$switchable = qr/foo|quux|glarf|boojum/;
$name = qr/[^\s<>=]+/; # broader than the XML Spec, but that's OK
$attValue = qr/(?:'[^'<>]*'|"[^"<>]*")/;
$attribute = qr/(?:\s+(?>$name)\s*=\s*(?>$attValue))/;

		s/
			^
			<
				($switchable)
				($attribute*?)
				# get the value of the type attribute
					(\s+)
					type
					(\s*=\s*)
					(['"]) # either quote allowable
					# but then the other quote char
					# or just about anything else
					# is allowed inside ...
					# minimal match for efficiency
					((?(?<=')[^']*?|[^"]*?)) 
					\5 # matching close quote
				($attribute*?)
				(\s*)
			>
			(.*) # what's between tags, even newline
			<\/
				\1 # matching end tag
				(\s*)
			>
			$
		/<!--switch--><$6$2$3metaType$4$5$1$5$7$8>$9<\/$6$10>/sox