Fractran

“FRACTRAN is a simple theoretical programming language for arithmetic that has none of the defects described above.”
— The FRACTRAN User Manual

What is FRACTRAN?

FRACTRAN is a very simple Turing-complete programming language invented by John Conway. The program consists of a list of fractions. The current state of the prgram is a positive integer. Each step, the state is multiplied by the first fraction such that the result is a whole number.

---

 (Using mouse to drag around a fraction to move/re-order, or drag/drop to garbage/delete bin to remove it.)

Add Fraction 🗑 Delete Reset

Or, load a pre-defined program:
Load — select — primes fibonacci pi poly

Or, load a program from a file:
Load

---

Step Run Stop  (Please input a integer value for N below)

(Running status)

---

Save Save n

A note about file formats

The starting index is separated from the program by a semicolon. The starting index may be left blank. The program’s fractions are separated by commas, and the numerator and denominator are separated by a slash (ex. 144/77). Save it as a .frac, .fc, .fractran, or .txt file.