 @@ -1,14 +1,14 @@
-.\"	$NetBSD: re_format.7,v 1.9 2009/04/21 14:46:02 joerg Exp $
+.\"	$NetBSD: re_format.7,v 1.10 2013/01/25 11:51:42 wiz Exp $
 .\"
 .\" Copyright (c) 1992, 1993, 1994
 .\"	The Regents of the University of California.  All rights reserved.
 .\"
 .\" This code is derived from software contributed to Berkeley by
 .\" Henry Spencer.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
 .\" modification, are permitted provided that the following conditions
 .\" are met:
 .\" 1. Redistributions of source code must retain the above copyright
 .\"    notice, this list of conditions and the following disclaimer.
 .\" 2. Redistributions in binary form must reproduce the above copyright
 @@ -73,105 +73,105 @@
 .Nd POSIX 1003.2 regular expressions
 .Sh DESCRIPTION
 Regular expressions (``RE''s),
 as defined in POSIX 1003.2, come in two forms:
 modern REs (roughly those of
 .Xr egrep 1 ;
 .2 calls these ``extended'' REs)
 and obsolete REs (roughly those of
 .Xr ed 1 ;
 .2 ``basic'' REs).
 Obsolete REs mostly exist for backward compatibility in some old programs;
 they will be discussed at the end.
 .2 leaves some aspects of RE syntax and semantics open;
-`\(dg' marks decisions on these aspects that
+`#' marks decisions on these aspects that
 may not be fully portable to other 1003.2 implementations.
 .Pp
-A (modern) RE is one\(dg or more non-empty\(dg
+A (modern) RE is one# or more non-empty#
 .Em branches ,
 separated by `|'.
 It matches anything that matches one of the branches.
 .Pp
-A branch is one\(dg or more
+A branch is one# or more
 .Em pieces ,
 concatenated.
 It matches a match for the first, followed by a match for the second, etc.
 .Pp
 A piece is an
 .Em atom
 possibly followed
-by a single\(dg `*', `+', `?', or
+by a single# `*', `+', `?', or
 .Em bound .
 An atom followed by `*' matches a sequence of 0 or more matches of the atom.
 An atom followed by `+' matches a sequence of 1 or more matches of the atom.
 An atom followed by `?' matches a sequence of 0 or 1 matches of the atom.
 .Pp
+A
 .Em bound
 is `{' followed by an unsigned decimal integer, possibly followed by `,'
 possibly followed by another unsigned decimal integer,
 always followed by `}'.
-The integers must lie between 0 and RE_DUP_MAX (255\(dg) inclusive,
+The integers must lie between 0 and RE_DUP_MAX (255#) inclusive,
 and if there are two of them, the first may not exceed the second.
 An atom followed by a bound containing one integer
 .Em i
 and no comma matches a sequence of exactly
 .Em i
 matches of the atom.
 An atom followed by a bound containing one integer
 .Em i
 and a comma matches a sequence of
 .Em i
 or more matches of the atom.
 An atom followed by a bound containing two integers
 .Em i
 and
 .Em j
 matches a sequence of
 .Em i
 through
 .Em j
 (inclusive) matches of the atom.
 .Pp
 An atom is a regular expression enclosed in `()' (matching a match for the
-regular expression), an empty set of `()' (matching the null string)\(dg, a
+regular expression), an empty set of `()' (matching the null string)#, a
 .Em bracket expression
 (see below), `.' (matching any single character),
 `^' (matching the null string at the beginning of a line),
 `$' (matching the null string at the end of a line),
 a `\e' followed by one of the characters `^.[$()|*+?{\e'
 (matching that character taken as an ordinary character),
-a `\e' followed by any other character\(dg
+a `\e' followed by any other character#
 (matching that character taken as an ordinary character,
-as if the `\e' had not been present\(dg),
+as if the `\e' had not been present#),
 or a single character with no other significance (matching that character).
 A `{' followed by a character other than a digit is an ordinary
-character, not the beginning of a bound\(dg.
+character, not the beginning of a bound#.
 It is illegal to end an RE with `\e'.
 .Pp
+A
 .Em bracket expression
 is a list of characters enclosed in `[]'.
 It normally matches any single character from the list (but see below).
 If the list begins with `^',
 it matches any single character (but see below)
 .Em not
 from the rest of the list.
 If two characters in the list are separated by `\-', this is shorthand
 for the full
 .Em range
 of characters between those two (inclusive) in the collating sequence,
 e.g. `[0-9]' in ASCII matches any decimal digit.
-It is illegal\(dg for two ranges to share an endpoint, e.g. `a-c-e'.
+It is illegal# for two ranges to share an endpoint, e.g. `a-c-e'.
