Charta

A 2D concatenative programming language.

fn fibo (n : int) -> (int) {
→ 0 1 ↻ 1 - ⇈ 0 > ? ◌
                  ↓
                  ↷
                  ⊼
                  ⊼
      ↑     ◌ ↻ + ←
}

fn main () -> () {
→ 40 fibo print
}

Introduction

Charta is a concatenative language. Operations follow Reverse Polish Notation, i.e. 2 + 3 is written as 2 3 +. This also means that, if you want to apply two functions back-to-back, f(g(x)), then you can naturally compose / concatenate your functions x g f.

Charta is also a 2D language. Your program starts evaluating from the top-left of a function and moves in the directions specified by the arrows ←, →, ↑, ↓ until it exits the grid (and thus the function / program). You can change your direction conditionally with ?. If the previous expression evaluated to true, that is if the top of your stack has true, then ? rotates you to a specified perpendicular direction. Using just ? and directional arrows, you can express control flow like loops and conditionals. Since control flow is only written explicitly with arrows, code reads like a flow chart.

Want to learn more? Check the docs

Building the project

With GNU Make:

make all

With CMake:

cmake -Bbuild && cmake --build build

NOTE: Ensure that you preserve the file structure of charta, core/core.h and libcore.a!

.
├── charta
├── core
│   └── core.h
└── libcore.a

TODO: ↑ Make an install script for this step