Monkey programming language

This is an interpreter written in Golang following "Writing An Interpreter In Go". The purpose for the project was personal education.

If you want to try it, without downloading anything, you can here.

Language Specifications

Monkey have the following set of 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

Monkey has the following syntax:

// Give values names
let age = 1;
let name = "Monkey";
let result = 10 * (20 / 2);

// Arrays
let myArray = [1, 2, 3, 4, 5];
myArray[0] // => 1

// Hashes
let thorsten = {"name": "Thorsten", "age": 28};
thorsten["name"] // => "Thorsten"

// Functions
let add = fn(a, b) { return a + b; };
add(1,2); // => 2

// Builtins
len(myArray) // => 5
puts("Hello") // => Hello
first(myArray) // => 1
last(myArray) // => 5
rest(myArray) // => [2, 3, 4, 5]
push(myArray, 6) // => [1, 2, 3, 4, 5, 6]

Next steps

Only reading and understanding some code is fine, but not enough for me, therefore I will be using this as a starting point to expand.

Additional features

The intention is to add OOP, to be more specific:

• Class keyword
• Class initialization
• Inheritance
• Polymorphism
• Encapsulation

Additional syntax

// Class example
class A {
    let a = 5;

    let method = fn () {
        return 3;
    };
};
let a = new A();
a.a; // => 5
a.method(); // => 3

// Inheritance
class B : A {
    let b = 6;

    let method2 = fn () {
        return 4;
    };
};
let b = B();
b.a; // => 5
b.b; // => 6
b.method2(); // => 4

// Polymorphism
class C : A {
    let method = fn() { return 7 };
};
let c = C();
c.method() // => 7

// Half encapsulation
class D {
    private let d;

    let getD = fn() {
        return this.d;
    };
};
let d = new D();
d.d; // error
d.getD(); // => 5

Unfortunately assign operation is not supported by the language, I could add it... but I feel educated enough, time to move forward.

Run

To run the repl:

go run main.go

To run the server on localhost:8080:

docker build --tag code-server .
docker run --publish 8080:8080 code-server