[Add bibliographic info
Bryan O'Sullivan <bos@serpentine.com>**20080312050754] {
hunk ./en/bibliography.xml 3
+  
+  <biblioentry id="bib.hughes95">
+    <abbrev>Hughes95</abbrev>
+    <biblioset relation="article">
+      <author><firstname>John</firstname><surname>Hughes</surname></author>
+      <title><ulink
+	  url="http://citeseer.ist.psu.edu/hughes95design.html">The
+	  design of a pretty-printing library</ulink></title>
+    </biblioset>
+    <confgroup>
+      <confdates>May, 1995</confdates>
+      <conftitle>First International Spring School on Advanced
+	Functional Programming Techniques</conftitle>
+      <address>Bastad, Sweden</address>
+    </confgroup>
+  </biblioentry>
hunk ./en/bibliography.xml 89
+
+  <biblioentry id="bib.wadler98">
+    <abbrev>Wadler98</abbrev>
+    <biblioset relation="article">
+      <author><firstname>Philip</firstname><surname>Wadler</surname></author>
+      <title><ulink
+	  url="http://citeseer.ist.psu.edu/wadler98prettier.html">A
+	  prettier printer</ulink></title>
+      <pubdate>March 1998</pubdate>
+    </biblioset>
+  </biblioentry>
hunk ./en/ch06-library.xml 1017
-      <para>We can make a number of interesting improvements to our
-	pretty printer.</para>
+      <para>Our current pretty printer is spartan to fit within our
+	space constraints, but there are a number of useful
+	improvements we can make.</para>
hunk ./en/ch06-library.xml 1022
+	<qandaentry>
+	  <question>
+	    <para>Write a function, <function>fill</function>:</para>
+
+	    &Prettify.hs:fill;
+
+	    <para>It should render the document, then add spaces so
+	      that the rendered text is the given number of columns
+	      wide.  If the text is already wider than this value, it
+	      should add no spaces.</para>
+	  </question>
+	</qandaentry>
+
hunk ./en/ch06-library.xml 1053
+  </sect1>
hunk ./en/ch06-library.xml 1055
-    <sect2>
-      <title>Practical pointers, and further reading</title>
+  <sect1>
+    <title>Practical pointers, and further reading</title>
hunk ./en/ch06-library.xml 1058
-      <para>Blah.</para>
-    </sect2>
+    <para>&GHC; already bundles a pretty printing library,
+      <code>Text.PrettyPrint.HughesPJ</code>.  It provides the same
+      basic API as our example, but a much richer and more useful set
+      of pretty printing functions.  We recommend using it, rather
+      than writing your own.</para>
+
+    <para>The design of the <code>HughesPJ</code> pretty printer was
+      introduced by John Hughes in <citation><biblioref
+	  linkend="bib.hughes95"/></citation>. The library was
+      subsequently improved by Simon Peyton Jones, hence the name.
+      Hughes's paper is long, but well worth reading for his
+      discussion of how to design a library in Haskell.</para>
+
+    <para>In this chapter, our pretty printing library is based on a
+      simpler model described in <citation><biblioref
+	  linkend="bib.wadler98"/></citation>.  His library was
+      extended by Daan Leijen; this version is available for download
+      from Hackage.</para>
hunk ./examples/ch06/Prettify.hs 153
+
+{-- snippet fill --}
+fill :: Int -> Doc -> Doc
+{-- /snippet fill --}
+fill = undefined
}