Merge branch 'master' of github.com:coffeescript-cookbook/coffeescript-cookbook.github.com

Author: thirdtruck

authors.textile

@@ -14,6 +14,7 @@ _The following people are totally rad and awesome because they have contributed
 * Sebastian Slomski [email protected]_
 * Aaron Weinberger [email protected]_
 * James C. Holder [email protected]_
+* Jason Giedymin [email protected]_
 * ...You! What are you waiting for? Check out the <a href="/contributing">contributing</a> section and get cracking!
 
 

chapters/arrays/reducing-arrays.textile

@@ -0,0 +1,43 @@
+---
+layout: recipe
+title: Reducing Arrays
+chapter: Arrays
+---
+
+h2. Problem
+
+You have an array of objects and want to reduce them to a value, similar to Ruby's <code>reduce()</code> and <code>reduceRight()</code>.
+
+h2. Solution
+
+You can simply use Array's <code>reduce()</code> and <code>reduceRight()</code> methods along with an anonoymous function, keeping the code clean and readable. The reduction may be something simple such as using the <code>+</code> operator with numbers or strings.
+
+{% highlight coffeescript %}
+[1,2,3,4].reduce (x,y) -> x + y
+# => 10
+{% endhighlight %}
+
+{% highlight coffeescript %}
+["words", "of", "bunch", "A"].reduceRight (x, y) -> x + " " + y
+# => 'A bunch of words'
+{% endhighlight %}
+
+Or it may be something more complex such as aggregating elements from a list into a combined object.
+
+{% highlight coffeescript %}
+people =
+    { name: '', age: 10 }
+    { name: '', age: 16 }
+    { name: '', age: 17 }
+
+people.reduce (x, y) ->
+    x[y.name]= y.age
+    x
+, {}
+# => { alec: 10, bert: 16, chad: 17 }
+{% endhighlight %}
+
+h2. Discussion
+
+Javascript introduced <code>reduce</code> and <code>reduceRight</code> in version 1.8. Coffeescript provides a natural and simple way to express anonymous functions. Both go together cleanly in the problem of merging a collection's items into a combined result.
+

chapters/design_patterns/singleton.textile

@@ -0,0 +1,66 @@
+---
+layout: recipe
+title: Singleton Pattern
+chapter: Design Patterns
+---
+
+h2. Problem
+
+Many times you only want one, and only one, instance of a class. For example, you may only need one class that creates server resources and you want to ensure that the one object can control those resources. Beware, however, because the singleton pattern can be easily abused to mimic unwanted global variables.
+
+h2. Solution
+
+The publically available class only contains the method to get the one true instance. The instance is kept within the closure of that public object and is always returned
+
+The actual definition of the singleton class follows.
+
+Note that I am using the idiomatic module export feature to emphasize the publically accessible portion of the module. Remember coffeescript wraps all files in a function block to protect the global namespace
+
+{% highlight coffeescript %}
+root = exports ? this # http://stackoverflow.com/questions/4214731/coffeescript-global-variables
+
+# The publically accessible Singleton fetcher
+class root.Singleton
+  _instance = undefined # Must be declared here to force the closure on the class
+  @get: (args) -> # Must be a static method
+    _instance ?= new _Singleton args
+
+# The actual Singleton class
+class _Singleton
+  constructor: (@args) ->
+
+  echo: ->
+    @args
+
+a = root.Singleton.get 'Hello A'
+a.echo()
+# => 'Hello A'
+
+b = root.Singleton.get 'Hello B'
+a.echo()
+# => 'Hello A'
+
+b.echo()
+# => 'Hello A'
+
+root.Singleton._instance 
+# => undefined
+
+root.Singleton._instance = 'foo' 
+
+root.Singleton._instance 
+# => 'foo'
+
+c = root.Singleton.get 'Hello C'
+c.foo() 
+# => 'Hello A'
+
+a.foo() 
+# => 'Hello A'
+{% endhighlight %}
+
+h2. Discussion
+
+See in the above example how all instances are outputting from the same instance of the Singleton class
+
+Note how incredibly simple coffeescript makes this design pattern. For reference and discussion on nice javascript implementations, check out http://addyosmani.com/resources/essentialjsdesignpatterns/book/

chapters/jquery/plugin.textile

@@ -0,0 +1,62 @@
+---
+layout: recipe
+title: Create a jQuery plugin
+chapter: jQuery
+---
+
+h2. Problem
+
+You'd like to create jQuery plugin using CoffeeScript
+
+h2. Solution
+
+{% highlight coffeescript %}
+# Reference jQuery
+$ = jQuery
+
+# Adds plugin object to jQuery
+$.fn.extend
+  # Change pluginName to your plugin's name.
+  pluginName: (options) ->
+    # Default settings
+    settings =
+      option1: true
+      option2: false
+      debug: false
+      
+    # Merge default settings with options.
+    settings = $.extend settings, options
+    
+    # Simple logger.
+    log = (msg) ->
+      console?.log msg if settings.debug
+    
+    # _Insert magic here._
+    return @each ()->
+      log "Preparing magic show."
+      # You can use your settings in here now.
+      log "Option 1 value: #{settings.option1}"
+{% endhighlight %}
+
+h2. Discussion
+
+h3. Usage
+
+Here are a couple of examples of how to use your new plugin.
+
+h4. JavaScript
+
+{% highlight javascript %}
+$("body").pluginName({
+  debug: true
+};
+
+{% endhighlight %}
+
+h4. CoffeeScript:
+
+{% highlight coffeescript %}
+$("body").pluginName
+  debug: true
+
+{% endhighlight %}

