functional js calculator

compose.js

var one = value(1);
var two = value(2);
var three = value(3);
var four = value(4);

// (1 + 2) * 3 - 4 == 5
var added = add(one, two)
var multiplied = multiply(added, three)
var resultFunc = subtract(multiplied, four);

// the result is the same. 
// it's been composed the same, functionally
// it was just put together with more variables in the mix
var result = resultFunc();
consol.log(result); // => 5

funcalc.js

// A raw value, represented as a function
var value = function(val){
  return function(){
    return val;
  }
}

// A function to add two functions together
var add = function(x, y){
  return function(){
   return x() + y();
  }
}

// A function to subtract one function from another
var subtract = function(x, y){
  return function(){
    return x() - y();
  }
}

// A function to multiply two functions
var multiply = function(x, y){
  return function(){
    return x() * y();
  }
}

prototypal.js

/**
 Prototypal
 from Oscar Godson: http://jsbin.com/atopek/edit#javascript
*/

var Calc = function(){
  this.sum = 0; //could be a param
  return this;
}

Calc.prototype.add = function(x){
  this.sum = this.sum + x;
  return this;
}

Calc.prototype.multiply = function(x){
  this.sum = this.sum * x
  return this;
}
  
Calc.prototype.subtract = function(x){
  this.sum = this.sum - x;
  return this
}

Calc.prototype.result = function(){
  return this.sum;
}

console.log(new Calc().add(1).add(2).multiply(3).subtract(4).result())

sample.js

var one = value(1);
var two = value(2);
var three = value(3);
var four = value(4);

// (1 + 2) * 3 - 4 == 5
var resultFunc = subtract(multiply(add(one, two), three), four);

// but it's still a function right now, so evaluate it
var result = resultFunc();
consol.log(result); // => 5