@
([^\{\{]++|\{(?!\{))
|
\{\{(\w+)
(?: \s+ (\w+(?:=(?:"((?:\\\\\\\\|\\"|[^"]++)*)"|'((?:\\\\\\\\|\\'|[^']++|)*)'))? ) )*
\}\}
((?R)*)
\{\{/\g{-5}\}\}
|
\{\{(\w+)(?: \s+ (\w+(?:=(?:"((?:\\\\\\\\|\\"|[^"]++)*)"|'((?:\\\\\\\\|\\'|[^']++|)*)'))? )
)*\}\}
@
gmxs