Brilliant – My Very Own Programming Language

I’ve decided to design and implement my own programming language, and call it Brilliant.

I’ve been interested in programming languages and linguistics almost as long as I’ve been using computers. I’ve long thought that if I ever go back to college, it’s likely that I’ll concentrate on programming languages as a specialty.

My recent discovery and involvement with the Crystal programming language has gotten me excited about new language ideas. It’s also helped me realize that implementing a language myself is feasible, and that there’s no better time to start than now.


For now, the Brilliant implementation doesn’t let you do much more than “Hello World”. But you gotta start somewhere. So this article isn’t really “Introducing Brilliant” so much as the start of a series of articles on its design and implementation.

I wanted to use a PEG (parsing expression grammar) parser for several reasons. For one, they seem to have gained a lot of popularity in the past few years. Also, PEGs cannot be ambiguous, which can solve a few difficult problems, such as the “dangling else“. Perhaps my favorite feature of PEG grammars is that you don’t need a separate tokenizer (lexer). This provides a nice advantage in that we can use keywords like “class” as variables, as long as they’re not used in a place where the keyword would make sense.

So knowing that I wanted to use a PEG, I had to find a PEG parser. I kind of wanted to use ANTLR, which has been a leading parser for many years. But the PEG seems to be new to version 4, and I couldn’t find any Ruby bindings for version 4. Treetop seems to be the most popular parser for Ruby, but I found the EBNF format that Rattler uses to be more to my taste. I think the fact that it’s newer also gives it a few advantages, having had a chance to learn some lessons from Treetop.

I thought about using the Rubinius VM, but decided to go with LLVM, mainly since it has slightly better docs for Ruby, and because it’s what Crystal uses. Also, it’s pretty easy to get it to compile to a binary executable or run in a JIT. In the future, I might consider switching to the Rubinius VM, the Erlang VM, or the Perl 6 VM (Parrot). But for now, I like the idea of being able to compile to a binary and easily interface with C, just like Crystal.


My main goal is to have fun playing around with language ideas.

I’ve found a really great language in Ruby, so I’ll be using it as a starting point. But Ruby does have its faults. In some ways, I want to answer the question “what would Ruby look like if we designed it today?”.

But I also want to explore other ideas. What if objects defaulted to immutable? What if functions and methods were assumed to be pure by default? Might it be possible to infer the purity of a function or method? (If so, we could automatically memoize them.) Can we make creating an actor as easy as creating an object?

I’ll also be looking at ideas from other programming languages. Could we get some of the benefits of Haskell’s purity without having to do somersaults to do IO? Could we mix Python’s indentation style scoping with brace style or begin/end style? Could we integrate Icon’s ideas about success and failure (goal-directed execution)? What interesting features can we pull from Ada, Io, CoffeeScript, Crystal, Rubinius, Perl 6, etc.?

I’m not so much as interested in cutting-edge features, as in features that can be easily used by the average programmer. More importantly, I’m interested in how features interact with each other, so they fit well together to create a whole that’s greater than the sum of the parts.


I wanted to name my programming language “Fermat”. I’ve long been intrigued by Fermat’s Last Theorem, and Fermat’s Little Theorem is important in number theory. Unfortunately, there’s already a computer algebra system with that name.

So I decided to find a name in the same vein as “Ruby” and “Crystal”. I looked at the Wikipedia page for “gemstones” for some inspiration. A lot of the names of gemstones are already taken. I considered some obscure gemstones, but saw the word “brilliant” and thought it was decent. It’s not the name of another gemstone, but still evokes some similarity to Ruby and Crystal.

So that’s the name for now. Perhaps I’ll decide to change it at some point in the future, but I needed a name for the project, as well as a file extension for source code files. I chose “bril” for that. I suppose “br” would be a better choice. Perhaps I’ll change that before the next article in this series.


I hope to work on Brilliant every once in a while. I expect it’ll take a couple years before it’s really very useful.

When I do add a major feature, I’ll be certain to blog about it. I’ve got tons of ideas strewn about in various files. It would be great to get them organized and published —and even better to get them implemented.

One thought on “Brilliant – My Very Own Programming Language”

  1. Cool! Creating a programming language is very fun and you learn a lot in the process. It can sometimes be frustrating and very challenging. The most important thing is to never give up. I’m really curious about the syntax and semantic you have in mind. Good luck!

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