[Added path.lhs
Jeremy Shaw <jeremy@seereason.com>**20100522173721
 Ignore-this: 37a94f8916fb8543d459f65d4d9b8c50
] hunk ./Makefile 6
-DEMOS := Dir.lhs Dir2.lhs Dirs.lhs
+DEMOS := Dir.lhs Dir2.lhs Dirs.lhs Path.lhs
hunk ./Makefile 13
-RouteFilters.html: MonadPlus.lhs Dir.lhs Dir2.lhs Dirs.lhs
+RouteFilters.html: MonadPlus.lhs Dir.lhs Dir2.lhs Dirs.lhs Path.lhs
addfile ./Path.lhs
hunk ./Path.lhs 1
+<!--
hunk ./Path.lhs 3
+> {-# LANGUAGE CPP #-}
+
+-->
+
+<h2>Matching on dynamic path segments</h2>
+
+<h3><code>path</code></h3>
+
+<p>Often times a path segment will contain a variable value we want to
+extract and use, such as a number or a string. We can use the
+<code>path</code> combinator to do that.</p>
+
+#ifdef HsColour
+> path :: (FromReqURI a, MonadPlus m, ServerMonad m) => (a -> m b) -> m b
+#endif
+
+<p><code>path</code> will attempt to extract and decode a path
+segment, and if it succeeds, it will pass the decode value the nested
+server part.</p>
+
+<p>Let's start with the most basic example, extracting a
+<code>String</code> value. We will extend the Hello World server so
+that we can say hello to anyone.</p>
+
+> module Main where
+>
+> import Control.Monad (msum)
+> import Happstack.Server (nullConf, simpleHTTP, ok, dir, path)
+>
+> main :: IO ()
+> main = simpleHTTP nullConf $ msum [ dir "hello" $ path $ \s -> ok $ "Hello, " ++ s
+>                                   ]
+
+<p class="source-code">[Source code for the app is <a href="Path.hs">here.</a>]</p>
+
+<p>Now, if we start the app and point our browser at:  <a href="http://localhost:8000/hello/World">http://localhost:8000/hello/World</a> we get the "Hello, World". <p>if we point it at <a href="http://localhost:8000/hello/Haskell">http://localhost:8000/hello/Haskell</a>, we get "Hello, Haskell".</p>
hunk ./RouteFilters.lhs 27
-
+#include "Path.lhs"