Document the hook module.

lib/guard/hook.rb

@@ -1,51 +1,80 @@
 module Guard
+
+  # Guard has a hook mechanism that allows you to insert callbacks for individual Guards.
+  # By default, each of the Guard instance methods has a "_begin" and an "_end" hook.
+  # For example, the Guard::Guard#start method has a :start_begin hook that is run immediately
+  # before Guard::Guard#start and a :start_end hook that is run immediately after Guard::Guard#start.
+  #
+  # Read more about [hooks and callbacks on the wiki](https://github.com/guard/guard/wiki/Hooks-and-callbacks).
+  #
   module Hook
 
+    # The Hook module gets included.
+    #
+    # @param [Class] base the class that includes the module
+    #
     def self.included(base)
       base.send :include, InstanceMethods
     end
 
+    # Instance methods that gets included in the base class.
+    #
     module InstanceMethods
-      # When +event+ is a Symbol, #hook will generate a hook name
-      # by concatenating the method name from where #hook is called
+
+      # When +event+ is a Symbol, {#hook} will generate a hook name
+      # by concatenating the method name from where {#hook} is called
       # with the given Symbol.
-      # Example:
+      #
+      # @example Add a hook with a Symbol
       #   def run_all
       #     hook :foo
       #   end
-      # Here, when #run_all is called, #hook will notify callbacks
+      #
+      # Here, when {Guard::Guard#run_all} is called, {#hook} will notify callbacks
       # registered for the "run_all_foo" event.
       #
-      # When +event+ is a String, #hook will directly turn the String
+      # When +event+ is a String, {#hook} will directly turn the String
       # into a Symbol.
-      # Example:
+      #
+      # @example Add a hook with a String
       #   def run_all
       #     hook "foo_bar"
       #   end
-      # Here, when #run_all is called, #hook will notify callbacks
+      #
+      # When {Guard::Guard#run_all} is called, {#hook} will notify callbacks
       # registered for the "foo_bar" event.
       #
-      # +args+ parameter is passed as is to the callbacks registered
-      # for the given event.
+      # @param [Symbol, String] event the name of the Guard event
+      # @param [Array] args the parameters are passed as is to the callbacks registered for the given event.
+      #
       def hook(event, *args)
         hook_name = if event.is_a? Symbol
-          calling_method = caller[0][/`([^']*)'/, 1]
-          "#{calling_method}_#{event}"
-        else
-          event
-        end.to_sym
+                      calling_method = caller[0][/`([^']*)'/, 1]
+                      "#{ calling_method }_#{ event }"
+                    else
+                      event
+                    end.to_sym
 
-        UI.debug "Hook :#{hook_name} executed for #{self.class}"
+        UI.debug "Hook :#{ hook_name } executed for #{ self.class }"
 
         Hook.notify(self.class, hook_name, *args)
       end
     end
 
     class << self
+
+      # Get all callbacks
+      #
       def callbacks
         @callbacks ||= Hash.new { |hash, key| hash[key] = [] }
       end
 
+      # Add a callback.
+      #
+      # @param [Block] listener the listener to notify
+      # @param [Guard::Guard] guard_class the Guard class to add the callback
+      # @param [Array<Symbol>] events the events to register
+      #
       def add_callback(listener, guard_class, events)
         _events = events.is_a?(Array) ? events : [events]
         _events.each do |event|
@@ -53,19 +82,34 @@ module Guard
         end
       end
 
+      # Checks if a callback has been registered.
+      #
+      # @param [Block] listener the listener to notify
+      # @param [Guard::Guard] guard_class the Guard class to add the callback
+      # @param [Symbol] event the event to look for
+      #
       def has_callback?(listener, guard_class, event)
         callbacks[[guard_class, event]].include?(listener)
       end
 
+      # Notify a callback.
+      #
+      # @param [Guard::Guard] guard_class the Guard class to add the callback
+      # @param [Symbol] event the event to trigger
+      # @param [Array] args the arguments for the listener
+      #
       def notify(guard_class, event, *args)
         callbacks[[guard_class, event]].each do |listener|
           listener.call(guard_class, event, *args)
         end
       end
 
+      # Reset all callbacks
+      #
       def reset_callbacks!
         @callbacks = nil
       end
+
     end
 
   end