use strict;
my $str = '<!-- test -->
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">
<html goat:style="\'\'inva\'lid css I know">textttt<head></head><body><div class="onfoodstamps"><div class="upper">foo<p>ayyy</p>bar</div>baz</div><br/></head></html>';
my $regex = qr/(?(DEFINE)
(?<XHTML>
(?&comment)*\s*
(?&DOCTYPE)
(?&comment)*\s*
(?&HTML)
(?&comment)*\s*
)
# HTML element
(?<HTML>
<html(?&attrs)?>(?&content)<\/html>
)
# Match content
(?<content>
\s*
(?:
((?&tag) | [^<>]+)\s*
)*
)
# General tag
(?<tag>
<((?&tagname))(?&attrs)?\s*(?:
\/>|
>\s*(?&content)\s*
<\/\g'-1'>
)|(?&comment)
)
# Attributes
(?<attrs>\s+
# The name
(?&keyword) (
\s*=\s*
(?:
(?&keyword)|(?&string)
)
)?
(?&attrs)?
)
(?<string>
"(?:\\.|.)+?"|
'(?:\\.|.)+?'
)
(?<comment>
\s*<!--(.+?)-->\s*
)
# Match keyword
(?<keyword>[^\s\/>"'=]+)
# Match tag name
(?<tagname>(?!xml)[A-Za-z_][A-Za-z\d_.-]*)
# DOCTYPE expression
(?<DOCTYPE>
<!doctype\s+x?html\s*(public\s*(?&string))?(\s+(?&string))*>
)
)
^\s*(?&XHTML)\s*$/xisp;
if ( $str =~ /$regex/g ) {
print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n";
# print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n";
# print "Capture Group 2 is $2 ... and so on\n";
}
# ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p'
# Named capture groups can be called via $+{name}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html