#! perl -slw
use strict;
require 5.008;

my $re_quoted = qr[
	(["']) 										#'"
	(?{ local $q = $^N })
	(
		(??{
			"(?x:
				[^$q]
				|
				(?: (?<!$q)(?: (?: $q ){2} )+ )
				|
				(?: \\$q )
			)+"
		})
	)
	(?{ $quoted = $^N })
	(??{ "$q" })
]x;

while( <DATA> ){
	chomp;
	our $quoted;
	print;
	print "\t<$quoted>" while m[$re_quoted]g;
	print '';
}

__DATA__
unquoted stuff "quoted stuff" unquoted stuff
unquoted stuff 'quoted stuff' unquoted stuff
unquoted stuff "quoted stuff with embedded 'alternate' quotes" unquoted stuff
unquoted stuff 'quoted stuff with embedded "alternate" quotes' unquoted stuff
unquoted stuff "quoted stuff with embedded ""like"" quotes" unquoted stuff
unquoted stuff 'quoted stuff with embedded ''like'' quotes' unquoted stuff
unquoted stuff "quoted stuff with embedded """"like"""" quotes" unquoted stuff
unquoted stuff 'quoted stuff with embedded ''''like'''' quotes' unquoted stuff
unquoted stuff "quoted 'stuff' with escaped \"like\" quotes" unquoted stuff
unquoted stuff 'quoted 'stuff' with escaped \'like\' quotes' unquoted stuff
unquoted stuff "quoted stuff with embedded ""like"" quotes and escaped \"like\" quotes" unquoted stuff
unquoted stuff 'quoted stuff with embedded ''like'' quotes and escaped \'like\' quotes' unquoted stuff