changeset 7146:f0b6593e5fab

* regexprops-generic.texi: Add a copyright notice.
author Paul Eggert <eggert@cs.ucla.edu>
date Tue, 15 Aug 2006 21:48:33 +0000
parents 0162db7320a2
children 1388e7363d86
files doc/ChangeLog doc/regexprops-generic.texi
diffstat 2 files changed, 127 insertions(+), 113 deletions(-) [+]
line wrap: on
line diff
--- a/doc/ChangeLog
+++ b/doc/ChangeLog
@@ -1,3 +1,7 @@
+2006-08-15  Paul Eggert  <eggert@cs.ucla.edu>
+
+	* regexprops-generic.texi: Add a copyright notice.
+
 2006-08-14  Paul Eggert  <eggert@cs.ucla.edu>
 
 	Add copyright notices to long-enough files that lack them, since
--- a/doc/regexprops-generic.texi
+++ b/doc/regexprops-generic.texi
@@ -1,3 +1,13 @@
+@c Copyright (C) 1994, 1996, 1998, 2000, 2001, 2003, 2004, 2005, 2006
+@c Free Software Foundation, Inc.
+
+@c Permission is granted to copy, distribute and/or modify this document
+@c under the terms of the GNU Free Documentation License, Version 1.2 or
+@c any later version published by the Free Software Foundation; with no
+@c Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
+@c Texts.  A copy of the license is included in the ``GNU Free
+@c Documentation License'' file as part of this distribution.
+
 @menu
 * awk regular expression syntax::
 * egrep regular expression syntax::
@@ -17,38 +27,38 @@
 @subsection @samp{awk} regular expression syntax
 
 
-The character @samp{.} matches any single character except the null character.  
+The character @samp{.} matches any single character except the null character.
 
 
 @table @samp
 
 @item +
-indicates that the regular expression should match one or more occurrences of the previous atom or regexp.  
+indicates that the regular expression should match one or more occurrences of the previous atom or regexp.
 @item ?
-indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.  
+indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.
 @item \+
 matches a @samp{+}
 @item \?
-matches a @samp{?}.  
+matches a @samp{?}.
 @end table
 
 
-Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are invalid.  Within square brackets, @samp{\} can be used to quote the following character.  Character classes are not supported, so for example you would need to use @samp{[0-9]} instead of @samp{[[:digit:]]}.  
+Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are invalid.  Within square brackets, @samp{\} can be used to quote the following character.  Character classes are not supported, so for example you would need to use @samp{[0-9]} instead of @samp{[[:digit:]]}.
 
-GNU extensions are not supported and so @samp{\w}, @samp{\W}, @samp{\<}, @samp{\>}, @samp{\b}, @samp{\B}, @samp{\`}, and @samp{\'} match @samp{w}, @samp{W}, @samp{<}, @samp{>}, @samp{b}, @samp{B}, @samp{`}, and @samp{'} respectively.  
+GNU extensions are not supported and so @samp{\w}, @samp{\W}, @samp{\<}, @samp{\>}, @samp{\b}, @samp{\B}, @samp{\`}, and @samp{\'} match @samp{w}, @samp{W}, @samp{<}, @samp{>}, @samp{b}, @samp{B}, @samp{`}, and @samp{'} respectively.
 
-Grouping is performed with parentheses @samp{()}.  An unmatched @samp{)} matches just itself.  A backslash followed by a digit matches that digit.  
+Grouping is performed with parentheses @samp{()}.  An unmatched @samp{)} matches just itself.  A backslash followed by a digit matches that digit.
 
-The alternation operator is @samp{|}.  
+The alternation operator is @samp{|}.
 
-The characters @samp{^} and @samp{$} always represent the beginning and end of a string respectively, except within square brackets.  Within brackets, @samp{^} can be used to invert the membership of the character class being specified.  
+The characters @samp{^} and @samp{$} always represent the beginning and end of a string respectively, except within square brackets.  Within brackets, @samp{^} can be used to invert the membership of the character class being specified.
 
