gistfile1.txt

class Tree {
    has $.node;
    has $.parent;

    has @.children = [];

    BUILD ($node, @children?) { 
        $.node = $node;
        if (@children) {
            @.children = @children;
            self->_fix_parent;
        }
    }

    method node { $.node }

    method parent ($parent?) {
        if ($parent) { $.parent = $parent; }
        $.parent
    }

    method depth { $.parent ? $.parent->depth + 1 : 0 }

    method traverse (&f) {
        &f->(self);
        @.children->each(-> ($c) { 
            $c->traverse(&f) 
        })
    }

    method _fix_parent { 
        @.children->each(-> ($c) { $c->parent(self) }) 
    }
}

my $t = ^Tree->new("0.0", [
    ^Tree->new("1.0", [
        ^Tree->new("1.1"),
        ^Tree->new("1.2", [
            ^Tree->new("1.2.1"),
            ^Tree->new("1.2.2"),
        ])
    ]),
    ^Tree->new("2.0", [
        ^Tree->new("2.1", [
            ^Tree->new("2.1.1", [
                ^Tree->new("2.1.1.1"),
            ]),
            ^Tree->new("2.1.2", [
                ^Tree->new("2.1.2.1"),
                ^Tree->new("2.1.2.2"),
            ])
        ])
    ]),
    ^Tree->new("3.0"),
]);

$t->traverse(-> ($c) {
   say( (".." x $c->depth), $c->node )
})

gistfile2.txt

class Tree {
    has $.node;
    has $.parent;

    has @.children = [];

    BUILD ($node, @children?) { 
        $.node = $node;
        if (@children) {
            @.children = @children;
            self._fix_parent;
        }
    }

    method node { $.node }

    method parent ($parent?) {
        if ($parent) { $.parent = $parent; }
        $.parent
    }

    method depth { $.parent ? $.parent.depth + 1 : 0 }

    method traverse (&f) {
        &f.(self);
        @.children.each(-> ($c) { 
            $c.traverse(&f) 
        })
    }

    method _fix_parent { 
        @.children.each(-> ($c) { $c.parent(self) }) 
    }
}

my $t = ^Tree.new("0.0", [
    ^Tree.new("1.0", [
        ^Tree.new("1.1"),
        ^Tree.new("1.2", [
            ^Tree.new("1.2.1"),
            ^Tree.new("1.2.2"),
        ])
    ]),
    ^Tree.new("2.0", [
        ^Tree.new("2.1", [
            ^Tree.new("2.1.1", [
                ^Tree.new("2.1.1.1"),
            ]),
            ^Tree.new("2.1.2", [
                ^Tree.new("2.1.2.1"),
                ^Tree.new("2.1.2.2"),
            ])
        ])
    ]),
    ^Tree.new("3.0"),
]);

$t.traverse(-> ($c) {
   say( (".." x $c.depth), $c.node )
})