RustTutorials/2.Primitives/2Tuples.rs

use std::fmt;	//Import 'fmt'


//Tuples can be used as function arguments and as return values
fn reverse(pair: (i32, bool)) -> (bool, i32){
	//`let` can be used to bind the members of a tuple to variables
	let (integer, boolean) = pair;

	(boolean, integer)
}

//The following struct is for the activity.
#[derive(Debug)]
struct Matrix(f32, f32, f32, f32);
impl fmt::Display for Matrix{
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result{
		write!(f, "( {} {} )\n( {} {} )", self.0, self.1, self.2, self.3)
	}
}
fn transpose(matrix: Matrix) -> Matrix{
	#[allow(non_snake_case)]
	let newMatrix = Matrix(matrix.0, matrix.2, matrix.1, matrix.3);
	return newMatrix;
}

fn main(){
	//A tuple with a bunch of different types
	let long_tuple = (1u8, 2u16, 3u32, 4u64,
					  -1i8, -2i16, -3i32, -4i64,
					  0.1f32, 0.2f64,
					  'a', true);

	//Values can be extracted from the tuple using tuple indexing
	println!("long tuple first value: {}", long_tuple.0);
	println!("long tuple second value: {}", long_tuple.1);

	//Tuples can be tuple members
	let tuple_of_tuples = ((1u8, 2u16, 2u32), (4u64, -1i8), -2i16);

	//Tuples are printable
	println!("tuple of tuples: {:?}", tuple_of_tuples);
	
	//But long Tuples cannot be printed
	//let too_long_tuple = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13);
	//println!("too long tuple: {:?}", too_long_tuple);
	//TODO ^ Uncomment the above 2 lines to see the compiler error

	let pair = (1, true);
	println!("pair is {:?}", pair);

	println!("the reversed pair is {:?}", reverse(pair));

	//To create one element tuples, the comma is required to tell them apart from a literal surrounded by parentheses
	println!("one element tuple: {:?}", (5u32,));
	println!("just an integer: {:?}", (5u32));

	//tuples can be destructured to create bindings
	let tuple = (1, "hello", 4.5, true);

	let (a, b, c, d) = tuple;
	println!("{:?}, {:?}, {:?}, {:?}", a, b, c, d);

	let matrix = Matrix(1.1, 1.2, 2.1, 2.2);
	println!("Debug:\n{:?}", matrix);
	println!("Matrix:\n{}", matrix);
	println!("Transpose:\n{}", transpose(matrix));
}