The document discusses CoffeeScript, a programming language that compiles to JavaScript. It provides examples of CoffeeScript syntax for functions, conditionals, loops, classes, and other constructs. It explains how CoffeeScript aims to have less syntactic noise than JavaScript while remaining true to the underlying JavaScript semantics through compilation.

1. Damn Fine
CoffeeScript

2. Focus
Language

3. Some Kind of Holy
Python
Ruby
JavaScrip t

4. Raw
var render = function (width, height, draw, filePath)
{
var canvas = new Canvas(width, height),
ctx = canvas.getContext('2d');
draw.call(ctx);
var out = fs.createWriteStream(filePath),
stream = canvas.createPNGStream();
stream.on('data', function(chunk) {
out.write(chunk);
});
stream.on('end', function() {
console.log("Created: " + filePath);
});
};

5. Brewed
render = (width, height, draw, filePath) ->
canvas = new Canvas(width, height)
draw.call canvas.getContext '2d'
out = fs.createWriteStream filePath
stream = canvas.createPNGStream()
stream.on 'data', (chunk) ->
out.write chunk
stream.on 'end', ->
console.log "Created: #{filePath}"

6. Basically
● function is () ->
● local variables
● indentation
● omittable parentheses

7. True To JavaScript
The golden rule of CoffeeScript is: "It's just
JavaScript"

8. Less Syntactic Noise
stream.on('end', function() {
console.log("Created: " +
filePath);
});

9. stream.on 'end', ->
console.log "Created: #{filePath}"

10. My perspective
Node
A platform: JS machine + CommonJS stdlib

11. Runtimes

12. It's just
Coffee In Coffee

13. Browser
Just JS (generated)

14. Convert & Eval...
<script src="/extras/coffee-script.js"></script>
<script type="text/coffeescript">
# coffee time
</script>

15. Node
$ npm install coffee-script

16. REPL
$ coffee

17. 101
# Assignment:
number = 42
opposite = true

18. Conditions
if happy and knowsIt
clapsHands()
chaChaCha()
else
showIt()
date = if friday then sue else jill
options or= defaults
number = -42 if opposite

19. Functions
square = (x) -> x * x
cube = (x) -> square(x) * x
fill = (container, liquid="coffee") ->
"Filling the #{container} with #{liquid}..."
noop = ->

20. In JQuery
$('span').each ->
it = $(this)
if it.is('.style-1, .style-20') or
not it.attr('class')
it.replaceWith(it.html())

21. Data
# Arrays:
list = [1, 2, 3, 4, 5]
# Objects:
math =
root: Math.sqrt
square: square
cube: (x) -> x * square x

22. modes = {ready: yes, balance: off}
bitlist = [
1, 0, 1
0, 0, 1
1, 1, 0
]

23. How True To JavaScript?

24. Compile
$ coffee -c some.coffee
# or just print out
$ coffee -p some.coffee

25. number = 42
opposite = true
number = -42 if opposite
list = [1, 2, 3, 4, 5]
math =
root: Math.sqrt
square: square
cube: (x) -> x * square x

26. var list, math, number, opposite;
number = 42;
opposite = true;
if (opposite) {
number = -42;
}
list = [1, 2, 3, 4, 5];
math = {
root: Math.sqrt,
square: square,
cube: function(x) {
return x * square(x);
}
};

27. Lexical Scopes & Safety
outer = 1
changeNumbers = ->
inner = -1
outer = 10
inner = changeNumbers()

28. var changeNumbers, inner, outer;
outer = 1;
changeNumbers = function() {
var inner;
inner = -1;
return outer = 10;
};
inner = changeNumbers();

29. Syntactic
Thin Coat of Sugar
And Some Boilerplate

30. Sugar++
# Splats:
race = (winner, runners...) ->
print winner, runners
# Existence:
alert "I knew it!" if elvis?

31. var race;
var __slice = Array.prototype.slice;
var 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!");
}

32. Expressions, Implicitness, Return

33. Unpacking
[first, second] = [1, 2, 3, 4]
_ref = [1, 2, 3], first = _ref[0], second = _ref[1];

34. {puts, inspect} = require 'util'
_ref2 = require('util'), puts = _ref2.puts, inspect =
_ref2.inspect;

35. Comprehensions!
cubes = (math.cube num for num in list)

36. var cubes;
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;
})();

