A data pack implementing the esoteric programming language BackFlip, which is vaguely similar to the Langton's Ant cellular automaton

Designed for Minecraft 1.19.4

Programs are built horizontally out of blocks, and a special armor stand is used as a pointer to move over the program and evaluate it. Since the basic operations of BackFlip are reversable, programs can also be run in reverse, which in Minecraft can be useful for resetting the program's state

Syntax

• Arrow - Magenta glazed terracotta - Changes the pointer's direction of movement (as indicated by the arrow shape on the default texture), and then turns to face opposite the direction the pointer was going previously
• Mirror - Pink glazed terracotta - Reflects the pointer's direction of movement against a diagonal (as suggested by the diagonal shape on the default texture), and then switches to the other mirror orientation
• Output - Wool - Reverses the pointer's direction of movement
  • Digits 0-9 are output by red, orange, yellow, lime, cyan, light blue, blue, purple, magenta, and pink wool respectively
  • A line ending is output by black or white wool
  • Other colors of wool also have the rebound behavior, but don't produce output
• Empty space - Concrete
• Anything else - Considered to be outside of the program and causes the program to terminate

Notes on output

• Output is given in the chat; in order to display it neatly in lines, nothing is output until a line ending is reached or the program terminates
  
• Because of how output works, there's not a good way to reverse output operations, so running a program partially backward and then forward again may cause some duplicated output data (however, output is reset once the program is fully rewound to the beginning)

Useful commands

(Cheats need to be enabled in order to use the data pack)

All of these will target the nearest pointer within 90 blocks

• /function arcbkf:init
  Initializes a pointer at the current location, facing in the current direction
• /function arcbkf:run
  Runs the program
  
• /function arcbkf:stop
  Pauses running the program
  
• /function arcbkf:run_back
  Runs the program backward
  
• /function arcbkf:step
  Executes a single step of the program
  
• /function arcbkf:step_back
  Executes a single backward step of the program
  
• /scoreboard players set @s arcbkf_delay <number>
  Sets the delay between frames used when running the program to <number> ticks
  
• /scoreboard players set @s arcbkf_tick_steps <number>
  Sets the number of steps to be evaluated in a tick when running the program to <number>
  
• Shortcuts for setting evaluation speed:
  
  • /function arcbkf:speed_slower
    Delay 20 (1s), single-step
    
  • /function arcbkf:speed_slow
    Delay 10 (500ms), single-step
    
  • /function arcbkf:speed_medium
    Delay 5 (250ms), single-step
    
  • /function arcbkf:speed_fast
    Delay 1 (50ms), single-step
    
  • /function arcbkf:speed_super
    Delay 1, 30 steps per tick
    
  • /function arcbkf:speed_extreme
    Delay 1, 300 steps per tick

Example program

An example program, which takes a 3-bit binary number as input using mirrors and outputs the corresponding decimal digit, can be loaded from arcbkf:3_bit_decoder using a structure block (the structure has signs giving further instructions on using the program)

Links

• YouTube video
  
• GitHub