What? We’ve had blog posts about the fact that we’re writing Spycursion in Lisp. Some call it secret alien technology. Okay, full disclosure: Lisp as a computing language was created on Earth by a human (his name was John McCarthy) back in the late 1950s. I can’t say whether or not he was inspired by beings from another world. I don’t know for sure, and even if I did, it would be a secret. I would never say. What I do know is that there is a great deal of power packed into the elegant and surprisingly simple programming language known as Lisp. Every few years, we see more modern languages (say, C++, Java, or Python) bringing in “novel” programming constructs into newer releases of the language. Yet, these exciting new constructs are frequently taken from Lisp and often have been part of Lisp since darn near the beginning.
So, it’s a great language if you’re a programmer willing to venture outside the proverbial box. But why did I start off talking about Lisps, plural, as if there were more than one? Simple: there is more than one. In fact there are many. Lisp is actually a family of programming languages. A Lisp can be quite different from other Lisps in much the same way that C++, Java, and Python are different from each other. (If you’re curious, those languages all belong to what could be called the Algol family.) What we have been generally referring to as Lisp is actually a language called Common Lisp, which is the result of an effort to consolidate features from many of the earlier Lisps into one standardized language. Common Lisp is a powerful choice, which allows our tiny team of developers to deliver you a great big gaming experience full of secrets, intrigue, and espionage in a dystopian world just waiting for you to leave your own unique mark on it.
But Spycursion is an MMO. For the three of you who don’t already know it, that means “massively multiplayer online” game. We would like you to know that we are taking that first M very seriously. No doubt you have heard about some online service that fell to its knees at some point because a mass of people all tried to connect to it at the same time. I remember, as a keen example, an evening in recent history when newscasters were reporting the increasingly certain result for a presidential election in the United States. So many people in the country were frightened by the outcome that the Canadian immigration website eventually went down that night. Some people thought this funny. Others thought it worrisome. I thought, Canada did not program its immigration website in Erlang.
So, what’s an Erlang? It’s not a Lisp (though that would certainly have been a sharp guess). It is, however, a programming language and an extremely powerful one at that, just not in the same way that Lisp is known to be powerful. Erlang was not designed to be a general purpose language with Lispy features that lets a tiny development team like ours mould the language itself into the perfect tool to build Spycursion for all of you. Erlang was designed specifically so that when hundreds of thousands (or dare we imagine, millions) of you all decide to play Spycursion at the same time, our servers don’t fall flat as if they had nothing more important to do than to provide information about immigration to Canada to panicking voters.
Erlang is a programming language whose central purpose is to do a massive number of tasks at the same time and also to create systems that never go down, ever. The downside of a language that strives to achieve what no other programming language can is that it is not general-purpose like Common Lisp. Erlang is primarily a server-side language, and so we aren’t really aiming to keep your own personal computer running. Rather, we want to make sure the computers responsible for providing you access to the world of Spycursion are able to keep that world available to you, even if you all decide to enter the game at the same time, even when we have to update our systems, even if we have hardware issues, and even if one of us has somehow missed a bug in our code. (There’s less chance of that in Erlang, but it still happens to the best of us.)
Yet, as we said, Erlang is not a Lisp. We are (defun games ()), which has Lisp right there in the name. (And we’ll give one month of free game play to the first 8 people who figure out how that makes any sense.) Sure the Spycursion client you enjoy on your computer is powered by Common Lisp, but we also want that Lispy goodness on the server side so we can fine-tune our programming language and bring you the best game possible. Unfortunately, there is almost always a trade-off when making design decisions about programming languages. If only Erlang were a Lisp so that we could harness the superpowers of both languages at the same time.
Now I am guessing that perhaps at most three of you have heard of LFE. It may be more of that secret alien technology, but it too was created on Earth by a human (his name is Robert Virding) back in the mid 2000s. LFE stands for Lisp Flavoured Erlang. As the name implies, we have Lisp and Erlang in a single programming language. We at (defun games ()) feel that it truly represents the best of both worlds. We can use the power of a Lisp to extend the language so that it is not only a gaming language, but a language oriented specifically for Spycursion. At the same time we can build the world of Spycursion on the solidly reliable and massively parallel foundation that comes with an Erlang-based application.
So, how many Lisps do we need? To provide you the best massively multiplayer online gaming experience we possibly can, we need two: Lisp Flavoured Erlang to serve you en masse and Common Lisp so we can delight you individually.