Back to non-naked constructor, @, preincrement, comprehension bracketing, idioms: calls, comprehensions, interpolations

examples/blocks.coffee

@@ -31,7 +31,7 @@ File.open = (path, mode, block) ->
 # Write.
 write = (location, data) ->
   path = new Pathname location
-  throw new Error "Location does not exist" unless fs.existsSync(location)
+  throw new Error "Location does not exist" unless fs.existsSync location
 
   File.open path, 'w', (file) ->
     return false if Digest.MD5.hexdigest(file.read()) is data.hash()

examples/code.coffee

@@ -13,7 +13,7 @@ run_loop = ->
   wait()
 
 # Objects:
-dense_object_literal = {one: 1, two: 2, three: 3}
+dense_object_literal = one: 1, two: 2, three: 3
 
 spaced_out_multiline_object =
   pi: 3.14159
@@ -56,7 +56,7 @@ race = ->
   run()
   walk()
   crawl()
-  if tired then return sleep()
+  return sleep() if tired
   race()
 
 # Conditional assignment:
@@ -64,7 +64,7 @@ good or= evil
 wine and= cheese
 
 # Nested property access and calls.
-((moon.turn(360))).shapes[3].move({x: 45, y: 30}).position['top'].offset('x')
+(moon.turn 360).shapes[3].move(x: 45, y: 30).position['top'].offset('x')
 
 a = b = c = 5
 
@@ -79,7 +79,7 @@ try
   dogs_and_cats_living_together()
   throw "up"
 catch error
-  print(error)
+  print error
 finally
   clean_up()
 
@@ -130,8 +130,8 @@ wednesday = -> eat_breakfast(); go_to_work(); eat_dinner()
 
 # Multiline strings with inner quotes.
 story = "Lorem ipsum dolor \"sit\" amet, consectetuer adipiscing elit,
-sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna
-aliquam erat volutpat. Ut wisi enim ad."
+         sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna
+         aliquam erat volutpat. Ut wisi enim ad."
 
 # Inheritance and calling super.
 class Animal

examples/computer_science/binary_search.coffee

@@ -22,4 +22,4 @@ binary_search = (items, value) ->
 console.log  2 is binary_search [10, 20, 30, 40, 50], 30
 console.log  4 is binary_search [-97, 35, 67, 88, 1200], 1200
 console.log  0 is binary_search [0, 45, 70], 0
-console.log(-1 is binary_search [0, 45, 70], 10)
+console.log -1 is binary_search [0, 45, 70], 10

examples/computer_science/bubble_sort.coffee

@@ -1,8 +1,8 @@
 # A bubble sort implementation, sorting the given array in-place.
 bubble_sort = (list) ->
   for i in [0...list.length]
-    for j in [0...list.length - i]
-      [list[j], list[j+1]] = [list[j+1], list[j]] if list[j] > list[j+1]
+    for j in [0...list.length - i] when list[j] > list[j + 1]
+      [list[j], list[j+1]] = [list[j + 1], list[j]]
   list
 
 

examples/computer_science/linked_list.coffee

@@ -1,8 +1,8 @@
 # "Classic" linked list implementation that doesn't keep track of its size.
 class LinkedList
 
-  ->
-    this._head = null # Pointer to the first item in the list.
+  constructor: ->
+    @_head = null # Pointer to the first item in the list.
 
 
   # Appends some data to the end of the list. This method traverses the existing
@@ -12,10 +12,10 @@ class LinkedList
     # Create a new node object to wrap the data.
     node = data: data, next: null
 
-    current = this._head or= node
+    current = @_head or= node
 
-    if this._head isnt node
-      (current = current.next) while current.next
+    if @_head isnt node
+      current = current.next while current.next
       current.next = node
 
     this
@@ -27,11 +27,11 @@ class LinkedList
     # Check for out-of-bounds values.
     return null if index < 0
 
-    current = this._head or null
+    current = @_head or null
     i = -1
 
     # Advance through the list.
-    (current = current.next) while current and index > (i += 1)
+    current = current.next while current and index > ++i
 
