Is this a validated response about the last minutes from the video of Doug Crawford at mjg.in? http://frontendmasters.com/courses/javascript-the-good-parts/douglas-crockfords-function-challenges/

gistfile1.txt

 var add = function (add){ return add};
 var mul = function (mul){ return mul};

 var op = add || mul;

 

    var applyf = function(op){
        if ( op === add)
            return function(x){
                return function(y){
                    return x+y;
              }	
            };
        else if ( op === mul)
            return function(x){
                return function(y){
                    return x*y;
                }
            };
    }

addf = applyf(add);

alert ( addf(3)(4) );

alert ( applyf(mul)(5)(6) );

Just some basic js stuff!

Write a function that takes a binary function and makes it callable with two invocations

//

addf = applyf(add);

alert ( addf(3)(4) ); // 7

alert ( applyf(mul)(5)(6) ); // 30