tuple-types.md

Tuple Types

The tuple types are a family of generic types. Like the simple types, they are identified by the keyword "Tuple". A tuple is an ordered list of values that can be of different types.

Tuples are const value types. This does mean that a tuple cannot contain an iso or owned type. In fact, all generic arguments must be aliasable. Tuples are conditional drop types and can contain drop types.

tuple_type
    : "Tuple" "[" type{",", 0, *} "]"
    ;

TODO: allow large tuples to be partially reference types

Tuple Size

The number of values in a tuple can be accessed using the "count" field which is of type "size".

Tuple Initializer

Tuples can be constructed using the tuple initializer syntax.

let t = #(1, "something"); // t: Tuple[int, string]

Destructing With let

The individual fields of a tuple can be accessed using a destructuring pattern.

let x, y, z = #(1, 2, 3);
console.WriteLine("x = \(x)");

Indexing Tuples

Tuple fields can also be accessed by a zero based index. This is consistent with collections which are zero based. Tuple values can be directly accessed as properties by escaping the index name.

let t = #(1, 2, 3);

let x = t.\0;
let y = t.\1;
let z = t.\2;