Tuple

Forms that compile (10)

Syntax	Description	Note
(int, int) p = (1, 2);	Declaration by position
(int x, int y) p = (1, 2);	Element names
((int, int), int) p = ((1, 2), 3);	Nested tuples
(int a, int b) = Pair();	Deconstructing a return value
(a, b) = (b, a);	Deconstructing assignment to declared variables
(xs[i], xs[j]) = (xs[j], xs[i]);	Deconstructing assignment to array elements
int Take((int, int) p)	Receiving as a parameter
public (int, int) P;	Holding as a field
(int, int)[] ps = new (int, int)[1];	Array element	Elements are read and written as ps[0].Item1.
a == b	Tuple equality

Forms that don’t compile (4)

Syntax	Description	Error	Reason	Alternative
(long, long) b = a;	Convert between tuples element by element	TUKI0099	not yet	Move the elements one at a time (conversions)
((int, int))a	Explicitly convert a tuple	TUKI0099	not yet	Same as above
(int, int)[][] ps = new (int, int)[2][];	Creating a jagged array of tuples	TUKI0001	not yet	Use a 1D array, or hold a separate array per element
(a, b) == (c, d) (tuples of different element types)	Comparing tuples of different element types	TUKI0099	not yet	Convert each element before comparing

How the value is held	It travels as a value, like a struct
Where it can live	Local variables, parameters, return values, fields, array elements

Generation

Declaration by position

Elements declared without names are read as Item1, Item2, and so on.

using UnityEngine;
using Tsukimi;

public class TyTupleDecl : TsukimiBehaviour
{
    void Start()
    {
        (int, int) p = (1, 2);
        Debug.Log(p.Item1);   // => 1
    }
}

Element names

using UnityEngine;
using Tsukimi;

public class TyTupleNamed : TsukimiBehaviour
{
    void Start()
    {
        (int x, int y) p = (1, 2);
        Debug.Log(p.x);   // => 1
    }
}

Nested tuples

using UnityEngine;
using Tsukimi;

public class TyTupleNested : TsukimiBehaviour
{
    void Start()
    {
        ((int, int), int) p = ((1, 2), 3);
        Debug.Log(p.Item2);   // => 3
    }
}

Storage

Deconstructing a return value

using UnityEngine;
using Tsukimi;

public class TyTupleReturn : TsukimiBehaviour
{
    void Start()
    {
        (int a, int b) = Pair();
        Debug.Log(a + b);   // => 3
    }

    private (int, int) Pair() { return (1, 2); }
}

Deconstructing assignment to declared variables

using UnityEngine;
using Tsukimi;

public class TupleAssignExisting : TsukimiBehaviour
{
    void Start()
    {
        int a = 1;
        int b = 2;
        (a, b) = (b, a);
        Debug.Log(a * 10 + b);   // => 21
    }
}

Deconstructing assignment to array elements

The assignment target can also be an array element.

using UnityEngine;
using Tsukimi;

public class TupleAssignArrayElements : TsukimiBehaviour
{
    void Start()
    {
        int[] xs = new int[2];
        xs[0] = 1;
        xs[1] = 2;
        int i = 0;
        int j = 1;
        (xs[i], xs[j]) = (xs[j], xs[i]);
        Debug.Log(xs[0] * 10 + xs[1]);   // => 21
    }
}

Receiving as a parameter

using UnityEngine;
using Tsukimi;

public class TyTupleParam : TsukimiBehaviour
{
    void Start()
    {
        Debug.Log(Take((1, 2)));   // => 1
    }

    private int Take((int, int) p) { return p.Item1; }
}

Holding as a field

using UnityEngine;
using Tsukimi;

public class TyTupleField : TsukimiBehaviour
{
    void Start()
    {
        P = (1, 2);
        Debug.Log(P.Item1);   // => 1
    }

    public (int, int) P;
}

Array element

It can be an array element.

using UnityEngine;
using Tsukimi;

public class TyTupleArray : TsukimiBehaviour
{
    void Start()
    {
        (int, int)[] ps = new (int, int)[1];
        ps[0] = (1, 2);
        Debug.Log(ps[0].Item1);   // => 1
    }
}

Tuple equality

using UnityEngine;
using Tsukimi;

public class ExpressionsTupleEquality : TsukimiBehaviour
{
    void Start()
    {
        (int, int) a = (1, 2);
        (int, int) b = (1, 2);
        Debug.Log(a == b);   // => true
    }
}