2012/05/20 19:16:35 | (82.253.245.161) 
{h1 turing}
{p {a {@ href:https://gist.github.com/1400509;} A turing machine in 79 bytes of javascript.}}

{pre {@ id:code; }°°
// added some curly braces for readability
var tm = function(
  a, // {Object} program @see test.html for details
  b, // {Number[]} tape
  c, // {String} end state
  d, // {String} start state
  e  // [{Number} = 0] caret position
) {

while(
  d < c // while ! eof program
) {
    /* 'e |= 0' - if e is undefined - reset to 0 else leave as is */
    with (/* q = */a[d][b[e |= 0] || "B"]) { 
      // push current program statement aka "q" to the top of current scope
      b[e] = w, // change symbol under caret, w is the item of "q"
      e += m,   // move caret by ..., m is the item of "q"
      d = n;    // jump to next state, n is the item of "q"
    }
}
return b;
}
  var program = {
 "q0": {"1": {"w": "B", "m": 1, "n": "q1"}
       },
 "q1": {"1": {"w": "1", "m": 1, "n": "q1"},
        "0": {"w": "0", "m": 1, "n": "q2"},
        "B": {"w": "0", "m": 1, "n": "q2"}
       },
 "q2": {"1": {"w": "1", "m": 1, "n": "q2"},
        "B": {"w": "1", "m": -1, "n": "q3"}
       },
 "q3": {"1": {"w": "1", "m": -1, "n": "q3"},
        "0": {"w": "0", "m": -1, "n": "q3"},
        "B": {"w": "1", "m": 1, "n": "q4"}
       },
 "q4": {"1": {"w": "B", "m": 1, "n": "q1"},
        "0": {"w": "0", "m": 1, "n": "q5"}
       }
};

  var tape = [1,1,1];
  
  $("ret").innerHTML = tm(program, tape, "q5", "q0", 0);

°°}

{submit {@ code:code; value:go; }}
{div {@ id:ret;} ???}