Chapter 16. Interfacing Erlang with Other Programming Languages

It is common for modern computer systems of any size to be built using more than one programming language. Device drivers are typically written in C, and many integrated development environments (IDEs)—such as Eclipse—and other GUI-heavy systems are written in Java or C#. Lightweight web apps can be developed in Ruby and PHP, and Erlang can provide lightweight, fault-tolerant concurrency. If you need to efficiently manipulate or parse strings, Perl or Python is the norm. The library that solves a particular problem for you may not be written in your favorite language, and you must choose whether to use the foreign library or bite the bullet and recode the whole thing in Erlang yourself.^[36]

^[36] This is done for the duplicate code detection algorithm in Wrangler, the Erlang refactoring tool. An existing efficient C library is used to identify candidate “clones” in Erlang software.

Interlanguage communication is never simple in natural languages or in programming. In natural languages, we must understand the different ways in which the languages work. Do they contain articles? Do they denote gender? Where do the verbs occur in a sentence? We also must understand how words translate. Does the verb ser in Portuguese mean the same as “to be” in English, for instance? (It doesn’t.) It’s the same for programming languages. Which paradigm do they come from? Are the languages functional, object-oriented, concurrent, or structured? Is an integer in Java the same thing as an integer in Erlang? (It isn’t!)