Duck typing ni kanuni ambapo ufaafu wa object huamuliwa na methods anazozijibu, si class au type yake — "kama anatembea kama bata na analia kama bata, basi ni bata." Katika Ruby, unajali kwamba object anaweza kufanya jambo (ana method), si type yake. Hii huwezesha code rahisi, ya polymorphic bila inheritance au interfaces.
Kanuni: tabia kuliko type
()
duck.quack
=
=
make_it_quack(.new)
make_it_quack(.new)
