Writing an Interpreter and a Compiler in Go

Following along Thorsten Ball's books on writing an interpreter in Go and writing a compiler in Go.

Monkey Language

The monkey language has the following features:

• C-like syntax
• variable bindings
• integers and booleans
• arithmetic expressions
• built-in functions
• first-class and higher-order functions
• closures
• a string data structure
• an array data structure
• a hash data structure

let age = 1;
let name = "Monkey";
let result = 10 * (20/2);
let myArray = [1, 2, 3, 4, 5];
let thorsten = { "name": "Thorsten", "age": 28 };

myArray[0];
thorsten["name"];

let add = fn(a, b) { return a + b; };
let add = fn(a, b) { a + b; };

add(1, 2);

let fibonacci = fn(x) {
    if (x == 0) {
        0
    } else {
        if (x == 1) {
            1
        } else {
            fibonacci(x - 1) + fibonacci(x -2);
        }
    }
};

let twice = fn(f, x) {
    return f(f(x));
}

Interpreter

Major parts of the interpreter:

• lexer
• parser
• abstract syntax tree (AST)
• internal object system
• evaluator