Traits: Composable Units of Behaviour Nathanael Sch¨arli, St´ephane Ducasse, Oscar Nierstrasz, and Andrew P. Black Software Composition Group, University of Bern, Switzerland OGI School of Science & Engineering, Oregon Health and Science University {schaerli, ducasse, oscar}@iam.unibe.ch, black@cse.ogi.edu Published in ECOOP’2003, LNCS 2743, pp. 248–274, Springer Verlag, 2003 Abstract. Despite th