chapters/math/fast-fibonacci.textile

@@ -0,0 +1,103 @@
+---
+layout: recipe
+title: Faster Fibonacci algorithm
+chapter: Math
+---
+
+h2. Problem
+
+You would like to calculate a number N in the Fibonacci sequence but want
+to do it quickly.
+
+h2. Solution
+
+The following solution (which can still be improved on) was originally
+talked about on Robin Houston's blog.
+
+Here are a few links talking about the algorithm and ways to improve it:
+# <a href="http://bosker.wordpress.com/2011/04/29/the-worst-algorithm-in-the-world/">http://bosker.wordpress.com/2011/04/29/the-worst-algorithm-in-the-world/</a>
+# <a href="http://www.math.rutgers.edu/~erowland/fibonacci.html">http://www.math.rutgers.edu/~erowland/fibonacci.html</a>
+# <a href="http://jsfromhell.com/classes/bignumber">http://jsfromhell.com/classes/bignumber</a>
+# <a href="http://www.math.rutgers.edu/~erowland/fibonacci.html">http://www.math.rutgers.edu/~erowland/fibonacci.html</a>
+# <a href="http://bigintegers.blogspot.com/2010/11/square-division-power-square-root.html">http://bigintegers.blogspot.com/2010/11/square-division-power-square-root.html</a>
+# <a href="http://bugs.python.org/issue3451">http://bugs.python.org/issue3451</a>
+
+This code is in gist form here:
+<a href="https://gist.github.com/1032685">https://gist.github.com/1032685</a>
+
+{% highlight coffeescript %}
+### 
+Author: Jason Giedymin <jasong _a_t_ apache -dot- org>
+        http://www.jasongiedymin.com
+        https://github.com/JasonGiedymin
+
+This CoffeeScript Javascript Fast Fibonacci code is 
+based on the python code from Robin Houston's blog.
+See below links.
+
+A few things I want to introduce in time are implementions of 
+Newtonian, Burnikel / Ziegler, and Binet's algorithms on top
+of a Big Number framework.
+
+Todo: 
+- https://github.com/substack/node-bigint
+- BZ and Newton mods.
+- Timing
+
+
+###
+
+MAXIMUM_JS_FIB_N = 1476
+
+fib_bits = (n) ->
+	#Represent an integer as an array of binary digits.
+
+	bits = []
+	while n > 0
+    	[n, bit] = divmodBasic(n, 2)
+    	bits.push(bit)
+
+  	bits.reverse()
+  	return bits
+
+fibFast = (n) ->
+	#Fast Fibonacci
+
+	if n < 0
+		console.log "Choose an number >= 0"
+		return
+
+	[a, b, c] = [1, 0, 1]
+
+	for bit in fib_bits(n)
+	    if bit
+	    	[a, b] = [(a+c)*b, b*b + c*c]
+	    else
+	    	[a, b] = [a*a + b*b, (a+c)*b]
+
+	    c = a + b
+	  	return b
+
+divmodNewton = (x, y) ->
+	throw new Error "Method not yet implemented yet."
+
+divmodBZ = () ->
+	throw new Error "Method not yet implemented yet."
+
+divmodBasic = (x, y) ->
+	###
+	Absolutely nothing special here. Maybe later versions will be Newtonian or
+	Burnikel / Ziegler _if_ possible...
+	###
+
+	return [(q = Math.floor(x/y)), (r = if x < y then x else x % y)]
+
+start = (new Date).getTime();
+calc_value = fibFast(MAXIMUM_JS_FIB_N)
+diff = (new Date).getTime() - start;
+console.log("[#{calc_value}] took #{diff} ms.")
+{% endhighlight %}
+
+h2. Discussion
+
+Questions?

wanted-recipes.textile

@@ -26,12 +26,6 @@ h2. Strings
 
 h2. Arrays
 
-* Reducing arrays to values (ruby inject) with reduce # [1..10].reduce (a,b) -> a+b # 55
-* Reducing arrays in reverse order # JS reduceRight 
-{% highlight coffeescript %}
-["example", "contrived ", "pretty ", "a ", "is ", "here "].reduceRight (x,y) -> x+y
-# => 'here is a pretty contrived example'
-{% endhighlight %}
 * Testing every element in an array
 {% highlight coffeescript %}
 evens = (x for x in [0..10] by 2)