Now it seems Python doesn’t need constant. There are many ways we can achieve constants. Though constants may increase performance. Yet again it can also be the opposite.
________________________________ From: Paul Sokolovsky <pmis...@gmail.com> Sent: Saturday, May 29, 2021 12:44:09 AM To: Shreyan Avigyan <pythonshreya...@gmail.com> Cc: python-ideas@python.org <python-ideas@python.org> Subject: [Python-ideas] Re: Introduce constants in Python (constant name binding) Hello, On Tue, 25 May 2021 11:53:20 -0000 "Shreyan Avigyan" <pythonshreya...@gmail.com> wrote: > I posted my previous idea regarding this on the mailing list. This > idea is a little different. This idea suggests introducing constant > name bindings. This is similar to const pointer in C/C++. Once a name > has been assigned to a data we can change the data (if mutable) but > we cannot change the name to point to a different data. The only way > the data the constant points can get deallocated is if it goes out of > scope, the program exits or the constant is manually `del` by the > user. The proposed syntax is as follows, > > constant x = 10 > constant y = ["List"] > constant z: str = "Hi" The idea of introducing constants on the core language level in Python is well-known topic and was brought up on multiple occasions both on the python-ideas and python-dev mailing lists. A random example: https://www.mail-archive.com/python-dev@python.org/msg110424.html "constants in Python: Starting simple and gradually adding more features, was: Re: Pattern Matching controversy" The matter is actually implementing it in different Python implementations. And some implementations had support for *some kind* of constants for many years (e.g. MicroPython with it's pre-annotation syntax of "FOO = const(1)"), while CPython still has it only on the level of external first-generation annotation module, "typing". As another example, I can give "strict mode" (https://www.mail-archive.com/python-ideas@python.org/msg25403.html) feature of my Python dialect, Pycopy (https://github.com/pfalcon/pycopy), which implements some (but again, not all) aspects of const'ness. E.g.: === print("In import-time") a: const = 1 a: const = 2 def __main__(): print("In run-time") global a a = 3 === Gives: ==== In import-time Warning: strict mode: overriding (monkey-patching) const name 'a' In run-time Traceback (most recent call last): File "strict.py", line 9, in __main__ RuntimeError: strict mode: cannot override const name ==== -- Best regards, Paul mailto:pmis...@gmail.com _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/PHU3YE47SI55JODFG3W53GZIJK6IH4FL/ Code of Conduct: http://python.org/psf/codeofconduct/
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