https://github.com/filipporanza/fractran
A FRACTRAN language interpreter
https://github.com/filipporanza/fractran
conway esolang esoteric-language fractran john-conway
Last synced: 4 months ago
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A FRACTRAN language interpreter
- Host: GitHub
- URL: https://github.com/filipporanza/fractran
- Owner: FilippoRanza
- License: mit
- Created: 2021-08-17T13:05:05.000Z (about 4 years ago)
- Default Branch: main
- Last Pushed: 2021-08-17T21:13:01.000Z (about 4 years ago)
- Last Synced: 2025-04-15T01:47:44.238Z (6 months ago)
- Topics: conway, esolang, esoteric-language, fractran, john-conway
- Language: Rust
- Homepage:
- Size: 12.7 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# fractran
A FRACTRAN language interpreter
## Introduction
FRACTRAN is a Turing-complete esoteric programming language invented
by John Conway in 1987. For more information check [Wikipedia page](https://en.wikipedia.org/wiki/FRACTRAN) and the [original paper](https://link.springer.com/chapter/10.1007/978-1-4612-4808-8_2).
## Installation
```fractran``` should be compiled and installed using [cargo](https://doc.rust-lang.org/cargo/).
In this Section I assume that the reader has basic knowledge about
git and the usage of command line environment.
To compile ```fractran``` clone this repository and then build the binary using:.
```bash
cargo build --release
```
The executable should be in the ```target/release``` directory.
Otherwise you can directly compile and install ```fractran``` by running:
```bash
cargo install --git https://github.com/FilippoRanza/fractran
```
In this case ```cargo``` will automatically move the executable into
the default installation directory.
If you are on Unix remember to strip the executable. Go
to the directory containing the ```fractran``` executable and run:
```bash
strip fractran
```
## Usage
```fractran``` takes its input source code from file given as command line argument.
Running a FRACTRAN program with ```fractran``` is very simple, just call:
```bash
fractran your-src.fractran
```
You can always read the help:
```bash
fractran --help
```
## Language
A FRACTRAN program is an ordered list of fractions and
an initial value. ```fractran``` expects a file written as:
```
init NUMBER
list FRACTION_LIST
```
Where **FRACTION_LIST** is:
```
FRACTION_LIST := FRACTION FRACTION_LIST | FRACTION
```
And **FRACTION** is:
```
FRACTION := NUMBER NUMBER | NUMBER / NUMBER
```
The first **NUMBER** is the numerator, the second is the denominator.
**NUMBER** is an positive integer number (internally a 128 bit unsigned
number).
It is possible to use C style single line and multi line comments.
### Example
The following code implements the multiplication.
```
/*
FRACTRAN multiplication.
*/
init 72 // 72 = 2³ + 3²
list
455 33
11 13
1 11
3 7
11 2
1 3
```
More examples can be found in the ```examples``` directory.