# Pastebin 19SqhrnQ
MacBookProRetinaFCO:Injector fernando$ perl6 -e '


multi trait_mod:<is>(Attribute \attr, :$chainable!) is export {
        my \clazz       = attr.package;
        my \type        = attr.type;
        my $meth;       
        if $chainable ~~ Str {
                $meth = $chainable;
        } else {
                $meth   = "set-" ~ attr.name.substr(2);
        }
        note "creating $meth";
        clazz.^add_multi_method($meth, method (\value where * ~~ type) {
                attr.set_value(self, value);
                self
        });     
        clazz.^compose;
}

class Bla {
   has $.ble is chainable;
   has $.bli is chainable; #<blablabla>;
}                                   
                        
my $o = Bla.new;
$o.ble.say;                        
$o.set-ble(1234).say;
$o.ble.say;                                            
$o.set-ble(456).ble.say;

'
creating set-ble
creating set-bli
(Any)
P6opaque: no such attribute '$!bli'
  in block <unit> at -e line 28

MacBookProRetinaFCO:Injector fernando$