Nested sublanguages of Algol 68 for teaching purposes

Abstract

Two sequences of nested sublanguages of Algol 68 suitable for use in teaching introductory programming are proposed. "A68/k" is a sequence of twelve sublanguages suitable for use in an educational context where the learning of Algol 68 per se is considered important. "SA/k" is a sequence of eight sublanguages suitable for use in a context where the aim is to teach the principles of good programming with minimal concern for the purely linguistic aspects. SA/k is claimed to be superior to other teaching languages such as Pascal.

Lambda: the ultimate sublanguage (experience report)

“…Non-regular types [Bird and Meertens 1998] (often called nested types) -i.e. data types that are applied to something other than their parameters within their own definition -appear frequently in advanced functional programming applications [Bird and Paterson 1999;Hinze 1999Hinze , 2000Okasaki 1998]. Figure 5 gives a typical example: the perfect type constructor appears as ('a,'a) perfect (rather than 'a perfect) in the argument to SuccP; every tree of that type therefore has the form illustrated in the figure, with a chain of n SuccP constructors and exactly 2 n values at the leaves.…”