add some text to the opening few sections of the mod_lua doc

explaining briefly why we're here.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1154261 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/docs/manual/mod/mod_lua.xml b/docs/manual/mod/mod_lua.xml
index 328d70f224442a9b7fba3ade13781e351910269e..ca6068e9d2d82482e7dae80e04a46f03c7b1844b 100644 (file)
--- a/docs/manual/mod/mod_lua.xml
+++ b/docs/manual/mod/mod_lua.xml
@@ -32,9 +32,15 @@ request processing</description>
 <compatibility>2.3 and later</compatibility>
 
 <summary>
-<p>Someone needs to write this.
-Include a link to <a href="http://www.lua.org/">the Lua website</a>.
-</p>
+<p>This module allows the server to be extended with scripts written in the 
+Lua programming language.  The extension points (hooks) available with
+<module>mod_lua</module> include many of the hooks available to
+natively compiled Apache HTTP Server modules, such as mapping requests to
+files, generating dynamic responses, access control, authentication, and 
+authorization</p>
+
+<p>More information on the Lua programming language can be found at the 
+<a href="http://www.lua.org/">the Lua website</a>.</p>
 
 <note><code>mod_lua</code> is still in experimental state.
 Until it is declared stable, usage and behavior may change
@@ -70,8 +76,12 @@ ending in <code>.lua</code> by invoking that file's
 </section>
 
 <section id="writinghandlers"><title>Writing Handlers</title>
+<p> In the Apache HTTP Server API, the handler is a specific kind of hook
+responsible for generating the response.  Examples of modules that include a 
+handler are <module>mod_proxy</module>, <module>mod_cgi</module>, 
+and <module>mod_status</module>.</p>
 
-<p><code>mod_lua</code> always looks to invoke a function for the handler, rather than
+<p><code>mod_lua</code> always looks to invoke a Lua function for the handler, rather than
 just evaluating a script body CGI style. A handler function looks
 something like this:</p>
 
@@ -112,6 +122,12 @@ handlers (or hooks, or filters) in the same script.
 
 <section id="writinghooks"><title>Writing Hooks</title>
 
+<p>Hook functions are how modules (and Lua scripts) participate in the
+processing of requests. Each type of hook exposed by the server exists for 
+a specific purposes such as mapping requests to the filesystem, 
+performing access control, or setting mimetypes.  General purpose hooks
+that simply run at handy times in the request lifecycle exist as well.</p>
+
 <p>Hook functions are passed the request object as their only argument.
 They can return any value, depending on the hook, but most commonly
 they'll return OK, DONE, or DECLINED, which you can write in lua as