[Working on chapter 5
John Goerzen <jgoerzen@complete.org>**20070603212324] {
adddir ./examples/ch05
hunk ./en/00book.xml 19
+<!ENTITY naiveeq.hs:color SYSTEM "naiveeq.hs:color.xml">
hunk ./en/ch05-typeclasses.xml 19
-      you resolved to implement your own equality tests.  Your program
+      you resolved to implement your own equality tests.  Your application
hunk ./en/ch05-typeclasses.xml 22
-      this:
+      <xref linkend="hs.typeclasses.ex.naiveeq"/>.
+    </para>
+    <example id="hs.typeclasses.ex.naiveeq">
+      <title>Naive Equality naiveeq.hs</title>
+      &naiveeq.hs:color;
+    </example>
+    <para>
+      You can test this with <application>ghci</application> or
+      <application>hugs</application>:
+    </para>
+    <screen>
+$ <userinput>ghci naiveeq.hs</userinput>
+Loading package base ... linking ... done.
+[1 of 1] Compiling Main             ( naiveeq.hs, interpreted )
+Ok, modules loaded: Main.
+*Main&gt; <userinput>colorEq Red Red</userinput>
+True
+*Main&gt; <userinput>colorEq Red Blue</userinput>
+False
+</screen>
+    <para>
+      Now, let's say that you want to add 
addfile ./examples/ch05/naiveeq.hs
hunk ./examples/ch05/naiveeq.hs 1
+{-- snippet color --}
+data Color = Red | Green | Blue
+
+colorEq :: Color -> Color -> Bool
+colorEq Red Red = True
+colorEq Red _ = False
+colorEq Green Green = True
+colorEq Green _ = False
+colorEq Blue Blue = True
+colorEq Blue _ = False
+{-- /snippet color --}
+
}