was using that Eryksun posted. https://github.com/python/cpython/issues/96721 Here's the second issue where it happened again. I put the error message in this post, so you can see how it helped me. Also, the code might need to be modified slightly, since it generated an error. https://github.com/python/cpython/issues/102357

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Explicit encapsulation is better than implicit hardcoding?
by Dom Grigonis 09 Jun '23

09 Jun '23

Hey there! I'm curious to know what this group thinks about the implicit design of many Python libraries, both core and open source. What I mean by "implicit design" is when an interface of library is established and initialised at module’s level rather than explicitly encapsulated in classes. Couple of the examples: 1. logging 2. asyncio Both of the libraries (by design) allow only 1 framework per process, which can be limiting. Although it's easier to hack the logging library to obtain an independent hierarchy with separate root node, it's a bit more challenging to obtain a separate asyncio loop. Allowing users to instantiate a fresh instance of framework would be advantageous in various ways: 1. "Explicit is better than implicit" - easier to understand, inherit, and edit. 2. The ability to instantiate multiple framework nodes leads in a modifiable, therefore easier to comprehend workflow. For example, having separate logging and asyncio on a thread would provide for greater design freedom. 3. Code reusability. When I am looking for code (to avoid reinventing the wheel), whenever I find initialisations at the module level it is a signal that the code is not easily reusable, and I continue my search. I'll return to such code as a last option. I think such design is reasonable for “end result” products, that are not at the risk of becoming standard dependencies, but is it a good idea to continue this standard practice for "building block" libraries? It is not a complaint in and of itself (maybe a bit), but rather an attempt to spark a discussion about whether more modular and explicitly contained architecture would help the Python community the most in the long run.

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Keyword argument support for exec/eval?
by Raphael Gaschignard 07 Jun '23

07 Jun '23

I have searched for chatter about this in the past, and realize that churning about on this topic might be a bit of a time waster, but what would be required to make eval and exec be able to take keyword arguments? Explaining exec and eval, and not being able to use kwargs to establish an ordering (especially when the docs talk about defaults) is not great IMO. Has there been discussion in the past on when adding kwarg support for existing functions becomes a thing that patches are accepted for?

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`join` method for the `list` class ... `list.join`
by Samuel Muldoon 07 Jun '23

07 Jun '23

To Whom it May Concern, Python's `str` class has a method named `join` I was wondering if a future release of python could have a `list.join` which behaves in a similar fashion. *result = [99].join([1, 2, 3])print(result)# prints [1, 99, 2, 99, 3]* *Samuel Muldoon* *(720) 653 -2408* *muldoonsamuel(a)gmail.com <muldoonsamuel(a)gmail.com>*

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New Ideas for Python - Oregon State University Open Source Software Course
by Woodlock, Eric 06 Jun '23

06 Jun '23

Hello, I am a Computer Science student at Oregon State University and would like to submit some ideas/feature requests for the Python programming language as part of a project for an Open Source Software course I am taking. I am a subscriber to the Python-Ideas mailing list. 1) The first idea/feature request I have is to add multi-line commenting to the Python programming language. Many other programming languages have this functionality and I believe adding multi-line commenting to Python will improve its efficiency for developers. 2) The second idea/feature request I have is to add capability to optimize for database access and usage. The reason for creating capability to optimize for database access and usage is the fact that Python lacks a high-quality and convenient interface for dealing with databases relative to other languages. Databases are utilized in so many applications today and implementing such functionality for Python would make a big difference in terms of strengthening the language. 3) The third idea/feature request I have is to add functionality for mobile application development to the Python programming language. The rationale for implementing additional capability for mobile application development is to further Python’s usage in that area. Python, while used in a variety of applications, truly lacks high quality mobile development functionality and adding it would improve the language greatly. I look forward to any feedback you may have. Thank you, Eric

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Add a .whitespace property to module unicodedata
by Antonio Carlos Jorge Patricio 03 Jun '23

03 Jun '23

I suggest including a simple str variable in unicodedata module to mirror string.whitespace, so it would contain all characters defined in CPython function [_PyUnicode_IsWhitespace()](https://github.com/python/cpython/blob/main/Obje… so that: # existent string.whitespace = ' \t\n\r\x0b\x0c' # proposed unicodedata.whitespace = ' \t\n\x0b\x0c\r\x1c\x1d\x1e\x1f\x85\xa0\u1680\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u2028\u2029\u202f\u205f\u3000'

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extend method of the list class could return a reference to the list so that we can chain method calls
by Samuel Muldoon 02 Jun '23

02 Jun '23

*Currently, list.extend does not allow method chaining.* *parameters = [ "zero or more", "zero or more".upper(), "zero or more".lower(), "Zero or More"* *].extend(["(0, +inf)", "[0; +in**f]"])* *parameters.extend(["{0, \u221E}"]).append("(0 inf)")* *Samuel Muldoon* *(720) 653 -2408* *muldoonsamuel(a)gmail.com <muldoonsamuel(a)gmail.com>*

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Add a .whitespace property to module unicodedata
by Antonio Carlos Jorge Patricio 01 Jun '23

01 Jun '23

I suggest including a simple str variable in unicodedata module to mirror string.whitespace, so it would contain all characters defined in CPython function [_PyUnicode_IsWhitespace()](https://github.com/python/cpython/blob/main/Obje… so that: # existent string.whitespace = ' \t\n\r\x0b\x0c' # proposed unicodedata.whitespace = ' \t\n\x0b\x0c\r\x1c\x1d\x1e\x1f\x85\xa0\u1680\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u2028\u2029\u202f\u205f\u3000'

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Virtual packages
by Soni L. 21 May '23

21 May '23

Python allows setting __path__ to turn a module into a package. However, it's allegedly only defined for __init__.py? Proposal: A virtual package is a non-__init__.py whose first line of code, after comments and future imports, assigns to __path__. This would allow -m virtualpackage to call virtualpackage.__main__, wherever that is. Instead of running virtualpackage.py as __main__.

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