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Been reading up on #Python lately. I know that classes in Python "doesn't support" private values, but could this functionality not be implemented with closures?

Edit: typo
#python
Jonathan Lamothe

Content warning: boring nerd stuff (example code)

Gabriel Pettier

Content warning: boring nerd stuff (example code)

This entry was edited (2 months ago)
Gabriel Pettier
something like this? Sure the class can save the value in a method and return that later, but then i get the same problem, anything can decide to patch this method instead.
Python class patching its own method to return a different result ``` class ClosureClass: def set_val(self, value): self.get_val = lambda: value def get_val(self): return "default value" if __name__ == '__main__': cl = ClosureClass() print(cl.get_val()) cl.set_val("another value") print(cl.get_val()) print(ClosureClass().get_val()) ``` running this code displays ``` default value another value default value ```
Jonathan Lamothe
@Gabriel Pettier That's even cleaner than what I'd conceptualized, yes.
@Gabriel Pettier
Gabriel Pettier
well, it's not very clean, as self modifying code is not a good friend of code that is easy to reason about and maintain, and that will likely confuse type checkers and other tools. And it doesn't solve the problem, since i can totally do cl.get_val = lambda: "test" instead of calling cl.set_val("test").
Jonathan Lamothe
@Gabriel Pettier That's true. It's not what I would consider to be a *good* idea. I was just reading in the docs where it said Python had *no way* of creating private variables, and I thought: Is that *really* true?

At the very least, it's fair to say that there is no official way.
@Gabriel Pettier
Maurice LéDuck
Someone argued that Python is a language for adults and "private" variables are therefore not needed. There will always be ways to access them anyway but responsible programmers would just leave them alone.
Jonathan Lamothe
@Maurice LéDuck I guess. I just hate polluting my namespaces unecessarily.
@Maurice LéDuck
dn
If the #Python rules and conventions of _ prefixes don't meet the needs for 'privacy', perhaps choose another tool from the tool-box instead of trying to hammer-in a screw?
#python
Jonathan Lamothe
@dn Not my project. I didn't pick the tool.

That said, it was more of a hypothetical question.
@dn

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