Course Design Series (Post 1 of N): Why Study Programming Languages

Obviously, there are some practitioners and researchers who base their living on programming language design.  But what of the rest of us?  The Communications of the ACM ran a short article on why: Teach foundational language principles.  Language design is increasingly focused on programmer productivity and correctness.  As programmers, are we aware of the new features and programming paradigms?

Particularly, let's look at three aspects of programming languages: contracts, functional languages, and type systems.  By introducing each to budding programmers, we improve their habits, just as presently I include comments and other style components in project grades.  First, contracts provide a well defined mechanism for specifying the requirements of each component in a system.  Not just commenting each component and interface, but doing so in a manner that permits the compiler / runtime system to verify and enforce it.

Functional languages are well known, and whether or not you may ever use one, they teach valuable techniques and mental models regarding programming.  A programmer should use pure and side-effect free procedures, rather than interleaving logic across different components.  Other practices, such as unit testing, also trend toward clean interfaces; however, being forced to obey these rules via the underlying language is great practice.

Type systems are treated by the authors as a panacea, as they call for language designers to be "educated in the formal foundations of safe programming languages - type systems."  Panacea or not, reasoning about functionality within the bounds of types leads to code that is clearer and more maintainable.  Even in a weak language, such as C, one can use enums rather than everything being "int".

As these aspects are being increasingly used in various forms in current language design, programmers need to be knowledgeable of them in order to be effective and use the languages to their full potential.  It is therefore incumbent on me, and other educators, to appropriately include these aspects when we teach about programming languages.

Which leads me back to writing a course description and learning objectives for my fall course.  Maybe later this month once I figure out why one of the textbooks still hasn't arrived.