[update JMacro tutorial to discuss the new ToMessage behavior
Jeremy Shaw <jeremy@seereason.com>**20120705184732
 Ignore-this: c1be295c84c3b275ecd6b6b4bead332f
] hunk ./JMacro.markdown.lhs 70
-> import Happstack.Server.JMacro      ()                -- ToMessage instance for JStat
+> import Happstack.Server.JMacro      (jmResponse)                -- ToMessage instance for JStat
hunk ./JMacro.markdown.lhs 498
->      fun greet noun
+>      window.greet = function (noun)
hunk ./JMacro.markdown.lhs 507
-Then we have a server part with two sub-parts:
+Notice that we attached the `greet` function to the `window`. The `ToMessage` instance for `JStat` wraps the Javascript in an anonymous function to ensure that statements execute in a local scope. That helps prevents namespace collisions between different external scripts. But, it also means that top-level unhygienic variables will not be global available. So we need to attach them to the `window`.
+
+Next we have a server part with two sub-parts:
hunk ./JMacro.markdown.lhs 517
+
hunk ./JMacro.markdown.lhs 519
+
hunk ./JMacro.markdown.lhs 527
+
hunk ./JMacro.markdown.lhs 529
+
hunk ./JMacro.markdown.lhs 543
+Instead of attaching the `greet` function to the `window`, we could instead use `jmResponse` to serve the `JStat`. `jmResponse` does not wrap the Javascript in an anonymous function so the `window` work-around is not needed. We do need to use `!` to make sure the name of the `greet2` function is not mangled though:
+
+<div class="code">
+
+> externalJs2 :: String -> JStat
+> externalJs2 greeting =
+>     [$jmacro|
+>      function !greet2 (noun)
+>      {
+>        alert(`(greeting)` + ' ' + noun);
+>      }
+>      |]
+>
+>
+> externalPart2 :: JMacroPart Response
+> externalPart2 = dir "external2" $ msum
+>           [ dir "script.js" $
+>                do greeting <- optional $ look "greeting"
+>                   jmResponse $ externalJs2 (fromMaybe "hello" greeting)
+>
+>          , toResponse <$> defaultTemplate "external 2"
+>              <script type="text/javascript" src="/external2/script.js?greeting=Ahoy" />
+>              <div>
+>               <h1>Greetings</h1>
+>               <button onclick=[$jmacro| greet2('JMacro'); |]>Click for a greeting.</button>
+>              </div>
+>          ]
+>
+
+</div>
+
hunk ./JMacro.markdown.lhs 593
+>                     <li><a href="/external2" >External 2</a></li>
hunk ./JMacro.markdown.lhs 612
+>         , externalPart2