`return' in Haskell vs `return' in C,...

Unless you're one of Asimov's technicians of eternity, it is a bit difficult to change the history of programming languages, and assuming that the students pay for the opportunity to learn, you can't really fire them either.. but I agree with Mathias' suggestion to go from the specific to the general. Before anyone complains that abstract and generalised concepts are so much more important and powerful that specific and simplified instances - if you believe this, you will also agree that giving students a chance to learn the general process of abstraction for themselves is more important and empowering than teaching them some specific abstractions. (I'm not sure whether it is even possible to reach all students in a course, but I will certainly not recommend to give up trying;-) One way to look at the problem is that some of your students have concrete experience with `return' in different contexts, and that Haskell tries to make different things look similar here. You say "we worked with monads for several weeks" but, you being yourself, this was probably at a fairly abstract and general level, right? My suggestion is to give your students some concrete experience to counter the one they bring into your course, by introducing the abstract monads via an intermediate step of concrete representations. As you're teaching programming language implementation anyway, why not have an algebraic datatype with return and bind *constructors*, together with some explicit *interpreters* (plural) for the language of structures built from those constructors (even as student exercises)? Perhaps we can gain a better understanding of the student perspective if we compare the situation with lists or other data structures: do we start teaching their folds and the fold-representation of data structures right away, or do we start with concrete intermediate structures, and move on to folds and deforestation later? Of course, with a concrete representation of monads, it is difficult to hold up the law, so after this intermediate step (in which students get their hands on `return' et.al., and in which interpreters can interpret `return a' in any way they please), one can move on to an abstract data type of monads. After all, that's what abstract data types are there for. Hth, Claus