Name of process of using multiple languages together

Question

I'm wondering what is the formal name of process of using multiple languages together. Lets say I'm writing a program in C++ which calls Java functions (and uses Java libraries) and sometimes calls Python functions. Then it gathers the results from those calls and continues execution.

How would you name this process?

Answer 1

Depending on how many different languages you use, how small the subproblems are for which you use different languages, how specific those languages are for the subproblem at hand, and how many of those languages you designed yourself to solve that specific subproblem, it might be called Language-Oriented Programming, Polyglot Programming or just Programming.

For example, just using C++ you actually use three languages: C++ itself, the C++ template language (which is basically a hybrid functional / logic programming language) and the C++ macro language. Throw in make and sh for building, JSON for configuration, roff for documenting, and Tcl for testing, and you are looking at 8 languages. However, I would just call that normal Programming, nothing special about it. The same applies to a typical web project combining HTML, CSS, ECMAScript, JSON, SQL, Java, XML, sh.

Language-Oriented Programming is at the other end of the spectrum. In LOP, you break your problem apart into ever smaller subproblems, sub-subproblems and so on, and then you solve every subproblem with a language that is most suited for that particular subproblem, possibly one you designed specifically for that subproblem. Basically, in LOP, you use Languages the same way you use Objects in OOP, Procedures in PP, Functions in FP and so on. Typically, those languages are Domain-Specific and often not Turing-complete.

Polyglot Programming is somewhere in the middle: you use different languages for different larger components, but not a the same level of abstraction as, say, individual objects, and you usually use pre-existing Turing-complete general-purpose languages, instead of designing them yourself. For example, trend.ly used "Smalltalk for thinking, Java for brute-force computing, ECMAScript for visualizing, Ruby for gluing those three together and sh for deployment". Your description sounds most like Polyglot Programming to me.

Note that those definitions are very subjective: for example, in Lisp, designing and implementing new languages is so obvious, natural and trivial, that no Lisp programmer would call what he does "Language-Oriented Programming". They just call it "Programming".

I wouldn't put a hard and fast rule on it, saying "between 5 and 10 languages it's Polyglot, more is Language-Oriented, less is just Programming". It's more a mindset: when you look at a problem, what's the first thing that comes to mind "How can I solve this in this language", "What would be the best language to solve this in" or "What would the perfect language to solve this problem in look like"?

Answer 2

It's called polyglot programming.