Hi, the following seems to do the trick (?) : Le 28 mars 10 à 18:38, Dario Teixeira a écrit : > let rec step1 ?story () = match story with > | Some s -> step2 s#title > | None -> step2 "title1" > > > and step2 title = > let story = > object > method title = title > method count = 0 > end > in step3 ~story > > > and step3 ~story = match story#count with > | 0 -> >> - step1 ~story () + step1 ~story:(story :>