Macro swap_at 

swap_at!() { /* proc-macro */ }

Swap two parts of a tuple.

Syntax

IndicesGroup      = Index [ - Index ]

swap_at!(Expr; IndicesGroup1 , IndicesGroup2 )

[ and ] only indicate the optional content but not that they need to be input.

The index must be an integer literal since procedural macros do not yet support evaluating constants.

Explanation

You can swap two elements of a tuple, then generating a new tuple:

use tuplez::{swap_at, tuple};

let tup = tuple!(1, "2", 3.14, [1, 2, 3], Some(9.8), 'c', 14);
let tup2 = swap_at!(tup; 0, 4);
assert_eq!(tup2, tuple!(Some(9.8), "2", 3.14, [1, 2, 3], 1, 'c', 14));

You can also specify a continuous range of elements via start - end, but the number of elements on both sides must be equal:

use tuplez::{swap_at, tuple};

let tup = tuple!(1, "2", 3.14, [1, 2, 3], Some(9.8), 'c', 14);
let tup2 = swap_at!(tup; 0-2, 3-5);
assert_eq!(tup2, tuple!([1, 2, 3], Some(9.8), 'c', 1, "2", 3.14, 14));

Of course, reverse ranges are also supported:

use tuplez::{swap_at, tuple};

let tup = tuple!(1, "2", 3.14, [1, 2, 3], Some(9.8), 'c', 14);
let tup2 = swap_at!(tup; 0-2, 5-3);
assert_eq!(tup2, tuple!('c', Some(9.8), [1, 2, 3], 3.14, "2", 1, 14));