ariel.js

function ariel_eval(src_ari, reader, writer) {
  var src =
    '(function(reader, writer) {' +
    '  var stack = [];' +
    '  var sp = 0;';

  var INSNS = [
    { re: /^\s*あり\s*あり\s*あり/,
      js: '++sp;' },
    { re: /^\s*あり\s*あり\s*える/,
      js: '--sp;' },
    { re: /^\s*あり\s*える\s*あり/,
      js: 'stack[sp] = (stack[sp] === undefined ? 0 : stack[sp]) + 1;' },
    { re: /^\s*あり\s*える\s*える/,
      js: 'stack[sp] = (stack[sp] === undefined ? 0 : stack[sp]) - 1;' },
    { re: /^\s*える\s*あり\s*あり/,
      js: 'writer(String.fromCharCode(stack[sp]));' },
    { re: /^\s*える\s*あり\s*える/,
      js: 'stack[sp] = reader().charCodeAt(0);' },
    { re: /^\s*える\s*える\s*あり/,
      js: 'while(stack[sp] !== 0) {' },
    { re: /^\s*える\s*える\s*える/,
      js: '}' }
  ];

  for (var matched = true; matched;) {
    matched = false;

    for (var i = 0; INSNS[i]; ++i) {
      var insn = INSNS[i];
      var m = insn.re.exec(src_ari);
      if (m) {
        src += insn.js;
        src_ari = src_ari.substr(m[0].length);
        matched = true;
        continue;
      }
    }
  }

  src += '})';
  console.log(src);
  eval(src)(reader, writer);
}

function ariel_console(el) {
  var console = document.createElement('div');
  var input = document.createElement('textarea');
  input.rows = 8;
  input.cols = 40;
  var src = document.createElement('textarea');
  src.rows = 24;
  src.cols = 80;
  var eval_btn = document.createElement('input');
  eval_btn.type = 'button';
  eval_btn.value = 'EVAL';

  el.appendChild(console);
  el.appendChild(input);
  el.appendChild(src);
  el.appendChild(eval_btn);

  eval_btn.addEventListener('click', function() {
    var ip = 0;
    ariel_eval(
      src.value,
      function() { return input.value[ip++] },
      function(c) { console.innerHTML += c }
    );
  }, false);
}