 @samp{*}, @samp{+} and @samp{?} are special at any point in a regular expression except:
 @enumerate
 
 @item At the beginning of a regular expression
 
-@item After an open-group, signified by 
+@item After an open-group, signified by
 @samp{(}
 @item After the alternation operator @samp{|}
 
@@ -57,30 +67,30 @@
 
 
 
-The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.  
+The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.
 
 
 @node egrep regular expression syntax
 @subsection @samp{egrep} regular expression syntax
 
 
-The character @samp{.} matches any single character except newline.  
+The character @samp{.} matches any single character except newline.
 
 
 @table @samp
 
 @item +
-indicates that the regular expression should match one or more occurrences of the previous atom or regexp.  
+indicates that the regular expression should match one or more occurrences of the previous atom or regexp.
 @item ?
-indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.  
+indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.
 @item \+
 matches a @samp{+}
 @item \?
-matches a @samp{?}.  
+matches a @samp{?}.
 @end table
 
 
-Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are ignored.  Within square brackets, @samp{\} is taken literally.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.  Non-matching lists @samp{[^@dots{}]} do not ever match newline.  
+Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are ignored.  Within square brackets, @samp{\} is taken literally.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.  Non-matching lists @samp{[^@dots{}]} do not ever match newline.
 
 GNU extensions are supported:
 @enumerate
@@ -104,38 +114,38 @@
 @end enumerate
 
 
-Grouping is performed with parentheses @samp{()}.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{(}.  
+Grouping is performed with parentheses @samp{()}.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{(}.
 
-The alternation operator is @samp{|}.  
+The alternation operator is @samp{|}.
 
-The characters @samp{^} and @samp{$} always represent the beginning and end of a string respectively, except within square brackets.  Within brackets, @samp{^} can be used to invert the membership of the character class being specified.  
+The characters @samp{^} and @samp{$} always represent the beginning and end of a string respectively, except within square brackets.  Within brackets, @samp{^} can be used to invert the membership of the character class being specified.
 
-The characters @samp{*}, @samp{+} and @samp{?} are special anywhere in a regular expression.  
+The characters @samp{*}, @samp{+} and @samp{?} are special anywhere in a regular expression.
 
 
 
-The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.  
+The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.
 
 
 @node ed regular expression syntax
 @subsection @samp{ed} regular expression syntax
 
 
-The character @samp{.} matches any single character except the null character.  
+The character @samp{.} matches any single character except the null character.
 
 
 @table @samp
 
 @item \+
-indicates that the regular expression should match one or more occurrences of the previous atom or regexp.  
+indicates that the regular expression should match one or more occurrences of the previous atom or regexp.
 @item \?
-indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.  
-@item + and ? 
-match themselves.  
+indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.
+@item + and ?
+match themselves.
 @end table
 
 
-Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are invalid.  Within square brackets, @samp{\} is taken literally.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.  
+Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are invalid.  Within square brackets, @samp{\} is taken literally.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.
 
 GNU extensions are supported:
 @enumerate
@@ -159,17 +169,17 @@
 @end enumerate
 
 
-Grouping is performed with backslashes followed by parentheses @samp{\(}, @samp{\)}.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{\(}.  
+Grouping is performed with backslashes followed by parentheses @samp{\(}, @samp{\)}.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{\(}.
 
-The alternation operator is @samp{\|}. 
+The alternation operator is @samp{\|}.
 
 The character @samp{^} only represents the beginning of a string when it appears:
 @enumerate
 
-@item 
+@item
 At the beginning of a regular expression
 
-@item After an open-group, signified by 
+@item After an open-group, signified by
 @samp{\(}
 
 @item After the alternation operator @samp{\|}
@@ -182,7 +192,7 @@
 
 @item At the end of a regular expression
 
-@item Before an close-group, signified by 
+@item Before an close-group, signified by
 @samp{\)}
 @item Before the alternation operator @samp{\|}
 
@@ -194,39 +204,39 @@
 
 @item At the beginning of a regular expression
 
-@item After an open-group, signified by 
+@item After an open-group, signified by
 @samp{\(}
 @item After the alternation operator @samp{\|}
 
 @end enumerate
 
 
-Intervals are specified by @samp{\@{} and @samp{\@}}.  Invalid intervals such as @samp{a\@{1z} are not accepted.  
+Intervals are specified by @samp{\@{} and @samp{\@}}.  Invalid intervals such as @samp{a\@{1z} are not accepted.
 
