Added documentation for inflections (closes #5013) [m.stienstra@fngtps.com]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4428 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/lib/active_support/core_ext/string/inflections.rb

@@ -2,16 +2,35 @@ require File.dirname(__FILE__) + '/../../inflector' unless defined? Inflector
 module ActiveSupport #:nodoc:
   module CoreExtensions #:nodoc:
     module String #:nodoc:
-      # Makes it possible to do "posts".singularize that returns "post" and "MegaCoolClass".underscore that returns "mega_cool_class".
+      # String inflections define new methods on the String class to transform names for different purposes.
+      # For instance, you can figure out the name of a database from the name of a class.
+      #   "ScaleScore".tableize => "scale_scores"
       module Inflections
+        
+        # Returns the plural form of the word in the string.
+        #
+        # Examples
+        #   "post".pluralize #=> "posts"
+        #   "sheep".pluralize #=> "sheep"
+        #   "the blue mailman".pluralize #=> "the blue mailmen"
         def pluralize
           Inflector.pluralize(self)
         end
 
+        # The reverse of pluralize, returns the singular form of a word in a string.
+        #
+        # Examples
+        #   "posts".singularize => "post"
+        #   "the blue mailmen".pluralize #=> "the blue mailman"
         def singularize
           Inflector.singularize(self)
         end
 
+        # Creates a camelcased name from an underscored name. CamelCased names LookLikeThis and under_scored_names look_like_this.
+        #
+        # Examples
+        #   "active_record".camelize #=> "ActiveRecord"
+        #   "raw_scaled_scorer".camelize #=> "RawScaledScorer"
         def camelize(first_letter = :upper)
           case first_letter
             when :upper then Inflector.camelize(self, true)
@@ -20,41 +39,84 @@ module ActiveSupport #:nodoc:
         end
         alias_method :camelcase, :camelize
 
+        # Capitalizes all the words and replaces some characters in the string to create a nicer looking title.
+        #
+        # Examples
+        #   "man from the boondocks".titleize #=> "Man From The Boondocks"
+        #   "x-men: the last stand".titleize #=> "X Men: The Last Stand"
         def titleize
           Inflector.titleize(self)
         end
         alias_method :titlecase, :titleize
 
+        # The reverse of +camelize+. Makes an underscored form from the expression in the string.
+        #
+        # Examples
+        #   "ActiveRecord".underscore #=> "active_record"
+        #   "RawScaledScore".underscore #=> "raw_scaled_score"
         def underscore
           Inflector.underscore(self)
         end
 
+        # Replaces underscores with dashes in the string
+        #
+        # Example
+        #   "puni_puni" #=> "puni-puni"
         def dasherize
           Inflector.dasherize(self)
         end
 
+        # Removes the module part from the expression in the string
+        #
+        # Examples
+        #   "ActiveRecord::CoreExtensions::String::Inflections".demodulize #=> "Inflections"
+        #   "Inflections".demodulize #=> "Inflections"
         def demodulize
           Inflector.demodulize(self)
         end
 
+        # Create the name of a table like Rails does for models to table names.
+        #
+        # Examples
+        #   "RawScaledScorer".tableize #=> "raw_scaled_scorers"
+        #   "egg_and_ham".tableize #=> "egg_and_hams"
         def tableize
           Inflector.tableize(self)
         end
 
+        # Create a class name from a table name like Rails does for table names to models. Note that this returns a string and not a Class.
+        #
+        # Examples
+        #   "egg_and_hams".classify #=> "EggAndHam"
+        #   "post".classify #=> "Post"
         def classify
           Inflector.classify(self)
         end
         
-        # Capitalizes the first word and turns underscores into spaces and strips _id, so "employee_salary" becomes "Employee salary" 
-        # and "author_id" becomes "Author".
+        # Capitalizes the first word and turns underscores into spaces and strips _id.
+        #
+        # Examples
+        #   "employee_salary" #=> "Employee salary" 
+        #   "author_id" #=> "Author"
         def humanize
           Inflector.humanize(self)
         end
 
+        # Creates a foreign key name from a class name. +separate_class_name_and_id_with_underscore+ sets whether the method should put '_' between the name and 'id'.
+        #
+        # Examples
+        #   "Message".foreign_key #=> "message_id"
+        #   "Message".foreign_key(false) #=> "messageid"
+        #   "Admin::Post".foreign_key #=> "post_id"
         def foreign_key(separate_class_name_and_id_with_underscore = true)
           Inflector.foreign_key(self, separate_class_name_and_id_with_underscore)
         end
 
+        # Constantize tries to find a declared constant with the name specified in the string. It raises a NameError when the name is not in CamelCase or is not initialized.
+        #
+        # Examples
+        #   "Module".constantize #=> Module
+        #   "Class".constantize #=> Class
         def constantize
           Inflector.constantize(self)
         end