cellular

A cellular automaton library and command-line simulator written in MoonBit.

cellular provides two families of cellular automata:

• Life-like automata (2D) — configurable birth/survival rules using the standard B/S notation (e.g. Conway's Game of Life is B3/S23).
• Elementary cellular automata (1D) — the 256 Wolfram rules (0–255), including Rule 30, Rule 90, and Rule 110.

The core is pure functions over plain Bool arrays, so it is trivially testable and runs on the native, wasm, and wasm-gc targets.

Install

moon add sssssurf/cellular

Library usage

let rule = @cellular.conway()

// A glider: a spaceship that travels diagonally.
let mut grid = @cellular.glider()

for _ in 0..<4 {
  grid = @cellular.life_step(rule, grid, true) // toroidal edges
}

println(@cellular.render_grid(grid))

Custom life-like rules via B/S notation:

let highlife = @cellular.parse_life_rule("B36/S23").unwrap()
let grid = @cellular.life_step(highlife, @cellular.r_pentomino(), false)

1D elementary cellular automata:

let state : Array[Bool] = Array::make(41, false)
state[20] = true

for row in @cellular.eca_run(30, state, 16, false) {
  println(@cellular.render_eca(row)) // Rule 30 -> Sierpinski-like triangle
}

API overview

// Grid helpers
let g = @cellular.Grid::new(20, 20)
let g = @cellular.Grid::from_string(".#.\n###\n.#.").unwrap()
let g = @cellular.Grid::random(20, 20, 0.3)
let copy = g.copy()
let d : Double = g.density()          // fraction of live cells

// Stepping and analysis
let next = @cellular.life_step(rule, g, true)
let history : Array[Grid] = @cellular.life_run(rule, g, 10, true)
let pop : Array[Int] = @cellular.population_curve(rule, g, 10, true)

// Period detection (None if no repeat within the limit)
let period = @cellular.find_period(rule, g, 100, true)

@cellular.rule_descriptions() lists every built-in rule with its B/S notation.

Command line

Run the simulator without writing code:

# Conway's Game of Life, glider pattern, 10 generations
moon run cmd/main -- life B3/S23 10 glider

# Rule 30 (1D), width 41, 16 generations
moon run cmd/main -- eca 30 41 16

# List available patterns
moon run cmd/main -- patterns

# Random initial state, Conway's rule, 20x10 grid, 5 generations
moon run cmd/main -- random B3/S23 20 10 5

# Show every built-in rule and pattern
moon run cmd/main -- info

Rules and patterns

Command	Rule	Meaning
life B3/S23	Conway's Game of Life	the classic rule
life B36/S23	HighLife	adds a replicator
life B2/S	Seeds	every cell dies, explosive growth
life B3678/S34678	Day & Night	symmetric under on/off inversion
eca 30	Rule 30	chaotic, used as a PRNG
eca 90	Rule 90	Sierpinski triangle
eca 110	Rule 110	Turing-complete

Built-in patterns: block, blinker, toad, beacon, glider, r-pentomino, beehive, tub.

Additional life-like rules are also available as functions: replicator, life_without_death, maze, anneal, diamoeba, and coral.

Development

moon test          # run the test suite
moon build         # compile
moon run cmd/main -- help

License

Apache-2.0