Dev guide: add sections and an example on hosted apps. Re nvaccess#4569.

developerGuide.t2t

@@ -171,13 +171,14 @@ The following few sections will talk separately about App Modules and Global Plu
 After this point, discussion is again more general.
 
 ++ Basics of an App Module ++
-App Module files have a .py extension, and are named the same as the main executable of the application for which you wish them to be used.
+App Module files have a .py extension, and are named the same as either the main executable of the application for which you wish them to be used or the package inside a host executable.
 For example, an App Module for notepad would be called notepad.py, as notepad's main executable is called notepad.exe.
+For apps hosted inside host executables, see the section on app modules for hosted apps.
 
 App Module files must be placed in the appModules subdirectory of the user's NVDA user configuration directory.
 For more information on where to find the user configuration directory, please see the NVDA user guide.
 
-App Modules must define a class called AppModule, which inherits from appModuleHandler.AppModule.
+App Modules must define a class called AppModule, which inherits from appModuleHandler.AppModule unless specified otherwise.
 This class can then define event and script methods, gesture bindings and other code.
 This will all be covered in depth later.
 
@@ -228,6 +229,44 @@ Events will be covered in greater detail later.
 
 As with other examples in this guide, remember to delete the created app module when you are finished testing and then restart NVDA or reload plugins, so that original functionality is restored.
 
+++ App modules for hosted apps ++
+Some executables host various apps inside.
+These include javaw.exe for running various java programs and wwahost.exe for web apps in Windows 8 and later.
+
+If an app runs inside a host executable, the name of the app module must be the name as defined by the host executable, which can be found through AppModule.appName property.
+For example, an app module for a java app named "test" hosted inside javaw.exe must be named test.py.
+For apps hosted inside wwahost, not only the app module name must be the name of the loaded app, but the app module must subclass the app module class found in wwahost.
+
+Note that wwahost.exe hosts web applications or apps behaving as such.
+You should create an app module for apps hosted inside it if you believe the hosted app is not a true web application.
+This is the case for built-in apps such as Mail and Calendar in Windows 8 and 8.1.
+
+++ Example 2: an app module for an app hosted by wwahost.exe ++
+The following example is same as Notepad app module above except this is for an app hosted by wwahost.exe.
+
+```
+--- start ---
+# wwahost/test App Module for NVDA
+# Developer guide example 2
+
+from nvdaBuiltin.appModules.wwahost import *
+
+class AppModule(AppModule):
+
+	def event_gainFocus(self, obj, nextHandler):
+		import tones
+		tones.beep(550, 50)
+		nextHandler()
+
+--- end ---
+```
+
+The biggest difference from Notepad app module is where wwahost app module comes from.
+As a built-in app module, wwahost can be imported from nvdaBuiltin.appModules.
+
+Another difference is how the app module class is defined.
+As wwahost app module provides necessary infrastructure for apps hosted inside, you just need to subclass the wwahost AppModule class.
+
 ++ Basics of a Global Plugin ++
 Global Plugin files have a .py extension, and should have a short unique name which identifies what they do.
 
@@ -240,7 +279,7 @@ This will all be covered in depth later.
 
 NVDA loads all global plugins as soon as it starts, and unloads them on exit.
 
-++ Example 2: a Global Plugin Providing a Script to Announce the NVDA Version ++
+++ Example 3: a Global Plugin Providing a Script to Announce the NVDA Version ++
 The following example Global Plugin Allows you to press NVDA+shift+v while anywhere in the Operating System to find out NVDA's version.
 This example is only to show you the basic layout of a Global Plugin.
 
@@ -254,7 +293,7 @@ From anywhere, you can now press NVDA+shift+v to have NVDA's version spoken and
 ```
 --- start ---
 # Version announcement plugin for NVDA
-# Developer guide example 2
+# Developer guide example 3
 
 import globalPluginHandler
 from scriptHandler import script
@@ -435,7 +474,7 @@ This dictionary should contain gesture identifier strings pointing to the name o
 You can also specify a description of the script in the function's docstring.
 Furthermore, an alternative way of specifying the script's category is by means of setting a "category" attribute on the script function to a string containing the name of the category.
 
-++ Example 3: A Global Plugin to Find out Window Class and Control ID ++
+++ Example 4: A Global Plugin to Find out Window Class and Control ID ++
 The following Global Plugin allows you to press NVDA+leftArrow to have the window class of the current focus announced, and NVDA+rightArrow to have the window control ID of the current focus announced.
 This example shows you how to define one or more scripts and gesture bindings on a class such as an App Module, Global Plugin or NVDA Object.
 
@@ -447,7 +486,7 @@ Once saved in the right place, either restart NVDA or choose Reload Plugins foun
 ```
 --- start ---
 #Window utility scripts for NVDA
-#Developer guide example 3
+#Developer guide example 4
 
 import globalPluginHandler
 from scriptHandler import script
@@ -529,7 +568,7 @@ Sleep Mode is very useful for self voicing applications that have their own scre
 Although sleep mode can be toggled on and off by the user with the key command NVDA+shift+s, a developer can choose to have sleep mode enabled by default for an application.
 This is done by providing an App Module for that application which simply sets sleepMode to True in the AppModule class.
 
-++ Example 4: A Sleep Mode App Module ++
+++ Example 5: A Sleep Mode App Module ++
 
 The following code can be copied and pasted in to a text file, then saved in the appModules directory with the name of the application you wish to enable sleep mode for.
 As always, the file must have a .py extension.
@@ -573,7 +612,7 @@ Inside this method, you should decide which custom NVDA Object class(es) (if any
 If a custom class should be used, it must be inserted into the class list, usually at the beginning.
 You can also remove classes chosen by NVDA from the class list, although this is rarely required.
 
-++ Example 5: Command to Retrieve the Length of Text in an Edit Field Using a Custom NVDA Object ++
+++ Example 6: Command to Retrieve the Length of Text in an Edit Field Using a Custom NVDA Object ++
 This app module for notepad provides a command to report the number of characters in edit fields.
 You can activate it using NVDA+l.
 Notice that the command is specific to edit fields; i.e. it only works while you are focused in an edit field, rather than anywhere in the application.
@@ -615,7 +654,7 @@ The event_NVDAObject_init method takes two arguments:
 
 Inside this method, you can check whether this object is relevant and then override properties accordingly.
 
-++ Example 6: Labelling the Notepad Edit Field Using event_NVDAObject_init ++
+++ Example 7: Labelling the Notepad Edit Field Using event_NVDAObject_init ++
 This app module for notepad makes NVDA report Notepad's main edit field as having a name of "content".
 That is, when it receives focus, NVDA will say "Content edit".