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FlipJump is the simplest programing language.
Yet, it can do any modern computation.

It's an Esoteric language (FlipJump esolangs page), with just 1 operation a;b:

Which means - Flip a bit, then Jump.

The operation takes 2 memory addresses - it flips (inverts) the bit the first address points to, and jumps to (continue execution from) the second address. The next opcode is the two memory-addresses found right where you jumped to. You flip and jump again, and so on...

This project includes a Macro Assembler, an Interpreter, and a Thoroughly Tested Standard Library for the FlipJump language.
Additionally, it provides a Python Library that makes it easy to work with those components.

This prime numbers program was coded only with FlipJump (source): Printing prime numbers using only FlipJump

Hello, World!

<details> <summary>A simple hello-world flipjump program, not using the standard library:</summary> (jump to the source code)
// define macros that will be used later

// this macro exports the "IO" label to be a global label
def startup @ code_start > IO  {
    ;0              // the second op is reserved for Input/Output.

// this macro gets one parameter "bit", and uses the global label "IO".
def output_bit bit < IO {
    IO + bit;       // flipping IO+0 outputs 0; flipping IO+1 outputs 1.
def output_char ascii {
    // the next line will be unwinded into 8 output_bit macro-uses, each with a different parameter
    rep(8, i) output_bit ((ascii>>i)&1)

def end_loop @ loop_label {
    ;loop_label     // a flipjump program finishes on a self loop

// The first lines of actual code:

    output_char 'H'
    output_char 'e'
    output_char 'l'
    output_char 'l'
    output_char 'o'
    output_char ','
    output_char ' '
    output_char 'W'
    output_char 'o'
    output_char 'r'
    output_char 'l'
    output_char 'd'
    output_char '!'

The source code can be found here: hello_no-stl.fj.

The FlipJump assembly supports a "Hello, World!" syntax for initializing a variable with a string value. Look at the hello_world.fj program for more info.

Note that all of these macros are already implemented in the standard library (all in runlib.fj):


How to install?

pip install flipjump

You can also install it with its extras:

pip install flipjump[stats,tests]

Pycharm Extensions:

How to run?

Use the fj utility:

fj hello_world.fj

Hello World in FlipJump

You can also Test the project with the project's tests, and with your own tests.

You can also assemble and run separately:

fj --asm hello.fj -o hello_world.fjm
fj --run hello_world.fjm

You can also use the faster cpp-based interpreter:

>>> fji hello.fjm -s
Hello, World!

How to Debug?

Programs won't work on their first run. They just can't. That's why we support the next debugging flags.

The debugger can single-step, read-memory, read flipjump variables (bit/hex/byte, and their vectors), continue, or skip forward a fixed number of opcodes.

Get Started with FlipJump

Example usage of the flipjump python library

from pathlib import Path
from flipjump import assemble_and_run  # assemble, run_test_output, ...

fj_file_paths = [Path('path/to/main.fj'), Path('path/to/consts.fj')]
termination_statistics = assemble_and_run(fj_file_paths)

You can also use the flipjump.assemble_run_according_to_cmd_line_args(cmd_line_args=[...]).

Project Structure

flipjump (assembler + interpreter source files):

flipjump/stl (standard library files - macros. The stl readme contains the list of all macros):

programs (flipjump programs, used by the tests), for example:

tests (tests compiling+running the programs with the stl), for example:

Read More - Extra Documentation

Take a look at the other READMEs:

A very extensive explanation can be found on the GitHub wiki page.

More detailed explanation and the specifications of the FlipJump assembly can be found on the FlipJump esolangs page.

If you are new to FlipJump and you want to learn how modern computation can be executed using FlipJump, and you want to jump onto your first flipjump code - Start by reading the bit.xor and bit.if macros. That's where the FlipJump magic begins.
If you want to understand how the deep optimized hex macros work, understand how the next macros are implemented: hex.exact_xor, hex.output, hex.inc1, and hex.add (understand the concept of the lookup tables.

You can also write and run programs for yourself! It is just that easy :)

Turing Complete?

As the language expects a finite memory, like most of today's programming languages, it's technically not Turing complete. Yet, It's very capable.

I wrote a Brainfuck to Flipjump Compiler (bf2fj) to emphasize just that. Brainfuck is indeed Turing complete, and the compiler proves that flipjump can run any program that brainfuck runs (besides those that require an unbounded memory).


If you want to contribute to this project, read the CONTRIBUTING.md file, and take a look at the I-Want-To-Contribute Thread.

Actually, just writing your own flipjump programs and sharing them with the world is a great contribution to the community :)
Take a look at what the standard library offers, and see some example programs to get you inspired!