Editorial changes and clarifications.

Author: thirdtruck

chapters/design_patterns/builder.textile

@@ -6,11 +6,13 @@ chapter: Design Patterns
 
 h2. Problem
 
-You need to prepare a complicated, multi-part object, more than once or with varying configurations.
+You need to prepare a complicated, multi-part object, but you expect to do it more than once or with varying configurations.
 
 h2. Solution
 
-Create a Builder to encapsulate the production process.
+Create a Builder to encapsulate the object production process.
+
+The <a href="http://todotxt.com">Todo.txt</a> format provides an advanced but still plain-text method for maintaining lists of to-do items.  Typing out each item by hand would provide exhausting and error-prone, however, so a TodoTxtBuilder class could save us the trouble:
 
 {% highlight coffeescript %}
 TodoTxtBuilder = (defaultParameters={ }) ->
@@ -24,9 +26,9 @@ TodoTxtBuilder = (defaultParameters={ }) ->
         projects = this.projects.concat(parameters.projects or [ ])
         priorityLevel = parameters.priority or this.priority
         createdAt = [date.getFullYear(), date.getMonth()+1, date.getDate()].join("-")
-        contextNames = ("@" + context for context in contexts).join(" ")
-        projectNames = ("+" + project for project in projects).join(" ")
-        priority = if priorityLevel then "(" + priorityLevel + ")" else ""
+        contextNames = ("@#{context}" for context in contexts).join(" ")
+        projectNames = ("+#{project}" for project in projects).join(" ")
+        priority = if priorityLevel then "(#{priorityLevel})" else ""
         [priority, createdAt, description, contextNames, projectNames].reduce (whole, part) ->
             if part then (whole and whole + " ") + part else whole
 
@@ -38,19 +40,19 @@ builder.newTodo "Wash laundry"
 
 workBuilder = new TodoTxtBuilder(date: "10/13/2011", contexts: ["work"])
 
-workBuilder.newTodo "Show the new design pattern to Sean", contexts: ["desk", "xpSession"]
+workBuilder.newTodo "Show the new design pattern to Lucy", contexts: ["desk", "xpSession"]
 
-# => '2011-10-13 Show the new design pattern to Sean @work @desk @xpSession'
+# => '2011-10-13 Show the new design pattern to Lucy @work @desk @xpSession'
 
-workBuilder.newTodo "Remind Lucy about the failing unit tests", contexts: ["meeting"], projects: ["compilerRefactor"], priority: 'A'
+workBuilder.newTodo "Remind Sean about the failing unit tests", contexts: ["meeting"], projects: ["compilerRefactor"], priority: 'A'
 
-# => '(A) 2011-10-13 Remind Lucy about the failing unit tests @work @meeting +compilerRefactor'
+# => '(A) 2011-10-13 Remind Sean about the failing unit tests @work @meeting +compilerRefactor'
 
 {% endhighlight %}
 
 h2. Discussion
 
-Based on the <a href="http://todotxt.com">Todo.txt</a> format, the TodoTxtBuilder class takes care of all the heavy lifting of text generation and lets the programmer focus on the unique elements of each todo item.  A command line tool tool or GUI could plug into this code and retain support for later, more advanced versions of the format with ease.
+The TodoTxtBuilder class takes care of all the heavy lifting of text generation and lets the programmer focus on the unique elements of each to-do item.  Additionally, a command line tool or GUI could plug into this code and still retain support for later, more advanced versions of the format with ease.
 
 h3. Pre-Construction
 
@@ -82,3 +84,7 @@ builder.newTodo "Fill gas tank"
 # => '2011-10-13 Fill gas tank +summerVacation'
 {% endhighlight %}
 
+h3. Exercises
+* Expand the project- and context-tag generation code to filter out duplicate entries.
+** Some Todo.txt users like to insert project and context tags inside the description of their to-do items.  Add code to identify these tags and filter them out of the end tags.
+

chapters/design_patterns/decorator.textile

@@ -8,10 +8,9 @@ h2. Problem
 
 You have a set of data that you need to process in multiple, possibly varying ways.
 
-
 h2. Solution
 
-Use the Decorator pattern to structure the application of changes.
+Use the Decorator pattern in order to structure how you apply the changes.
 
 {% highlight coffeescript %}
 miniMarkdown = (line) ->
@@ -26,7 +25,7 @@ miniMarkdown = (line) ->
             ''
 
 stripComments = (line) ->
-    line.replace /\s*\/\/.*$/, ''
+    line.replace /\s*\/\/.*$/, '' # Removes one-line, double-slash C-style comments
 
 TextProcessor = (processors) ->
     processors: processors
@@ -55,11 +54,21 @@ processor.processString exampleText
 # => "<h1>A level 1 header</h1>\n<p>A regular line</p>\n\n<h2>A level 2 header</h2>\n<p>A line</p>"
 {% endhighlight %}
 
+h3. Results
+
+{% highlight html %}
+<h1>A level 1 header</h1>
+<p>A regular line</p>
+
+<h2>A level 1 header</h2>
+<p>A line</p>
+{% endhighlight %}
+
 h2. Discussion
 
-The TextProcessor serves the role of Decorator and binds the individual, specialized text processors together.  This frees up the miniMarkdown, stripComments, and any future components to focus on handling nothing but a single line of text.  Future developers only have to write functions that return a string and add it to the array of processors.
+The TextProcessor serves the role of Decorator by binding the individual, specialized text processors together.  This frees up the miniMarkdown and stripComments components to focus on handling nothing but a single line of text.  Future developers only have to write functions that return a string and add it to the array of processors.
 
-We can even modify the existing Decorator object on the fly.  We could add a processor for transforming text smilies into images, for example, but only when the end user enables the feature:
+We can even modify the existing Decorator object on the fly:
 
 {% highlight coffeescript %}
 smilies =

chapters/design_patterns/strategy.textile

@@ -6,7 +6,7 @@ chapter: Design Patterns
 
 h2. Problem
 
-You have more than one way to solve a problem but you need to choose (or even switch) between them at run time.
+You have more than one way to solve a problem but you need to choose (or even switch) between these methods at run time.
 
 h2. Solution
 
@@ -69,7 +69,7 @@ sorter.sort unsortedList
 
 h2. Discussion
 
-Like a skilled general, we must prepare to change our plans under constantly-changing circumstances.  At the end of the example, we know that only the newest item in the array is out of order.  We can then speed the sort up by switching to an algorithm that starts from the end of the array.
+"No plan survives first contact with the enemy", nor users, but we can use the knowledge gained from changing circumstances to adapt.  Near the end of the example, for instance, the newest item in the array now lies out of order.  Knowing that detail, we can then speed the sort up by switching to an algorithm optimized for that exact scenario with nothing but a simple reassignment.
 
 h3. Exercises
 

wanted-recipes.textile

@@ -133,7 +133,6 @@ h2. Design patterns
 ** Adapter
 ** Bridge
 ** Composite
-** Decorator
 ** Facade
 ** Flyweight
 ** Proxy