remove left recursion

rm_lr.js

var rm_lr = function(name, grammar) {
    var p_with = grammar[name].filter(function(x) { return x[0] == name; }),
        p_wo   = grammar[name].filter(function(x) { return x[0] != name; });

    grammar[name] = p_wo.concat(p_wo.map(function(wo) {
        return wo.concat([name + "'"]);
    }));

    grammar[name + "'"] = [['e']].concat(p_with.map(function(x) {
      return x.slice(1).concat([name + "'"]);
    }));
}