     # Return null if we've reached the end.
     current and current.data
@@ -43,16 +43,16 @@ class LinkedList
     # Check for out-of-bounds values.
     return null if index < 0
 
-    current = this._head or null
+    current = @_head or null
     i = -1
 
     # Special case: removing the first item.
     if index is 0
-      this._head = current.next
+      @_head = current.next
     else
 
       # Find the right location.
-      ([previous, current] = [current, current.next]) while index > (i += 1)
+      [previous, current] = [current, current.next] while index > ++i
 
       # Skip over the item to remove.
       previous.next = current.next
@@ -63,7 +63,7 @@ class LinkedList
 
   # Calculate the number of items in the list.
   size: ->
-    current = this._head
+    current = @_head
     count = 0
 
     while current
@@ -76,7 +76,7 @@ class LinkedList
   # Convert the list into an array.
   toArray: ->
     result  = []
-    current = this._head
+    current = @_head
 
     while current
       result.push current.data
@@ -86,7 +86,7 @@ class LinkedList
 
 
   # The string representation of the linked list.
-  toString: -> this.toArray().toString()
+  toString: -> @toArray().toString()
 
 
 # Tests.

examples/computer_science/luhn_algorithm.coffee

@@ -7,13 +7,13 @@ is_valid_identifier = (identifier) ->
   sum = 0
   alt = false
 
-  for i in [identifier.length - 1..0] by -1
+  for c in identifier by -1
 
     # Get the next digit.
-    num = parseInt identifier.charAt(i), 10
+    num = parseInt c, 10
 
     # If it's not a valid number, abort.
-    return false if isNaN(num)
+    return false if isNaN num
 
     # If it's an alternate number...
     if alt

examples/computer_science/merge_sort.coffee

@@ -3,13 +3,12 @@ merge_sort = (list) ->
 
   return list if list.length is 1
 
-  result  = []
   pivot   = Math.floor list.length / 2
   left    = merge_sort list.slice 0, pivot
   right   = merge_sort list.slice pivot
 
-  while left.length and right.length
-    result.push(if left[0] < right[0] then left.shift() else right.shift())
+  result = while left.length and right.length
+    if left[0] < right[0] then left.shift() else right.shift()
 
   result.concat(left).concat(right)
 

examples/poignant.coffee

@@ -1,8 +1,11 @@
 # Examples from the Poignant Guide.
+# These are examples of syntax differences between CoffeeScript and Ruby,
+# they won't run.
 
 # ['toast', 'cheese', 'wine'].each { |food| print food.capitalize }
 
-['toast', 'wine', 'cheese'].each (food) -> print food.capitalize()
+print food.capitalize() for food in ['toast', 'wine', 'cheese']
+
 
 
 
@@ -42,13 +45,10 @@ LotteryDraw =
   play: ->
     result  = LotteryTicket.new_random()
     winners = {}
-    this.tickets.each (buyer, ticket_list) ->
-      ticket_list.each (ticket) ->
-        score = ticket.score result
-        return if score is 0
-        winners[buyer] or= []
-        winners[buyer].push [ticket, score]
-    this.tickets = {}
+    for buyer, ticketList of @tickets
+      for ticket in ticketList when (score = ticket.score result) isnt 0
+        (winners[buyer] or= []).push [ticket, score]
+    @tickets = {}
     winners
 
 
@@ -64,7 +64,7 @@ LotteryDraw =
 
 WishScanner =
   scan_for_a_wish: ->
-    wish = this.read().detect (thought) -> thought.index('wish: ') is 0
+    wish = @read().detect (thought) -> thought.indexOf('wish: ') is 0
     wish.replace 'wish: ', ''
 
 
@@ -109,28 +109,28 @@ Creature =
 
   # This method applies a hit taken during a fight.
   hit: (damage) ->
-    p_up = Math.rand this.charisma
+    p_up = Math.rand @charisma
     if p_up % 9 is 7
-      this.life += p_up / 4
-      console.log "[" + this.name + " magick powers up " + p_up + "!]"
-    this.life -= damage
-    if this.life <= 0 then console.log "[" + this.name + " has died.]"
+      @life += p_up / 4
+      console.log "[#{@name} magick powers up #{p_up}!]"
+    @life -= damage
+    if @life <= 0 then console.log "[#{@name} has died.]"
 
