How To Make A Programming Language

Ever wanted to create your own programming language?

Table Of Contents

• Index <- You are here.
• ANTLR4 Setup
• ANTLR4 Grammar
• Creating Toylet
• Project Setup
• LLVM Crashcourse
• Compiling Toylet
• Epilogue

Introduction

This is hard. Of course, it depends on how complex you want your language to be, but in general, this will not be a simple task and it may be confusing at some points. Hopefully with this guide, you’ll have a better idea on how to implement your language. In this tutorial, I will be utilizing modern technologies such as ANTLR4 and LLVM at the time of writing, which luckily do a lot of the grunt work for us. So with that said, let’s get started!

Our Language

The first step of making a programming language is to first write some sample code to explore the syntax. In this tutorial, we will be implemented a toy language with no practical purpose called Toylet.

func doThing(number num, string str, decimal dec) {
    number a = num + 5 * 3 - 1;
    a += (number)dec;
    println(str + a);
}

doThing(3, "Result: ", 5.7);

As you can see, this contains a few concepts you would use in a language, such as data types, functions, operations, string concatting, and casting.

Roadmap

As you probably guessed, making a language has a lot of different parts. Let’s go over the main points of interest:

• Defining the syntax of our language. I’m telling you how Toylet works, so this step is done.
• Converting input into an Abstract Syntax Tree (AST). In order to do something with any program, we have to convert it into a form the compiler can work with, We call this the AST. We will be using ANTLR4 to handle this. We first must learn ANTLR4, then write a grammar for our language.
• Compile AST into code. Using the AST, we will make sure the code is valid while compiling. When we compile, we will convert the AST into LLVM IR, which is a very low-level, assembly like language. While you could learn LLVM IR syntax, all we need to know is how to work with it and emit it. Once in this form, LLVM can optimize our code, run it in a virtual machine using a bytecode, or compile it as a native binary for any platforms supported by LLVM!

Next

Next thing to do is to set up ANTLR! ANTLR4 Setup