/ 
Regexp-Wildcards-0.08
River stage one • 2 direct dependents • 8 total dependents
/ Regexp::Wildcards

NAME

Regexp::Wildcards - Converts wildcard expressions to Perl regular expressions.

VERSION

Version 0.08

SYNOPSIS

use Regexp::Wildcards qw/wc2re/;

my $re;
$re = wc2re 'a{b?,c}*' => 'unix';   # Do it Unix style.
$re = wc2re 'a?,b*'    => 'win32';  # Do it Windows style.
$re = wc2re '*{x,y}?'  => 'jokers'; # Process the jokers & escape the rest.
$re = wc2re '%a_c%'    => 'sql';    # Turn SQL wildcards into regexps.

DESCRIPTION

In many situations, users may want to specify patterns to match but don't need the full power of regexps. Wildcards make one of those sets of simplified rules. This module converts wildcard expressions to Perl regular expressions, so that you can use them for matching. It handles the * and ? shell jokers, as well as Unix bracketed alternatives {,}, but also % and _ SQL wildcards. Backspace (\) is used as an escape character. Wrappers are provided to mimic the behaviour of Windows and Unix shells.

VARIABLES

These variables control if the wildcards jokers and brackets must capture their match. They can be globally set by writing in your program

$Regexp::Wildcards::CaptureSingle = 1;
# From then, "exactly one" wildcards are capturing

or can be locally specified via local

{
 local $Regexp::Wildcards::CaptureSingle = 1;
 # In this block, "exactly one" wildcards are capturing.
 ...
}
# Back to the situation from before the block

This section describes also how those elements are translated by the functions.

$CaptureSingle

When this variable is true, each occurence of unescaped "exactly one" wildcards (i.e. ? jokers or _ for SQL wildcards) are made capturing in the resulting regexp (they are be replaced by (.)). Otherwise, they are just replaced by .. Default is the latter.

For jokers :
'a???b\\??' is translated to 'a(.)(.)(.)b\\?(.)' if $CaptureSingle is true
                             'a...b\\?.'         otherwise (default)

For SQL wildcards :
'a___b\\__' is translated to 'a(.)(.)(.)b\\_(.)' if $CaptureSingle is true
                             'a...b\\_.'         otherwise (default)

$CaptureAny

By default this variable is false, and successions of unescaped "any" wildcards (i.e. * jokers or % for SQL wildcards) are replaced by one single .*. When it evalutes to true, those sequences of "any" wildcards are made into one capture, which is greedy ((.*)) for $CaptureAny > 0 and otherwise non-greedy ((.*?)).

For jokers :
'a***b\\**' is translated to 'a.*b\\*.*'       if $CaptureAny is false (default)
                             'a(.*)b\\*(.*)'   if $CaptureAny > 0
                             'a(.*?)b\\*(.*?)' otherwise

For SQL wildcards :
'a%%%b\\%%' is translated to 'a.*b\\%.*'       if $CaptureAny is false (default)
                             'a(.*)b\\%(.*)'   if $CaptureAny > 0
                             'a(.*?)b\\%(.*?)' otherwise

$CaptureBrackets

If this variable is set to true, valid brackets constructs are made into ( | ) captures, and otherwise they are replaced by non-capturing alternations ((?: | )), which is the default.

'a{b\\},\\{c}' is translated to 'a(b\\}|\\{c)'   if $CaptureBrackets is true
                                'a(?:b\\}|\\{c)' otherwise (default)

FUNCTIONS

wc2re_jokers

This function takes as its only argument the wildcard string to process, and returns the corresponding regular expression where the jokers ? ("exactly one") and * ("any") have been translated into their regexp equivalents (see "VARIABLES" for more details). All other unprotected regexp metacharacters are escaped.

