Teaching object-oriented programming on top of functional programming

In the Informatics Programme at the Technical University of Denmark, the authors base the first course in object-oriented programming (using the Java language) on a preceding course in functional programming (using the SML language). The students may hence exploit concepts from functional programming in the construction of OO programs. This is done following a method where the program design is expressed in SML and afterwards implemented in Java. The use of different languages in design and implementation is an advantage as it makes the distinction between these two stages very clear. They give examples showing that SML designs allow them to develop and compare OO implementations with different class structures for the same programming problem. A discussion of this kind is not supported in traditional OO methodology. The program design in SML has also shown to be useful for the students when documenting the program