Course of Raku / Addendum 🆕 / Types and text machines / Objects and classes / Exercises / A stack class

Solution: A stack class

Here is a possible solution to the task.

Code

class Stack {
    has @!items;

    method push($x) { @!items.push($x) }
    method pop      { @!items.pop }
    method peek     { @!items.tail }
    method size     { @!items.elems }
}

my $stack = Stack.new;
$stack.push($_) for 1, 2, 3;

say $stack.peek;
say $stack.pop;
say $stack.size;

🦋 You can find the source code in the file stack.raku.

Output

3
3
2

Comments

@!items is a private attribute — the ! twigil means it is reachable only from inside the class, which is exactly what a stack’s storage should be.
peek uses .tail to look at the last element without removing it, while pop actually takes it off, so the size drops from 3 to 2.

← A stack class | A bank account →