# Everything is escaped.
print 'ok' if wc2re_jokers('{a{b,c}d,e}') eq '\\{a\\{b\\,c\\}d\\,e\\}';

wc2re_sql

Similar to the precedent, but for the SQL wildcards _ ("exactly one") and % ("any"). All other unprotected regexp metacharacters are escaped.

wc2re_unix

This function conforms to standard Unix shell wildcard rules. It successively escapes all unprotected regexp special characters that doesn't hold any meaning for wildcards, turns ? and * jokers into their regexp equivalents (see "wc2re_jokers"), and changes bracketed blocks into (possibly capturing) alternations as described in "VARIABLES". If brackets are unbalanced, it tries to substitute as many of them as possible, and then escape the remaining { and }. Commas outside of any bracket-delimited block are also escaped.

# This is a valid bracket expression, and is completely translated.
print 'ok' if wc2re_unix('{a{b,c}d,e}') eq '(?:a(?:b|c)d|e)';

The function handles unbalanced bracket expressions, by escaping everything it can't recognize. For example :

# The first comma is replaced, and the remaining brackets and comma are escaped.
print 'ok' if wc2re_unix('{a\\{b,c}d,e}') eq '(?:a\\{b|c)d\\,e\\}';

# All the brackets and commas are escaped.
print 'ok' if wc2re_unix('{a{b,c\\}d,e}') eq '\\{a\\{b\\,c\\}d\\,e\\}';

wc2re_win32

This one works just like the one before, but for Windows wildcards. Bracketed blocks are no longer handled (which means that brackets are escaped), but you can provide a comma-separated list of items.

# All the brackets are escaped, and commas are seen as list delimiters.
print 'ok' if wc2re_win32('{a{b,c}d,e}') eq '(?:\\{a\\{b|c\\}d|e\\})';

wc2re

A generic function that wraps around all the different rules. The first argument is the wildcard expression, and the second one is the type of rules to apply which can be :

'unix', 'win32', 'jokers', 'sql'

For one of those raw rule names, wc2re simply maps to wc2re_unix, wc2re_win32, wc2re_jokers and wc2re_sql respectively.

$^O

If you supply the Perl operating system name, the call is deferred to wc2re_win32 for $^O equal to 'dos', 'os2', 'MSWin32' or 'cygwin', and to wc2re_unix in all the other cases.

If the type is undefined or not supported, it defaults to 'unix'.

# Wraps to wc2re_jokers ($re eq 'a\\{b\\,c\\}.*').
$re = wc2re 'a{b,c}*' => 'jokers';

# Wraps to wc2re_win32 ($re eq '(?:a\\{b|c\\}.*)')
#       or wc2re_unix  ($re eq 'a(?:b|c).*')       depending on $^O.
$re = wc2re 'a{b,c}*' => $^O;

EXPORT

These five functions are exported only on request : wc2re, wc2re_unix, wc2re_win32, wc2re_jokers and wc2re_sql. The variables are not exported.

DEPENDENCIES

Text::Balanced, which is bundled with perl since version 5.7.3

CAVEATS

This module does not implement the strange behaviours of Windows shell that result from the special handling of the three last characters (for the file extension). For example, Windows XP shell matches *a like .*a, *a? like .*a.?, *a?? like .*a.{0,2} and so on.

SEE ALSO

Some modules provide incomplete alternatives as helper functions :

Net::FTPServer has a method for that. Only jokers are translated, and escaping won't preserve them.

File::Find::Match::Util has a wildcard function that compiles a matcher. It only handles *.

Text::Buffer has the convertWildcardToRegex class method that handles jokers.

AUTHOR

Vincent Pit, <perl at profvince.com>, http://www.profvince.com.

You can contact me by mail or on #perl @ FreeNode (vincent or Prof_Vince).

BUGS

Please report any bugs or feature requests to bug-regexp-wildcards at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Regexp-Wildcards. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc Regexp::Wildcards

COPYRIGHT & LICENSE

Copyright 2007-2008 Vincent Pit, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.