-The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.  
+The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.
 
 
 @node emacs regular expression syntax
 @subsection @samp{emacs} regular expression syntax
 
 
-The character @samp{.} matches any single character except newline.  
+The character @samp{.} matches any single character except newline.
 
 
 @table @samp
 
 @item +
-indicates that the regular expression should match one or more occurrences of the previous atom or regexp.  
+indicates that the regular expression should match one or more occurrences of the previous atom or regexp.
 @item ?
-indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.  
+indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.
 @item \+
 matches a @samp{+}
 @item \?
-matches a @samp{?}.  
+matches a @samp{?}.
 @end table
 
 
-Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are ignored.  Within square brackets, @samp{\} is taken literally.  Character classes are not supported, so for example you would need to use @samp{[0-9]} instead of @samp{[[:digit:]]}.  
+Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are ignored.  Within square brackets, @samp{\} is taken literally.  Character classes are not supported, so for example you would need to use @samp{[0-9]} instead of @samp{[[:digit:]]}.
 
 GNU extensions are supported:
 @enumerate
@@ -250,17 +260,17 @@
 @end enumerate
 
 
-Grouping is performed with backslashes followed by parentheses @samp{\(}, @samp{\)}.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{\(}.  
+Grouping is performed with backslashes followed by parentheses @samp{\(}, @samp{\)}.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{\(}.
 
-The alternation operator is @samp{\|}. 
+The alternation operator is @samp{\|}.
 
 The character @samp{^} only represents the beginning of a string when it appears:
 @enumerate
 
-@item 
+@item
 At the beginning of a regular expression
 
-@item After an open-group, signified by 
+@item After an open-group, signified by
 @samp{\(}
 
 @item After the alternation operator @samp{\|}
@@ -273,7 +283,7 @@
 
 @item At the end of a regular expression
 
-@item Before an close-group, signified by 
+@item Before an close-group, signified by
 @samp{\)}
 @item Before the alternation operator @samp{\|}
 
@@ -285,7 +295,7 @@
 
 @item At the beginning of a regular expression
 
-@item After an open-group, signified by 
+@item After an open-group, signified by
 @samp{\(}
 @item After the alternation operator @samp{\|}
 
@@ -294,30 +304,30 @@
 
 
 
-The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.  
+The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.
 
 
 @node gnu-awk regular expression syntax
 @subsection @samp{gnu-awk} regular expression syntax
 
 
-The character @samp{.} matches any single character.  
+The character @samp{.} matches any single character.
 
 
 @table @samp
 
 @item +
-indicates that the regular expression should match one or more occurrences of the previous atom or regexp.  
+indicates that the regular expression should match one or more occurrences of the previous atom or regexp.
 @item ?
-indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.  
+indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.
 @item \+
 matches a @samp{+}
 @item \?
-matches a @samp{?}.  
+matches a @samp{?}.
 @end table
 
 
-Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are invalid.  Within square brackets, @samp{\} can be used to quote the following character.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.  
+Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are invalid.  Within square brackets, @samp{\} can be used to quote the following character.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.
 
 GNU extensions are supported:
 @enumerate
@@ -341,18 +351,18 @@
 @end enumerate
 
 
-Grouping is performed with parentheses @samp{()}.  An unmatched @samp{)} matches just itself.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{(}.  
+Grouping is performed with parentheses @samp{()}.  An unmatched @samp{)} matches just itself.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{(}.
 
-The alternation operator is @samp{|}.  
+The alternation operator is @samp{|}.
 
-The characters @samp{^} and @samp{$} always represent the beginning and end of a string respectively, except within square brackets.  Within brackets, @samp{^} can be used to invert the membership of the character class being specified.  
+The characters @samp{^} and @samp{$} always represent the beginning and end of a string respectively, except within square brackets.  Within brackets, @samp{^} can be used to invert the membership of the character class being specified.
 
