Nim: Adding a ".nogc." pragma

[wizzardx]

Functions annotated with ".nogc." can't do any operations that rely on garbage collection.

Similar to how nogc works in D lang:

https://wiki.dlang.org/DIP60

Implementation would probably be similar to how the ".noSideEffect." pragma already works in Nim.

[Araq]

And then what? What's the point? We have --gc:none and looking at the compiler warnings.

[wizzardx]

The point - A larger subset of Nim stdlib and ecosystem being usable in environments where GC is not acceptable. eg, domains where only C, C++, Rust or Ada may be used.

It would be like "--gc:none" that always becomes a compile error if a given function has that pragma.

But you're right, given that "--gc:none" is available, it's a lot less relevant. People can make github pull requests, or make their own modules where "--gc:none" doesn't give any warnings, for those kinds of environments.

Thanks for the reminder!

[yglukhov]

That may be useful for e.g. games, where you want to avoid gc in rendering logic, but ok with gc in game logic. noSideEffect is a nice analogy. You don't want to compile all program with noSideEffect.

[Araq]

Not gonna happen anytime soon.