Course of Raku / Addendum 🆕 / Types and text machines / Objects and classes / Exercises / Adding vectors

Solution: Adding vectors

Here is a possible solution to the task.

Code

class Vector {
    has $.x;
    has $.y;

    method add(Vector $v) {
        Vector.new(x => $.x + $v.x, y => $.y + $v.y);
    }

    method Str { "($.x, $.y)" }
}

my $sum = Vector.new(x => 1, y => 2).add(Vector.new(x => 3, y => 4));

put $sum;

🦋 You can find the source code in the file vector-add.raku.

Output

(4, 6)

Comments

1. add does not change either vector; it constructs and returns a brand-new Vector from the summed components.

2. Notice that Vector is used inside its own definition — as the parameter type Vector $v and in Vector.new. That is perfectly fine: the type name is known from the moment its declaration starts, so a class can freely refer to itself in its own methods. There is no need for any kind of forward declaration.

3. put stringifies its argument with the Str method, so the custom "($.x, $.y)" formatting is what appears.

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