Discovering Functional Programming Through Imperative Languages

The pedagogical desirability of functional programming is effectively swamped by an overwhelmingly imperative‐language‐oriented culture. Because a meaningful subset of the functional paradigm is accessible within imperative languages, it is possible to identify a subset of Modula‐2 that characterizes the functional paradigm subset. A series of list‐processing problems and their solutions in the Modula‐2 subset provides students with ample exposure to the practice and theory of functional programming. Extension to the full functional paradigm and migration to specialized functional languages are managed, in the worst case by initial pseudo‐Modula‐2 programming involving hypothetical extensions supporting higher‐order functions and polymorphism. More powerful solutions to this problem are foreshadowed, in the form of preprocessor implementations of Modula‐2‐ and Ada‐derivative functional languages.