The Noja language

1. Introduction
2. Objective
3. Show me the code!
4. Implementation overview
5. Supported platforms
6. Development state
7. Build
8. Usage

Introduction

This language was written as a personal study of how interpreters and compilers work. For this reason, the language is very basic. One of the main inspirations was CPython.

Noja is a very high level and dynamic language. It operates in the same range of abstraction as languages like Ruby, Python and Javascript.

Objective

This project aims at being an interpreter design reference, therefore it optimizes for code quality and readability. That's not to mean that it won't be feature-complete. The end goal is to have a language you can do arbitrarily complex things in.

Show me the code!

Here's an example of a noja program that orders the items in list using a bubble sort

L = [3, 2, 1];

do {
    swapped = false;

    i = 0;
    while i < count(L)-1 and not swapped: {

        if L[i+1] < L[i]: {
        
            swapped = true;
            tmp = L[i+1];
            L[i+1] = L[i];
            L[i] = tmp;
        }
        
        i = i + 1;
    }
} while swapped;

print(L, '\n'); # Outputs [1, 2, 3]

Implementation Overview

The architecture is pretty much the same as CPython. The source code is executed by compilig it to bytecode. The bytecode is much more high level than what the CPU understands, it's more like a serialized version of the AST. For example, some bytecode instructions refer to variables by names, which means the compiler does very little static analisys. Memory is managed by a garbage collector that moves and compacts allocations.

(More detailed explanations are provided alongside the code.)

Supported platforms

I wrote it on a linux machine, but there should be very few places where a linux host is assumed. It should be very easy to port.

Development state

The interpreter is fully functional, but lots of built-in functions that one would expect still need to be implemented. Unfortunately, I feel like, at the moment, this requires much more work than what it's worth. At this time the priority is writing documentation and tests so that more people can try it, give feedback and move forward without breaking the world.

Build

To build it, just run:

$ ./build.sh

it will create a build folder where the interpreter's executable will be generated.

You may need to give executable permissions to the script. You can do so with by running:

$ chmod +x build.sh

Usage

You can run files by doing:

location/of/noja run <filename>

or you can run strings by doing:

location/of/noja run inline <string>