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diff --git a/doc/regexp.n b/doc/regexp.n deleted file mode 100644 index ed61c8d..0000000 --- a/doc/regexp.n +++ /dev/null @@ -1,145 +0,0 @@ -'\" -'\" Copyright (c) 1993 The Regents of the University of California. -'\" Copyright (c) 1994-1996 Sun Microsystems, Inc. -'\" -'\" See the file "license.terms" for information on usage and redistribution -'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. -'\" -'\" RCS: @(#) $Id: regexp.n,v 1.2 1998/09/14 18:39:54 stanton Exp $ -'\" -.so man.macros -.TH regexp n "" Tcl "Tcl Built-In Commands" -.BS -'\" 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 -all of \fIstring\fR and returns 1 if it does, 0 if it doesn't. -.LP -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. -\fIMatchVar\fR will be set to the range of \fIstring\fR that -matched all of \fIexp\fR. The first \fIsubMatchVar\fR will contain -the characters in \fIstring\fR that matched the leftmost parenthesized -subexpression within \fIexp\fR, the next \fIsubMatchVar\fR will -contain the characters that matched the next parenthesized -subexpression to the right in \fIexp\fR, and so on. -.LP -If the initial arguments to \fBregexp\fR start with \fB\-\fR then -they are treated as switches. The following switches are -currently supported: -.TP 10 -\fB\-nocase\fR -Causes upper-case characters in \fIstring\fR to be treated as -lower case during the matching process. -.TP 10 -\fB\-indices\fR -Changes what is stored in the \fIsubMatchVar\fRs. -Instead of storing the matching characters from \fBstring\fR, -each variable -will contain a list of two decimal strings giving the indices -in \fIstring\fR of the first and last characters in the matching -range of characters. -.TP 10 -\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. -.LP -If there are more \fIsubMatchVar\fR's than parenthesized -subexpressions within \fIexp\fR, or if a particular subexpression -in \fIexp\fR doesn't match the string (e.g. because it was in a -portion of the expression that wasn't matched), then the corresponding -\fIsubMatchVar\fR will be set to ``\fB\-1 \-1\fR'' if \fB\-indices\fR -has been specified or to an empty string otherwise. - -.SH "REGULAR EXPRESSIONS" -.PP -Regular expressions are implemented using Henry Spencer's package -(thanks, Henry!), -and much of the description of regular expressions below is copied verbatim -from his manual entry. -.PP -A regular expression is zero or more \fIbranches\fR, separated by ``|''. -It matches anything that matches one of the branches. -.PP -A branch is zero or more \fIpieces\fR, concatenated. -It matches a match for the first, followed by a match for the second, etc. -.PP -A piece is an \fIatom\fR possibly followed by ``*'', ``+'', or ``?''. -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 match of the atom, or the null string. -.PP -An atom is a regular expression in parentheses (matching a match for the -regular expression), a \fIrange\fR (see below), ``.'' -(matching any single character), ``^'' (matching the null string at the -beginning of the input string), ``$'' (matching the null string at the -end of the input string), a ``\e'' followed by a single character (matching -that character), or a single character with no other significance -(matching that character). -.PP -A \fIrange\fR is a sequence of characters enclosed in ``[]''. -It normally matches any single character from the sequence. -If the sequence begins with ``^'', -it matches any single character \fInot\fR from the rest of the sequence. -If two characters in the sequence are separated by ``\-'', this is shorthand -for the full list of ASCII characters between them -(e.g. ``[0-9]'' matches any decimal digit). -To include a literal ``]'' in the sequence, make it the first character -(following a possible ``^''). -To include a literal ``\-'', make it the first or last character. - -.SH "CHOOSING AMONG ALTERNATIVE MATCHES" -.PP -In general there may be more than one way to match a regular expression -to an input string. For example, consider the command -.CS -\fBregexp (a*)b* aabaaabb x y\fR -.CE -Considering only the rules given so far, \fBx\fR and \fBy\fR could -end up with the values \fBaabb\fR and \fBaa\fR, \fBaaab\fR and \fBaaa\fR, -\fBab\fR and \fBa\fR, or any of several other combinations. -To resolve this potential ambiguity \fBregexp\fR chooses among -alternatives using the rule ``first then longest''. -In other words, it considers the possible matches in order working -from left to right across the input string and the pattern, and it -attempts to match longer pieces of the input string before shorter -ones. More specifically, the following rules apply in decreasing -order of priority: -.IP [1] -If a regular expression could match two different parts of an input string -then it will match the one that begins earliest. -.IP [2] -If a regular expression contains \fB|\fR operators then the leftmost -matching sub-expression is chosen. -.IP [3] -In \fB*\fR, \fB+\fR, and \fB?\fR constructs, longer matches are chosen -in preference to shorter ones. -.IP [4] -In sequences of expression components the components are considered -from left to right. -.LP -In the example from above, \fB(a*)b*\fR matches \fBaab\fR: the \fB(a*)\fR -portion of the pattern is matched first and it consumes the leading -\fBaa\fR; then the \fBb*\fR portion of the pattern consumes the -next \fBb\fR. Or, consider the following example: -.CS -\fBregexp (ab|a)(b*)c abc x y z\fR -.CE -After this command \fBx\fR will be \fBabc\fR, \fBy\fR will be -\fBab\fR, and \fBz\fR will be an empty string. -Rule 4 specifies that \fB(ab|a)\fR gets first shot at the input -string and Rule 2 specifies that the \fBab\fR sub-expression -is checked before the \fBa\fR sub-expression. -Thus the \fBb\fR has already been claimed before the \fB(b*)\fR -component is checked and \fB(b*)\fR must match an empty string. - -.SH KEYWORDS -match, regular expression, string |