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-rw-r--r--doc/regexp.n35
1 files changed, 26 insertions, 9 deletions
diff --git a/doc/regexp.n b/doc/regexp.n
index 100f0d8..5e857f8 100644
--- a/doc/regexp.n
+++ b/doc/regexp.n
@@ -10,11 +10,9 @@
'\" Note: do not modify the .SH NAME line immediately below!
.SH NAME
regexp \- Match a regular expression against a string
-
.SH SYNOPSIS
\fBregexp \fR?\fIswitches\fR? \fIexp string \fR?\fImatchVar\fR? ?\fIsubMatchVar subMatchVar ...\fR?
.BE
-
.SH DESCRIPTION
.PP
Determines whether the regular expression \fIexp\fR matches part or
@@ -22,7 +20,7 @@ all of \fIstring\fR and returns 1 if it does, 0 if it does not, unless
\fB\-inline\fR is specified (see below).
(Regular expression matching is described in the \fBre_syntax\fR
reference page.)
-.LP
+.PP
If additional arguments are specified after \fIstring\fR then they
are treated as the names of variables in which to return
information about which part(s) of \fIstring\fR matched \fIexp\fR.
@@ -38,6 +36,7 @@ they are treated as switches. The following switches are
currently supported:
.TP 15
\fB\-about\fR
+.
Instead of attempting to match the regular expression, returns a list
containing information about the regular expression. The first
element of the list is a subexpression count. The second element is a
@@ -45,11 +44,13 @@ list of property names that describe various attributes of the regular
expression. This switch is primarily intended for debugging purposes.
.TP 15
\fB\-expanded\fR
+.
Enables use of the expanded regular expression syntax where
whitespace and comments are ignored. This is the same as specifying
the \fB(?x)\fR embedded option (see the \fBre_syntax\fR manual page).
.TP 15
\fB\-indices\fR
+.
Changes what is stored in the \fIsubMatchVar\fRs.
Instead of storing the matching characters from \fIstring\fR,
each variable
@@ -58,6 +59,7 @@ in \fIstring\fR of the first and last characters in the matching
range of characters.
.TP 15
\fB\-line\fR
+.
Enables newline-sensitive matching. By default, newline is a
completely ordinary character with no special meaning. With this
flag,
@@ -75,6 +77,7 @@ specifying both \fB\-linestop\fR and \fB\-lineanchor\fR, or the
\fB(?n)\fR embedded option (see the \fBre_syntax\fR manual page).
.TP 15
\fB\-linestop\fR
+.
Changes the behavior of
.QW [^
bracket expressions and
@@ -84,6 +87,7 @@ stop at newlines. This is the same as specifying the \fB(?p)\fR
embedded option (see the \fBre_syntax\fR manual page).
.TP 15
\fB\-lineanchor\fR
+.
Changes the behavior of
.QW ^
and
@@ -96,16 +100,19 @@ specifying the \fB(?w)\fR embedded option (see the \fBre_syntax\fR
manual page).
.TP 15
\fB\-nocase\fR
+.
Causes upper-case characters in \fIstring\fR to be treated as
lower case during the matching process.
.TP 15
\fB\-all\fR
+.
Causes the regular expression to be matched as many times as possible
in the string, returning the total number of matches found. If this
is specified with match variables, they will contain information for
the last match only.
.TP 15
\fB\-inline\fR
+.
Causes the command to return, as a list, the data that would otherwise
be placed in match variables. When using \fB\-inline\fR,
match variables may not be specified. If used with \fB\-all\fR, the
@@ -113,20 +120,22 @@ list will be concatenated at each iteration, such that a flat list is
always returned. For each match iteration, the command will append the
overall match data, plus one element for each subexpression in the
regular expression. Examples are:
+.RS
+.PP
.CS
\fBregexp\fR -inline -- {\ew(\ew)} " inlined "
\fI\(-> in n\fR
\fBregexp\fR -all -inline -- {\ew(\ew)} " inlined "
\fI\(-> in n li i ne e\fR
.CE
+.RE
.TP 15
\fB\-start\fR \fIindex\fR
+.
Specifies a character index offset into the string to start
matching the regular expression at.
-.VS 8.5
The \fIindex\fR value is interpreted in the same manner
as the \fIindex\fR argument to \fBstring index\fR.
-.VE 8.5
When using this switch,
.QW ^
will not match the beginning of the line, and \eA will still
@@ -136,6 +145,7 @@ absolute beginning of the input string.
\fIindex\fR will be constrained to the bounds of the input string.
.TP 15
\fB\-\|\-\fR
+.
Marks the end of switches. The argument following this one will
be treated as \fIexp\fR even if it starts with a \fB\-\fR.
.PP
@@ -151,9 +161,11 @@ if \fB\-indices\fR has been specified or to an empty string otherwise.
Find the first occurrence of a word starting with \fBfoo\fR in a
string that is not actually an instance of \fBfoobar\fR, and get the
letters following it up to the end of the word into a variable:
+.PP
.CS
\fBregexp\fR {\emfoo(?!bar\eM)(\ew*)} $string \-> restOfWord
.CE
+.PP
Note that the whole matched substring has been placed in the variable
.QW \fB\->\fR ,
which is a name chosen to look nice given that we are not
@@ -161,17 +173,21 @@ actually interested in its contents.
.PP
Find the index of the word \fBbadger\fR (in any case) within a string
and store that in the variable \fBlocation\fR:
+.PP
.CS
\fBregexp\fR \-indices {(?i)\embadger\eM} $string location
.CE
+.PP
This could also be written as a \fIbasic\fR regular expression (as opposed
to using the default syntax of \fIadvanced\fR regular expressions) match by
prefixing the expression with a suitable flag:
+.PP
.CS
\fBregexp\fR \-indices {(?ib)\e<badger\e>} $string location
.CE
.PP
This counts the number of octal digits in a string:
+.PP
.CS
\fBregexp\fR \-all {[0\-7]} $string
.CE
@@ -179,13 +195,14 @@ This counts the number of octal digits in a string:
This lists all words (consisting of all sequences of non-whitespace
characters) in a string, and is useful as a more powerful version of the
\fBsplit\fR command:
+.PP
.CS
\fBregexp\fR \-all \-inline {\eS+} $string
.CE
.SH "SEE ALSO"
-re_syntax(n), regsub(n),
-.VS 8.5
-string(n)
-.VE
+re_syntax(n), regsub(n), string(n)
.SH KEYWORDS
match, parsing, pattern, regular expression, splitting, string
+'\" Local Variables:
+'\" mode: nroff
+'\" End: