[Start regexp introduction.
Bryan O'Sullivan <bos@serpentine.com>**20070608070815
 Long delay caused by writing of ghci session recorder.
] {
hunk ./en/00book.xml 26
+<!ENTITY regexp.ghci:typetwiddle SYSTEM "regexp.ghci:typetwiddle.xml">
hunk ./en/Makefile 8
-src-examples = \
+src-examples := \
hunk ./en/Makefile 10
-	ch07/glob-to-regexp/GlobWithRegex.hs
+	ch07/glob-to-regexp/GlobWithRegex.hs \
+	ch07/regexp.ghci
+
+src-ghci := $(filter %.ghci,$(src-examples))
hunk ./en/Makefile 31
-xmlto-opts := --skip-validation
+xmlto-opts := --skip-validation --searchpath '$(CURDIR)'
hunk ./en/Makefile 99
-	cat .stamp-*.hs | sort > all-entities.txt
-	grep '^<!ENTITY .*\.hs:.*\.xml' 00book.xml | sort > book-entities.txt
+	cat .stamp-*.ghci .stamp-*.hs | sort > all-entities.txt
+	grep '^<!ENTITY .*\.[a-z]*:.*\.xml' 00book.xml | sort > book-entities.txt
hunk ./en/Makefile 113
+vpath %.ghci $(addprefix ../examples/,$(dir $(src-examples)))
hunk ./en/Makefile 115
-.stamp-%: %
+.stamp-%.hs: %.hs
hunk ./en/Makefile 118
+.stamp-%.ghci: %.ghci
+	../tools/bin/ghcisession $(CURDIR) $< > $@
+
hunk ./en/ch07-globs-and-regexps.xml 39
-      referred to as <quote>glob patterns</quote>, <quote>wildcard
-	patterns</quote>, or <quote>shell-style patterns</quote>.
-      These patterns have just a few simple rules.</para>
+      referred to as <quote>glob patterns</quote> (the term we'll
+      use), <quote>wildcard patterns</quote>, or <quote>shell-style
+	patterns</quote>.  These patterns have just a few simple
+      rules.</para>
hunk ./en/ch07-globs-and-regexps.xml 91
+
+    <para>While Haskell doesn't provide a glob matching function, it
+      has excellent regular expression matching facilities.  Glob
+      patterns are nothing more than restricted regular expressions
+      with slightly different syntax.  It's easy to convert glob
+      patterns into regular expressions, so we'll take that tack
+      initially.  But in order to do so, we must first understand how
+      to use regular expressions in Haskell.</para>
+  </sect1>
+
+  <sect1>
+    <title>Regular expressions in Haskell</title>
+
+    <para>In this section, I'll be assuming that you are already
+      familiar with regular expressions (which I'll abbreviate as
+      <emphasis>regexps</emphasis> from here on) by way of some other
+      language, such as Python, Perl, or Java.  Rather than introduce
+      them as something new, I'll be focusing on what's different
+      about regexp handling in Haskell, compared to imperative
+      languages.</para>
+
+    <para>The first hurdle to overcome is that Haskell's regexp
+      library makes heavy use of polymorphism; as a result, many of
+      its type signatures are difficult to understand.</para>
+&regexp.ghci:typetwiddle;
}