37. Comprehensive
yearsOld = max: 10, ida: 9, tim: 11
ages = for child, age of yearsOld
child + " is " + age

38. Closing Over Loops
for filename in list
do (filename) ->
fs.readFile filename, (err, contents) ->
compile filename, contents.toString()

39. Operator Names
CoffeeScript JavaScript
is, isnt ===, !==
and, or, not &&, ||, !
true, yes, on true
false, no, off false
in, of in, N/A
@, this this
:: prototype

40. Different Kinds of Else
● unless
● a?
●a ? b
● a ?= b
● a?.b

41. Classes
class Animal
constructor: (@name) ->
move: (meters) ->
alert @name + " moved " + meters + "m."
class Snake extends Animal
move: ->
alert "Slithering..."
super 5
class Horse extends Animal
move: ->
alert "Galloping..."
super 45
sam = new Snake "Sammy the Python"
tom = new Horse "Tommy the Palomino"
sam.move()
tom.move()

42. var Animal, Horse, Snake, sam, tom;
var __hasProp = Object.prototype.hasOwnProperty, __extends =
function(child, parent) {
for (var key in parent) { if (__hasProp.call(parent, key))
child[key] = parent[key]; }
function ctor() { this.constructor = child; }
ctor.prototype = parent.prototype;
child.prototype = new ctor;
child.__super__ = parent.prototype;
return child;
};

43. Animal = (function() {
function Animal(name) {
this.name = name;
}
Animal.prototype.move = function(meters) {
return alert(this.name + " moved " + meters + "m.");
};
return Animal;
})();

44. Snake = (function() {
__extends(Snake, Animal);
function Snake() {
Snake.__super__.constructor.apply(this, arguments);
}
Snake.prototype.move = function() {
alert("Slithering...");
return Snake.__super__.move.call(this, 5);
};
return Snake;
})();

45. Binding => This
Account = (customer, cart) ->
@customer = customer
@cart = cart
$('.shopping_cart').bind 'click', (event) =>
@customer.purchase @cart

46. var Account;
var __bind = function(fn, me){ return function(){ return
fn.apply(me, arguments); }; };
Account = function(customer, cart) {
this.customer = customer;
this.cart = cart;
return $('.shopping_cart').bind('click', __bind(function(event)
{
return this.customer.purchase(this.cart);
}, this));
};

47. And more...

48. ● Literals: Functions, Objects and Arrays
● If, Else, Unless, and Conditional Assignment

49. ● Splats...
● Array Slicing and Splicing
● Loops and Comprehensions
● Destructuring Assignment
● Everything is an Expression

50. ● Operators and Aliases
● Lexical Scoping and Variable Safety
● Classes, Inheritance, and Super
● Function Binding

51. ● Switch and Try/Catch
● Chained Comparisons
● String Interpolation, Heredocs, and Block
Comments
● Extended Regular Expressions
● Embedded JavaScript

52. Future/Now

53. Coding in Coffee
sameness?
seeing clearly..
transparencies..
choices...

54. Paths Ahead?
Harmony...

55. Tinkering Fun!
Node goodies: Zombie.js, Canvas, ...

56. Developing a
CommonJS Lib

57. $ npm link .
$ coffee --watch src
$ cake

58. Cakefile
{spawn, exec} = require 'child_process'
SRC = 'js/src'
LIB = 'js/lib'
task 'build', "compile coffee to js", -> build onErrorExit
task 'watch', "continously compile coffee to js", ->
cmd = spawn "coffee", ["-cw", "-o", LIB, SRC]
cmd.stdout.on "data", (data)-> process.stdout.write data
cmd.on "error", onErrorExit
build = (cb)->
console.log "Coffee compiling..."
exec "rm -rf #{LIB} && coffee -c -l -b -o #{LIB} #{SRC}",
(err, out)-> cb err
onErrorExit = (err)->
if err
process.stdout.write "#{err.stack}n"
process.exit -1

59. Thanks!

60. Image Tributes (CC)
"Black as midnight on a moonless night."
Knight of the Holy Grail
Reflecting on a Sunday afternoon
In The Red Room
Fall down mountains, just don't fall on me
Midnight Black
Orrery Steam Punk Assemblage by urbandon
Steampunk Time Contraption