 @samp{*}, @samp{+} and @samp{?} are special at any point in a regular expression except:
 @enumerate
 
 @item At the beginning of a regular expression
 
-@item After an open-group, signified by 
+@item After an open-group, signified by
 @samp{(}
 @item After the alternation operator @samp{|}
 
@@ -361,28 +371,28 @@
 
 
 
-The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.  
+The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.
 
 
 @node grep regular expression syntax
 @subsection @samp{grep} regular expression syntax
 
 
-The character @samp{.} matches any single character except newline.  
+The character @samp{.} matches any single character except newline.
 
 
 @table @samp
 
 @item \+
-indicates that the regular expression should match one or more occurrences of the previous atom or regexp.  
+indicates that the regular expression should match one or more occurrences of the previous atom or regexp.
 @item \?
-indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.  
-@item + and ? 
-match themselves.  
+indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.
+@item + and ?
+match themselves.
 @end table
 
 
-Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are ignored.  Within square brackets, @samp{\} is taken literally.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.  Non-matching lists @samp{[^@dots{}]} do not ever match newline.  
+Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are ignored.  Within square brackets, @samp{\} is taken literally.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.  Non-matching lists @samp{[^@dots{}]} do not ever match newline.
 
 GNU extensions are supported:
 @enumerate
@@ -406,17 +416,17 @@
 @end enumerate
 
 
-Grouping is performed with backslashes followed by parentheses @samp{\(}, @samp{\)}.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{\(}.  
+Grouping is performed with backslashes followed by parentheses @samp{\(}, @samp{\)}.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{\(}.
 
-The alternation operator is @samp{\|}. 
+The alternation operator is @samp{\|}.
 
 The character @samp{^} only represents the beginning of a string when it appears:
 @enumerate
 
-@item 
+@item
 At the beginning of a regular expression
 
-@item After an open-group, signified by 
+@item After an open-group, signified by
 @samp{\(}
 
 @item After a newline
@@ -431,7 +441,7 @@
 
 @item At the end of a regular expression
 
-@item Before an close-group, signified by 
+@item Before an close-group, signified by
 @samp{\)}
 @item Before a newline
 
@@ -445,7 +455,7 @@
 
 @item At the beginning of a regular expression
 
-@item After an open-group, signified by 
+@item After an open-group, signified by
 @samp{\(}
 @item After a newline
 
@@ -454,56 +464,56 @@
 @end enumerate
 
 
-Intervals are specified by @samp{\@{} and @samp{\@}}.  Invalid intervals such as @samp{a\@{1z} are not accepted.  
+Intervals are specified by @samp{\@{} and @samp{\@}}.  Invalid intervals such as @samp{a\@{1z} are not accepted.
 
-The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.  
+The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.
 
 
 @node posix-awk regular expression syntax
 @subsection @samp{posix-awk} regular expression syntax
 
 
-The character @samp{.} matches any single character except the null character.  
+The character @samp{.} matches any single character except the null character.
 
 
 @table @samp
 
 @item +
-indicates that the regular expression should match one or more occurrences of the previous atom or regexp.  
+indicates that the regular expression should match one or more occurrences of the previous atom or regexp.
 @item ?
-indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.  
+indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.
 @item \+
 matches a @samp{+}
 @item \?
-matches a @samp{?}.  
+matches a @samp{?}.
 @end table
 
 
-Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are invalid.  Within square brackets, @samp{\} can be used to quote the following character.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.  
+Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are invalid.  Within square brackets, @samp{\} can be used to quote the following character.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.
 
-GNU extensions are not supported and so @samp{\w}, @samp{\W}, @samp{\<}, @samp{\>}, @samp{\b}, @samp{\B}, @samp{\`}, and @samp{\'} match @samp{w}, @samp{W}, @samp{<}, @samp{>}, @samp{b}, @samp{B}, @samp{`}, and @samp{'} respectively.  
+GNU extensions are not supported and so @samp{\w}, @samp{\W}, @samp{\<}, @samp{\>}, @samp{\b}, @samp{\B}, @samp{\`}, and @samp{\'} match @samp{w}, @samp{W}, @samp{<}, @samp{>}, @samp{b}, @samp{B}, @samp{`}, and @samp{'} respectively.
 
