A naïve JavaScript implementation of a reverse polish calculator.

naïve-reverse-polish-calculator.js

var
  ReversePolish
;

ReversePolish = {};

(function (exports) {
  var
    operations
  ;

  operations = {
    "-": function (a, b) {
      return (a - b);
    },
    "+": function (a, b) {
      return (a + b);
    }
  };

  function evaluate(tokens) {
    var
      stack
    ;

    stack = [];

    tokens.forEach(function (token) {
      var
        argument_1,
        argument_2,
        number,
        operation,
        result
      ;

      if (token in operations) {
        if (operations.hasOwnProperty(token)) {
          argument_2 = stack.pop();
          argument_1 = stack.pop();
          operation = operations[token];
          result = operation(argument_1, argument_2);

          stack.push(result);
        }
      } else {
        number = parseInt(token, 10);

        stack.push(number);
      }
    });

    return stack.pop();
  }

  exports.evaluate = evaluate;
})(ReversePolish);

naïve-reverse-polish-calculator.min.js

var ReversePolish;ReversePolish={},function(a){function c(a){var c;return c=[],a.forEach(function(a){var d,e,f,g,h;a in b?b.hasOwnProperty(a)&&(e=c.pop(),d=c.pop(),g=b[a],h=g(d,e),c.push(h)):(f=parseInt(a,10),c.push(f))}),c.pop()}var b;b={"-":function(a,b){return a-b},"+":function(a,b){return a+b}},a.evaluate=c}(ReversePolish);