Question

int a, b, n;
...
(a, b) = (2, 3);
// 'a' is now 2 and 'b' is now 3

This sort of thing would be really helpfull in C#. In this example ‘a’ and ‘b’ arn’t encapsulated together such as the X and Y of a position might be. Does this exist in some form?

Below is a less trivial example.

(a, b) = n == 4 ? (2, 3) : (3, n % 2 == 0 ? 1 : 2);

Adam Maras shows in the comments that:

var result = n == 4 ? Tuple.Create(2, 3) : Tuple.Create(3, n % 2 == 0 ? 1 : 2);

Sort of works for the example above however as he then points out it creates a new truple instead of changing the specified values.

Eric Lippert asks for use cases, therefore perhaps:

(a, b, c) = (c, a, b); // swap or reorder on one line
(x, y) = move((x, y), dist, heading);
byte (a, b, c, d, e) = (5, 4, 1, 3, 2);
graphics.(PreferredBackBufferWidth, PreferredBackBufferHeight) = 400;

notallama also has use cases, they are in his answer below.

Answer 1

We have considered supporting a syntactic sugar for tuples but it did not make the bar for C# 4.0. It is unlikely to make the bar for C# 5.0; the C# 5.0 team is pretty busy with getting async/await working right. We will consider it for hypothetical future versions of the language.

If you have a really solid usage case that is compelling, that would help us prioritize the feature.