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Tuples

TinyCLR supports Tuple and ValueTuple — a quick way to group a few values without declaring a class, including tuple deconstruction. They live in the core runtime (GHIElectronics.TinyCLR.Core).

  • Tuple is a reference type (class). Its Item1, Item2, … are read-only.
  • ValueTuple is a value type (struct). Its items are mutable fields, and it's the type that deconstructs with var (a, b) = ….

Both compare by value (two tuples with equal items are equal) and support 1 to 7 elements.

Tuple​

using System;
using System.Diagnostics;

var t = Tuple.Create(42, "answer");          // Tuple<int, string>
Debug.WriteLine(t.Item1 + " = " + t.Item2);  // 42 = answer

// Equal by value, so they also work as dictionary keys.
var a = Tuple.Create("x", 1);
var b = Tuple.Create("x", 1);
Debug.WriteLine(a.Equals(b));                // True

A handy use is returning more than one value from a method:

static Tuple<int, int> DivRem(int dividend, int divisor) =>
    Tuple.Create(dividend / divisor, dividend % divisor);

var dr = DivRem(17, 5);
Debug.WriteLine(dr.Item1 + " remainder " + dr.Item2);   // 3 remainder 2

Because tuples compare by value, one can serve as a Dictionary key:

using System.Collections.Generic;

var grid = new Dictionary<Tuple<int, int>, string>();
grid[Tuple.Create(1, 2)] = "cell-1-2";
Debug.WriteLine(grid[Tuple.Create(1, 2)]);   // cell-1-2 (a fresh, equal tuple matches)

ValueTuple​

ValueTuple is a lightweight struct that pulls apart into separate variables:

var vt = ValueTuple.Create("hello", 5);
var (greeting, length) = vt;                 // deconstruction
Debug.WriteLine(greeting + " / " + length);  // hello / 5

This shines for methods that return a couple of related values — the caller deconstructs the result inline:

static ValueTuple<int, string> StatusAndMessage(int code) =>
    ValueTuple.Create(code, code == 200 ? "OK" : "Error");

var (code, message) = StatusAndMessage(200);
Debug.WriteLine(code + " " + message);       // 200 OK
note

Tuples support 1 to 7 elements. The 8-or-more element nested ("TRest") form is not included — see Limitations. For more than seven values, use a small class or struct.