tuple-arity

A simple crate for getting the arity (number of elements) of tuple types with 0 to 12 elements.

How to use

You can use the tuple_arity() function to get the arity of an existing tuple value.

use tuple_arity::*;
assert_eq!(0, tuple_arity(&()));
assert_eq!(1, tuple_arity(&("foo",)));
assert_eq!(2, tuple_arity(&("foo", "bar")));
assert_eq!(3, tuple_arity(&("foo", "bar", "baz")));

You can also use the Arity trait to get the arity of a tuple type directly:

use tuple_arity::Arity;

assert_eq!(0, <()>::ARITY);
assert_eq!(1, <(u8,)>::ARITY);
assert_eq!(2, <(u8, u8)>::ARITY);
assert_eq!(3, <(u8, u8, u8)>::ARITY);
assert_eq!(4, <(u8, u8, u8, u8)>::ARITY);