Motivations for writing your own programming language

Sure, some programming language inventors are rock stars of computer science, such as Dennis Ritchie or Guido van Rossum! Becoming a rock star in computer science was easier back in the previous century. In 1993, I heard the following report from an attendee of the second ACM History of Programming Languages Conference: “The consensus was that the field of programming languages is dead. All the important languages have been invented already.” This was proven wildly wrong a year or two later when Java hit the scene, and perhaps a dozen times since then when important languages such as Go emerged. After a mere six decades, it would be unwise to claim our field is mature and that there’s nothing new to invent that might make you famous.

In any case, celebrity is a bad reason to build a programming language. The chances of acquiring fame or fortune from your programming language invention are slim. Curiosity and a desire to know how things work are valid reasons, so long as you’ve got the time and inclination, but perhaps the best reason to build your own programming language is necessity.

Some folks need to build a new language, or a new implementation of an existing programming language, to target a new processor or compete with a rival company. If that’s not you, then perhaps you’ve looked at the best languages (and compilers or interpreters) available for some domain that you are developing programs for, and they are missing some key features for what you are doing, and those missing features are causing you pain. This is the stuff Master’s theses and PhD dissertations are made of. Every once in a blue moon, someone comes up with a whole new style of computing for which a new programming paradigm requires a new language.

While we are discussing your motivations for building a language, let’s also talk about the different kinds of languages, how they are organized, and the examples this book will use to guide you.