my-interpreter-in-python

This implements the interpreter from the video series: https://www.youtube.com/playlist?list=PL_2VhOvlMk4UHGqYCLWc6GO8FaPl8fQTh but in Python.

But it also adds if-else conditionals and while-break-continue looping.

To run the interpreter - REPL mode

It comes with its REPL. Just run the main.py with:

$ python3 main.py

To run the interpreter - File mode

It can also run a file with the code for the language. You just create a file called object.txt and replace the repl() with run() in the main.py. And run:

$ python3 main.py

Using the Language

Binary Operations

Here are examples of binary operations:

Addition, Subtraction, Multiplication, Division, Modulus:

> 1 + 1
{ value: 2 }
> 1 - 1
{ value: 0 }
> 1 * 1
{ value: 1 }
> 1 / 1
{ value: 1 }
> 1 % 1
{ value: 0 }

Mixing it up:

> 2 * 1 - 1 * 1
{ value: 1 }

Comparison:

> 2 > 1
{ value: "true" }
> 2 == 2
{ value: "true" }
> 2 != 1
{ value: "true" }

Logical:

> 2 > 1 && 1 > 2
{ value: "false" }

String Addition:

> let x: string = "Hello";
{ type: "string", value: "Hello" }
> x = x + ", World!"
{ type: "string", value: "Hello, World!" }

Declare Variable

We can declare a variable and then reassign it Declare Mutable Variable as a primitive and reassign:

> let x: number = 1;
{ value: 1 }
> x = 2
{ value: 2 }

Declare Constants:

> const x: number = 1;
{ value: 1 }

Declare Mutable Variable as an object:

> let x: {a: number, b: number} = { a: 1, b: 2 };

Reassign member value:

> x.a = 2

Declare Function

We can declare a function Declare a function:

> fn add(x, y) { x + y }
> add(1, 2)
{ value: 3 }

Conditionals

We can use if-else statements If-Else:

let x = 1;
> if (1 > 2) { x = 2 } else { x = 1 }

Loops

We can use while-break-continue statements While-Break-Continue:

> let x = 2;
{ value: 2 }
> while (x > 1) { x = x - 1 }
> while (1 == 1) { break }

Why build this?

I loved the bhai-lang project and wanted to run how to build an interpreter. This led me to the video series, which uses typescript. But I wanted it to be available to all folks who love Python like me, so I have written the entire thing in Python. Not only that, the video series doesn't implement if-else conditionals, or while-break-continue looping construct, which I do. Enjoy learning!