Are there any ways to recursively flatten tuples?

Question

In Rust, is there any way to use traits and impls to (recursively) flatten tuples?

If it helps, something that works with N nested pairs is

Answer 1

I implemented this with specialization and auto trait.

docs.rs

github repo

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Usage is basically

assert_eq!((1, (2, ((3,) (4, 5)), (), 6).flatten(), (1, 2, 3, 4, 5, 6));

It removes all empty unit tuple () (like python).

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If you are writing generic code, you need to add

where (A, B): Flatten

rustc wants this because Flatten is implemented only if length of output tuple is smaller than 13.