   # This method takes one turn in a fight.
   fight: (enemy, weapon) ->
-    if this.life <= 0 then return console.log "[" + this.name + "is too dead to fight!]"
+    return console.log "[#{@name} is too dead to fight!]" if @life <= 0
 
     # Attack the opponent.
-    your_hit = Math.rand this.strength + weapon
-    console.log "[You hit with " + your_hit + "points of damage!]"
+    your_hit = Math.rand @strength + weapon
+    console.log "[You hit with #{your_hit}points of damage!]"
     enemy.hit your_hit
 
     # Retaliation.
     console.log enemy
     if enemy.life > 0
       enemy_hit = Math.rand enemy.strength + enemy.weapon
-      console.log "[Your enemy hit with " + enemy_hit + "points of damage!]"
-      this.hit enemy_hit
+      console.log "[Your enemy hit with #{enemy_hit}points of damage!]"
+      @hit enemy_hit
 
 
 
@@ -156,7 +156,7 @@ code_words.each (real, code) -> idea.replace(real, code)
 # Save the jibberish to a new file
 print "File encoded. Please enter a name for this idea: "
 idea_name = gets().strip()
-File.open "idea-" + idea_name + '.txt', 'w', (file) -> file.write idea
+File.open "idea-#{idea_name}.txt", 'w', (file) -> file.write idea
 
 
 
@@ -174,8 +174,8 @@ File.open "idea-" + idea_name + '.txt', 'w', (file) -> file.write idea
 
 wipe_mutterings_from = (sentence) ->
   throw new Error "cannot wipe mutterings" unless sentence.indexOf
-  while sentence.indexOf('(') >= 0
-    open     = sentence.indexOf('(') - 1
-    close    = sentence.indexOf(')') + 1
-    sentence = sentence.slice(0, open) + sentence.slice(close, sentence.length)
+  while '(' in sentence
+    open     = sentence.indexOf('(')
+    close    = sentence.indexOf(')')
+    sentence = "#{sentence[0...open]}#{sentence[close + 1..]}"
     sentence

examples/potion.coffee

@@ -45,7 +45,7 @@ foods[2]
 #   (key, ' is a ', val) join print.
 
 for key, val of {dog: 'canine', cat: 'feline', fox: 'vulpine'}
-  print key + ' is a ' + val
+  print "#{key} is a #{val}"
 
 
 # Person = class: /name, /age, /sex.
@@ -54,7 +54,7 @@ for key, val of {dog: 'canine', cat: 'feline', fox: 'vulpine'}
 
 class Person
   print: ->
-    print 'My name is ' + @name + '.'
+    print "My name is #{@name}."
 
 
 # p = Person ()
@@ -74,7 +74,7 @@ class Policeman extends Person
   (@rank) ->
 
   print: ->
-    print 'My name is ' + @name + " and I'm a " + @rank + '.'
+    print "My name is #{@name} and I'm a #{@rank}."
 
 print new Policeman 'Constable'
 
@@ -180,7 +180,7 @@ if 3.gender?
 #   session = url query ? at ('session').
 
 HomePage::get = (url) ->
-  session = url.query.session if url.query?
+  session = url.query?.session
 
 
 # BTree = class: /left, /right.

examples/web_server.coffee

@@ -7,6 +7,6 @@ server = http.createServer (req, res) ->
   res.write 'Hello, World!'
   res.end()
 
-server.listen 3000
+server.listen PORT = 3000
 
-console.log "Server running at http://localhost:3000/"
+console.log "Server running at http://localhost:#{PORT}/"