 Ranges are very collating-sequence-dependent,
 and portable programs should avoid relying on them.
 .Pp
 To include a literal `]' in the list, make it the first character
 (following a possible `^').
 To include a literal `\-', make it the first or last character,
 or the second endpoint of a range.
 To use a literal `\-' as the first endpoint of a range,
 enclose it in `[.' and `.]' to make it a collating element (see below).
 With the exception of these and some combinations using `[' (see next
 paragraphs), all other special characters, including `\e', lose their
 special significance within a bracket expression.
 .Pp
 @@ -184,47 +184,47 @@ The sequence is a single element of the
 A bracket expression containing a multi-character collating element
 can thus match more than one character,
 e.g. if the collating sequence includes a `ch' collating element,
 then the RE `[[.ch.]]*c' matches the first five characters
 of `chchcc'.
 .Pp
 Within a bracket expression, a collating element enclosed in `[=' and
 `=]' is an equivalence class, standing for the sequences of characters
 of all collating elements equivalent to that one, including itself.
 (If there are no other equivalent collating elements,
 the treatment is as if the enclosing delimiters were `[.' and `.]'.)
 For example, if o and '\(^o' are the members of an equivalence class,
 then `[[=o=]]', `[[=\(^o'=]]', and `[o\(^o']' are all synonymous.
-An equivalence class may not\(dg be an endpoint
+An equivalence class may not# be an endpoint
 of a range.
 .Pp
 Within a bracket expression, the name of a
 .Em character class
 enclosed in `[:' and `:]' stands for the list of all characters
 belonging to that class.
 Standard character class names are:
 .Bl -column "alnum" "digit" "xdigit"
 .It alnum	digit	punct
 .It alpha	graph	space
 .It blank	lower	upper
 .It cntrl	print	xdigit
 .El
 .Pp
 These stand for the character classes defined in
 .Xr ctype 3 .
 A locale may provide others.
 A character class may not be used as an endpoint of a range.
 .Pp
-There are two special cases\(dg of bracket expressions:
+There are two special cases# of bracket expressions:
 the bracket expressions `[[:\*[Lt]:]]' and `[[:\*[Gt]:]]' match
 the null string at the beginning and end of a word respectively.
 A word is defined as a sequence of word characters
 which is neither preceded nor followed by word characters.
 A word character is an
 .Em alnum
 character (as defined by
 .Xr ctype 3 )
 or an underscore.
 This is an extension, compatible with but not specified by POSIX 1003.2,
 and should be used with caution in software intended to be portable
 to other systems.
 .Pp
 @@ -250,43 +250,43 @@ when `(a*)*' is matched against `bc' bot
 subexpression match the null string.
 .Pp
 If case-independent matching is specified,
 the effect is much as if all case distinctions had vanished from the
 alphabet.
 When an alphabetic that exists in multiple cases appears as an
 ordinary character outside a bracket expression, it is effectively
 transformed into a bracket expression containing both cases,
 e.g. `x' becomes `[xX]'.
 When it appears inside a bracket expression, all case counterparts
 of it are added to the bracket expression, so that (e.g.) `[x]'
 becomes `[xX]' and `[^x]' becomes `[^xX]'.
 .Pp
-No particular limit is imposed on the length of REs\(dg.
+No particular limit is imposed on the length of REs#.
 Programs intended to be portable should not employ REs longer
 than 256 bytes,
 as an implementation can refuse to accept such REs and remain
 POSIX-compliant.
 .Pp
 Obsolete (``basic'') regular expressions differ in several respects.
 `|', `+', and `?' are ordinary characters and there is no equivalent
 for their functionality.
 The delimiters for bounds are `\e{' and `\e}',
 with `{' and `}' by themselves ordinary characters.
 The parentheses for nested subexpressions are `\e(' and `\e)',
 with `(' and `)' by themselves ordinary characters.
 `^' is an ordinary character except at the beginning of the
-RE or\(dg the beginning of a parenthesized subexpression,
+RE or# the beginning of a parenthesized subexpression,
 `$' is an ordinary character except at the end of the
-RE or\(dg the end of a parenthesized subexpression,
+RE or# the end of a parenthesized subexpression,
 and `*' is an ordinary character if it appears at the beginning of the
 RE or the beginning of a parenthesized subexpression
 (after a possible leading `^').
 Finally, there is one new type of atom, a
 .Em back reference :
 `\e' followed by a non-zero decimal digit
 .Em d
 matches the same sequence of characters
 matched by the
 .Em d Ns th parenthesized subexpression
 (numbering subexpressions by the positions of their opening parentheses,
 left to right),
 so that (e.g.) `\e([bc]\e)\e1' matches `bb' or `cc' but not `bc'.