Zahradnice

fun with type-0 grammars (or something like that)

Requirements

• ascii
• 8 color terminal
• ncursesw (wide character ncurses)
• SDL2_mixer
• zlib

Build and run

make                      # or: make zahradnice-size, for the small binary
./zahradnice              # opens the main menu
./zahradnice programs/life.cfg --seed 42
make test                 # screen dumps, idle CPU, menu behaviour

In a menu: w/s choose, e runs, q goes back one level (and quits at the top). A menu re-opens on the entry you left through. SPACE pauses where a program wires it, F12 writes a screenshot, ESC always exits.

Programs

Access programs through the main menu (programs/index.cfg) or run directly:

• flowers (programs/flowers.cfg)
  • original intention
  • colorful terminal scenery inspired by Prune and Tree.Bonsai
• snake (programs/snake/)
  • take on the classic Snake game genre
• life (programs/life-setup.cfg)
  • asynchronous version of Conway's Game of Life
• sokoban (programs/sokoban/)
  • classic Sokoban puzzle game
• high noon (programs/highnoon.cfg)
  • fake ZX Spectrum shoot 'em up High Noon
• tetris (programs/tetris/)
  • just to compare readability and sizes with tinytetris
• zen garden (programs/zen.cfg)
  • meditative visual experience
• maze for two (programs/maze.cfg)
  • two-player maze game
• hex (programs/hex/)
  • hex-grid world to walk around
• primes (programs/primes/)
  • six ways to sieve, below
• evolution (experiments/)
  • the research programs: forest fire, an evolving forest, a heritable trait, a Manna sandpile, a contact process, a petri dish

Prime sieves

Six programs in programs/primes/, ordered by how far the divisor moves out of the rule set — from a comb per divisor written into the grammar, to a divisor that is nothing but the height of a band of rows, to two automata that carry no notion of divisibility at all. The last two are implementations of published constructions rather than inventions of this repository:

• 01-eratosthenes — a comb per divisor; magnitude is the screen column
• 02-bands — a divisor is a band of rows, so a wider terminal sieves further
• 03-counters — positional counters, one row per divisor, base as a parameter
• 04-packed — packed static counters; one record costs one rule application
• 05-fischer — P. C. Fischer, "Generation of Primes by a One-Dimensional Real-Time Iterative Array", JACM 12(3) (1965) 388–394. The verdict for n stands in column 3n.
• 06-umeo — H. Umeo, K. Miyamoto, Y. Abe, "Real-Time Prime Generators Implemented on Small-State Cellular Automata", in Automata, Universality, Computation, ECC vol. 12, Springer 2015, 341–352. Their Fig. 15.7, in eight states, one column per number.

Each file is generated by its tools/gen_primes*.py; edit the generator, not the .cfg.

Papers

paper/ holds five write-ups of experiments run inside this engine, on what a rewriting system has to pay for before anything in it can be inherited, kept, or lost.

What they can be trusted for is what they measured. Predictions were registered before each sweep and scored afterwards including the ones that failed — the last paper's scoreboard reads eighteen held, seven failed, two partial, and five of its named laws are the failures. Runs are seed-deterministic and replayed byte-for-byte against their event traces, and the whole arc required no change to the engine.

They are self-published, and designed and checked by one human–model pair, so read them as an instrument's log rather than as findings about biology — as the first paper puts it in its own limits section, reproducing known laws validates the instrument, not the science. Independent replication means running the committed scripts.

• Zahradnice: a Grammar Garden as an Experimental Substrate — what the substrate is, what it costs to ask it a question, and what it cannot model
• The Subtraction Ladder — what falls out when ingredients are removed one at a time
• Law Made of Matter — rules written in the same stuff they act on
• Machinery That Earns the Channels — what inheritance costs to acquire
• What Someone Can Keep — selection sees only what someone can keep

The repository and its papers are archived at 10.5281/zenodo.22059784; see CITATION.cff.

Grammar

See GRAMMAR.md for the language reference and a programming intro, GRAMMAR-pitfalls.md for the quirks that bite in practice, HEADLESS.md for driving the engine without a terminal, and TRACING.md for instrumentation.

License

Everything here is dedicated to the public domain under CC0 1.0 — no conditions. One non-binding request from the authors: this garden was grown as a commons; if it proves useful, tend it in that spirit. (Per the repository's own night-10 result, a rule could not enforce this anyway — what persists is decided by what the commons feeds.)