-Grouping is performed with parentheses @samp{()}.  An unmatched @samp{)} matches just itself.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{(}.  
+Grouping is performed with parentheses @samp{()}.  An unmatched @samp{)} matches just itself.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{(}.
 
-The alternation operator is @samp{|}.  
+The alternation operator is @samp{|}.
 
-The characters @samp{^} and @samp{$} always represent the beginning and end of a string respectively, except within square brackets.  Within brackets, @samp{^} can be used to invert the membership of the character class being specified.  
+The characters @samp{^} and @samp{$} always represent the beginning and end of a string respectively, except within square brackets.  Within brackets, @samp{^} can be used to invert the membership of the character class being specified.
 
 @samp{*}, @samp{+} and @samp{?} are special at any point in a regular expression except the following places, where they are illegal:
 @enumerate
 
 @item At the beginning of a regular expression
 
-@item After an open-group, signified by 
+@item After an open-group, signified by
 @samp{(}
 @item After the alternation operator @samp{|}
 
 @end enumerate
 
 
-Intervals are specified by @samp{@{} and @samp{@}}.  Invalid intervals such as @samp{a@{1z} are not accepted.  
+Intervals are specified by @samp{@{} and @samp{@}}.  Invalid intervals such as @samp{a@{1z} are not accepted.
 
-The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.  
+The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.
 
 
 @node posix-basic regular expression syntax
@@ -513,23 +523,23 @@
 @subsection @samp{posix-egrep} regular expression syntax
 
 
-The character @samp{.} matches any single character except newline.  
+The character @samp{.} matches any single character except newline.
 
 
 @table @samp
 
 @item +
-indicates that the regular expression should match one or more occurrences of the previous atom or regexp.  
+indicates that the regular expression should match one or more occurrences of the previous atom or regexp.
 @item ?
-indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.  
+indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.
 @item \+
 matches a @samp{+}
 @item \?
-matches a @samp{?}.  
+matches a @samp{?}.
 @end table
 
 
-Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are ignored.  Within square brackets, @samp{\} is taken literally.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.  Non-matching lists @samp{[^@dots{}]} do not ever match newline.  
+Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are ignored.  Within square brackets, @samp{\} is taken literally.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.  Non-matching lists @samp{[^@dots{}]} do not ever match newline.
 
 GNU extensions are supported:
 @enumerate
@@ -553,40 +563,40 @@
 @end enumerate
 
 
-Grouping is performed with parentheses @samp{()}.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{(}.  
+Grouping is performed with parentheses @samp{()}.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{(}.
 
-The alternation operator is @samp{|}.  
+The alternation operator is @samp{|}.
 
-The characters @samp{^} and @samp{$} always represent the beginning and end of a string respectively, except within square brackets.  Within brackets, @samp{^} can be used to invert the membership of the character class being specified.  
+The characters @samp{^} and @samp{$} always represent the beginning and end of a string respectively, except within square brackets.  Within brackets, @samp{^} can be used to invert the membership of the character class being specified.
 
-The characters @samp{*}, @samp{+} and @samp{?} are special anywhere in a regular expression.  
+The characters @samp{*}, @samp{+} and @samp{?} are special anywhere in a regular expression.
 
 Intervals are specified by @samp{@{} and @samp{@}}.  Invalid intervals are treated as literals, for example @samp{a@{1} is treated as @samp{a\@{1}
 
-The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.  
+The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.
 
 
 @node posix-extended regular expression syntax
 @subsection @samp{posix-extended} regular expression syntax
 
 
-The character @samp{.} matches any single character except the null character.  
+The character @samp{.} matches any single character except the null character.
 
