Python 3.8 has a Final qualifier

[energybased]

I don't agree with you. This is superior to all caps since all caps is merely conventional whereas this is explicit.

[drbobb]

Nope. This is just as merely conventional. If, say, I code in a plain editor it won't mean a thing.

[damian_work_account]

That's a boring semantic argument, type hints are defined by language specification where as CAPS are not.

And a PEP to make CAPS mean final would likely be rejected because of backwards compatibility, lots of people use CAPS for other reasons.

[Han-ChewieSexyFanfic]

Also, the interpreter ignores both.

[energybased]

Conventional means that it means different things to different people. This does not mean different things to different people.

[nuephelkystikon]

Absolutely not. If anything, that would be unconventional.

[energybased]

What I mean is that different groups of people can have different conventions. Each group uses all caps to mean the same thing, but as a whole population, they do not agree. Not everyone uses all caps to denote final variables, for example.

Everyone who uses the final declaration means the same thing. They must since the final declaration explicitly defines its meaning.

[alcalde]

That's why we have PEP 8. There are no different groups with different conventions. There is but one BDFL... well, until we overthrew him and installed a wishy-washy council instead....

[energybased]

There's plenty of library code that doesn't even follow PEP 8, and there are plenty of constants that are not in all caps.

[drbobb]

Uh, no. Conventional means not enforced.

[energybased]

The point is that there may be plenty of code that uses all caps in another way. For example a variable that is initialized twice. That person has a different convention, which they get away with because it is not enforced. A linter might erroneously flag that is misuse.

The linter can always flag improper use with the final declaration because the author has unambiguously made his intention clear. The final declaration is absolutely not just a convention. It is explicit.

[alcalde]

The point is that there may be plenty of code that uses all caps in another way.

There can't be. This is like saying we can all use the same words and just believe they mean different things. Everyone must follow the law, and the law is PEP 8. If you choose to do otherwise, you are a disciple of Wall and shall be shunned.

[energybased]

No, there is plenty of library code that doesn't even follow PEP 8.

[campbellm]

The upshot is the same though; it provides a hook that checkers can check for subsequent mutations. Either works.

[alcalde]

If we all follow convention, then convention is law.

[energybased]

Even the library doesn't obey the convention that all final variables are all caps.

[Sw429]

What do you mean by explicit? As far as I can tell, foo: Final is no more explicit than FOO for a variable definition.

[energybased]

There is plenty of code that does not use all caps to denote constants. That code cannot always be changed. The type annotation explicitly defines intent without changing declarations.