A simple FRACTRAN interpreter written in Koka.

FRACTRAN is a Turing-complete esoteric programming language invented by the mathematician John Conway. A FRACTRAN program is an ordered list of positive fractions, together with an initial positive integer $n$.

The program is run by updating the integer $n$ as follows:

1. For the first fraction $f$ in the list for which $nf$ is an integer, replace $n$ by $nf$.
2. Repeat this rule until no fraction in the list, when multiplied by $n$, produces an integer, then halt.

• Koka compiler

Clone the repository:

git clone https://github.com/yourusername/fractran-koka.git
cd fractran-koka

You can run the interpreter using the Koka compiler:

koka src/main.kk -- examples/mul.frac 12

Or build an executable:

koka -o fractran src/main.kk
./fractran examples/mul.frac 12

The examples/ directory contains some sample FRACTRAN programs:

• mul.frac: Multiplication program.
• prime.frac: Conway's prime-generating program.
• sample.frac: A simple test program.

• src/: Source code in Koka.
  • fractran.kk: The core FRACTRAN library.
  • main.kk: CLI entry point.
• examples/: Sample FRACTRAN programs.

This project is licensed under the MIT License - see the LICENSE file for details.