 
 @table @samp
 
 @item +
-indicates that the regular expression should match one or more occurrences of the previous atom or regexp.  
+indicates that the regular expression should match one or more occurrences of the previous atom or regexp.
 @item ?
-indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.  
+indicates that the regular expression should match zero or one occurrence of the previous atom or regexp.
 @item \+
 matches a @samp{+}
 @item \?
-matches a @samp{?}.  
+matches a @samp{?}.
 @end table
 
 
-Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are invalid.  Within square brackets, @samp{\} is taken literally.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.  
+Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are invalid.  Within square brackets, @samp{\} is taken literally.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.
 
 GNU extensions are supported:
 @enumerate
@@ -610,38 +620,38 @@
 @end enumerate
 
 
-Grouping is performed with parentheses @samp{()}.  An unmatched @samp{)} matches just itself.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{(}.  
+Grouping is performed with parentheses @samp{()}.  An unmatched @samp{)} matches just itself.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{(}.
 
-The alternation operator is @samp{|}.  
+The alternation operator is @samp{|}.
 
-The characters @samp{^} and @samp{$} always represent the beginning and end of a string respectively, except within square brackets.  Within brackets, @samp{^} can be used to invert the membership of the character class being specified.  
+The characters @samp{^} and @samp{$} always represent the beginning and end of a string respectively, except within square brackets.  Within brackets, @samp{^} can be used to invert the membership of the character class being specified.
 
 @samp{*}, @samp{+} and @samp{?} are special at any point in a regular expression except the following places, where they are illegal:
 @enumerate
 
 @item At the beginning of a regular expression
 
-@item After an open-group, signified by 
+@item After an open-group, signified by
 @samp{(}
 @item After the alternation operator @samp{|}
 
 @end enumerate
 
 
-Intervals are specified by @samp{@{} and @samp{@}}.  Invalid intervals such as @samp{a@{1z} are not accepted.  
+Intervals are specified by @samp{@{} and @samp{@}}.  Invalid intervals such as @samp{a@{1z} are not accepted.
 
-The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.  
+The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.
 
 
 @node posix-minimal-basic regular expression syntax
 @subsection @samp{posix-minimal-basic} regular expression syntax
 
 
-The character @samp{.} matches any single character except the null character.  
+The character @samp{.} matches any single character except the null character.
 
 
 
-Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are invalid.  Within square brackets, @samp{\} is taken literally.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.  
+Bracket expressions are used to match ranges of characters.  Bracket expressions where the range is backward, for example @samp{[z-a]}, are invalid.  Within square brackets, @samp{\} is taken literally.  Character classes are supported; for example @samp{[[:digit:]]} will match a single decimal digit.
 
 GNU extensions are supported:
 @enumerate
@@ -665,17 +675,17 @@
 @end enumerate
 
 
-Grouping is performed with backslashes followed by parentheses @samp{\(}, @samp{\)}.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{\(}.  
+Grouping is performed with backslashes followed by parentheses @samp{\(}, @samp{\)}.  A backslash followed by a digit acts as a back-reference and matches the same thing as the previous grouped expression indicated by that number.  For example @samp{\2} matches the second group expression.  The order of group expressions is determined by the position of their opening parenthesis @samp{\(}.
 
 
 
 The character @samp{^} only represents the beginning of a string when it appears:
 @enumerate
 
-@item 
+@item
 At the beginning of a regular expression
 
-@item After an open-group, signified by 
+@item After an open-group, signified by
 @samp{\(}
 
 @end enumerate
@@ -686,18 +696,18 @@
 
 @item At the end of a regular expression
 
-@item Before an close-group, signified by 
+@item Before an close-group, signified by
 @samp{\)}
 @end enumerate
 
 
 
 
-Intervals are specified by @samp{\@{} and @samp{\@}}.  Invalid intervals such as @samp{a\@{1z} are not accepted.  
+Intervals are specified by @samp{\@{} and @samp{\@}}.  Invalid intervals such as @samp{a\@{1z} are not accepted.
 
-The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.  
+The longest possible match is returned; this applies to the regular expression as a whole and (subject to this constraint) to subexpressions within groups.
 
 
 @node sed regular expression syntax
 @subsection @samp{sed} regular expression syntax
-This is a synonym for ed.
\ No newline at end of file
+This is a synonym for ed.