Small nits only.
diff --git a/Doc/libregex.tex b/Doc/libregex.tex
index 45e7249..f2e094a 100644
--- a/Doc/libregex.tex
+++ b/Doc/libregex.tex
@@ -4,8 +4,8 @@
This module provides regular expression matching operations similar to
those found in Emacs. It is always available.
-By default the patterns are Emacs-style regular expressions,
-with one exception. There is
+By default the patterns are Emacs-style regular expressions
+(with one exception). There is
a way to change the syntax to match that of several well-known
\UNIX{} utilities. The exception is that Emacs' \samp{\e s}
pattern is not supported, since the original implementation references
@@ -36,7 +36,8 @@
A regular expression (or RE) specifies a set of strings that matches
it; the functions in this module let you check if a particular string
-matches a given regular expression.
+matches a given regular expression (or if a given regular expression
+matches a particular string, which comes down to the same thing).
Regular expressions can be concatenated to form new regular
expressions; if \emph{A} and \emph{B} are both regular expressions,
@@ -51,22 +52,23 @@
% "Compilers: Principles, Techniques and Tools", by Alfred V. Aho,
% Ravi Sethi, and Jeffrey D. Ullman, or some FA text.
-A brief explanation of the format of regular
-expressions follows.
+A brief explanation of the format of regular expressions follows.
Regular expressions can contain both special and ordinary characters.
Ordinary characters, like '\code{A}', '\code{a}', or '\code{0}', are
the simplest regular expressions; they simply match themselves. You
can concatenate ordinary characters, so '\code{last}' matches the
-characters 'last'.
+characters 'last'. (In the rest of this section, we'll write RE's in
+\code{this special font}, usually without quotes, and strings to be
+matched 'in single quotes'.)
Special characters either stand for classes of ordinary characters, or
affect how the regular expressions around them are interpreted.
The special characters are:
\begin{itemize}
-\item[\code{.}]{Matches any character except a newline.}
-\item[\code{\^}]{Matches the start of the string.}
+\item[\code{.}]{(Dot.) Matches any character except a newline.}
+\item[\code{\^}]{(Caret.) Matches the start of the string.}
\item[\code{\$}]{Matches the end of the string.
\code{foo} matches both 'foo' and 'foobar', while the regular
expression '\code{foo\$}' matches only 'foo'.}
@@ -114,7 +116,8 @@
\begin{itemize}
\item[\code{\e|}]\code{A\e|B}, where A and B can be arbitrary REs,
-creates a regular expression that will match either A or B.
+creates a regular expression that will match either A or B. This can
+be used inside groups (see below) as well.
%
\item[\code{\e( \e)}]{Indicates the start and end of a group; the
contents of a group can be matched later in the string with the
@@ -126,7 +129,8 @@
'55 55', but not 'the end' (note the space after the group). This
special sequence can only be used to match one of the first 9 groups;
groups with higher numbers can be matched using the \code{\e v}
-sequence.}}
+sequence. (\code{\e 8} and \code{\e 9} don't need a double backslash
+because they are not octal digits.)}}
%
\item[\code{\e \e b}]{Matches the empty string, but only at the
beginning or end of a word. A word is defined as a sequence of
@@ -151,6 +155,8 @@
\item[\code{\e >}]{Matches the empty string, but only at the end of a
word.}
+\item[\code{\e \e \e \e}]{Matches a literal backslash.}
+
% In Emacs, the following two are start of buffer/end of buffer. In
% Python they seem to be synonyms for ^$.
\item[\code{\e `}]{Like \code{\^}, this only matches at the start of the
@@ -175,7 +181,7 @@
\begin{funcdesc}{search}{pattern\, string}
Return the first position in \var{string} that matches the regular
- expression \var{pattern}. Return -1 if no position in the string
+ expression \var{pattern}. Return \code{-1} if no position in the string
matches the pattern (this is different from a zero-length match
anywhere!).
\end{funcdesc}