turing-machine-simulator

Stateless, functional turing machine simulator.

API subject to massive changes.

Usage

You will need to define a definition object to construct a Turing Machine. The TM exposes accepts and rejects methods, which return true or false on string inputs.

Here's an example for the language consisting of strings that contain the substring 11 over the alphabet { 0, 1 }:

const { TuringMachine } = require("./");
const { NULL, REJECT_STATE, Directions } = require("./constants");

const states = {
  q1: Symbol("q1"),
  q2: Symbol("q2"),
  q3: Symbol("q3"),
};

const transitionTable = {
  [states.q1]: {
    0: [ states.q1, Directions.RIGHT ],
    1: [ states.q2, Directions.RIGHT ],
    [NULL]: [ REJECT_STATE, Directions.RIGHT ],
  },
  [states.q2]: {
    0: [ states.q1, Directions.RIGHT ],
    1: [ states.q3, Directions.RIGHT ],
    [NULL]: [ REJECT_STATE, Directions.RIGHT ],
  },
  [states.q3]: {
    0: [ states.q1, Directions.RIGHT ],
    1: [ states.q3, Directions.RIGHT ],
    [NULL]: [ REJECT_STATE, Directions.RIGHT ],
  },
};

const defn = {
  transitionFn: TuringMachine.makeTransitionFn(transitionTable),
  startState: states.q1,
  acceptState: states.q3,
  states,
};

const tm = new TuringMachine(defn);
tm.accepts("11") // true

There are a few more examples in index.test.js.