Geeking out on CoffeeScript

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I’m gonna geek out today and share to people something that really caught my attention. A magical programming language called CoffeeScript.
Interesting name. So what is CoffeeScript? Well the source code looks like Python, but when you compile the source code it becomes JavaScript! So for example:

I have a simple popup alert that says “hello coffeescript”, then when you hit ok it prints the number 42:

alert "Hello CoffeeScript!"
number = 42
alert number

compile this and you get this:

var number;
alert("Hello CoffeeScript!");
number = 42;
alert(number);

For something a little bit more complex it would look like this:

# Assignment:
number   = 42
opposite = true

# Conditions:
number = -42 if opposite

# Functions:
square = (x) -> x * x

# Arrays:
list = [1, 2, 3, 4, 5]

# Objects:
math =
  root:   Math.sqrt
  square: square
  cube:   (x) -> x * square x

# Splats:
race = (winner, runners...) ->
  print winner, runners

# Existence:
alert "I knew it!" if elvis?

# Array comprehensions:
cubes = (math.cube num for num in list)

compile this, the source now becomes this:

var cubes, list, math, num, number, opposite, race, square,
  slice = [].slice;

number = 42;

opposite = true;

if (opposite) {
  number = -42;
}

square = function(x) {
  return x * x;
};

list = [1, 2, 3, 4, 5];

math = {
  root: Math.sqrt,
  square: square,
  cube: function(x) {
    return x * square(x);
  }
};

race = function() {
  var runners, winner;
  winner = arguments[0], runners = 2 <= arguments.length ? slice.call(arguments, 1) : [];
  return print(winner, runners);
};

if (typeof elvis !== "undefined" && elvis !== null) {
  alert("I knew it!");
}

cubes = (function() {
  var i, len, results;
  results = [];
  for (i = 0, len = list.length; i < len; i++) {
    num = list[i];
    results.push(math.cube(num));
  }
  return results;
})();

Excellent fun stuff!
For someone like me who, doesn’t really like JavaScript and can’t be bothered to learn it to write a small app as an odd job, this language is perfect

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