gistfile1.txt

class Person    is Entity does Location { }
class Place     is Entity does Location { }
class Thing     is Entity does Lendable { }
class Container is Entity does Lendable does Location { }

...



class Command::info is Command::Unary {
    sub show-contents(Entity $entity where Location) {
        my Entity @items = Entity.all-entities.grep(Lendable)
            .grep({ .location && .location.id.lc eq $entity.id.lc });
            
        put "$entity has { +@items } {
            @items == 0 ?? 'items.' !! @items == 1 ?? 'item:' !! 'items:' }";
        put yellow("* "), $_ for @items;
    }   
    sub show-location(Entity $entity where Lendable) {
        my $location = $entity.location;
        
        without $location {
            put "I don't know where $entity is.";
            return;
        }   
        
        put "$entity is currently at $location.";
        Command::info.execute: $location if $location ~~ Lendable;
    }   
    method execute(Entity $entity) {
        show-contents $entity if $entity ~~ Location;
        show-location $entity if $entity ~~ Lendable;
    }   
}