lpeg = require "lpeg"
local P, S, R, B = lpeg.P, lpeg.S, lpeg.R, lpeg.B -- lpeg functions

Artist, Title, Album = "", "", "" 	-- return values

function CARTIST(s) Artist = s end	-- capture Artist
function CTITLE(s) Title = s end		-- capture Title
function CALBUM(s) Album = s end 		-- capture Abum

-- LPEG Pattern
-- global lpeg pattern
DELIMITER 		= P" - " 																							-- space minus space
DELIMITER2 		= P" / " 																							-- space slash space
ALL						= P(1)
FALLBACK			= ((ALL - DELIMITER)^1 / CARTIST) * DELIMITER * 			-- Artist
								(((ALL - DELIMITER2)^1 / CALBUM) * DELIMITER2)^-1 * -- Album
								(ALL / CTITLE) 																			-- Titel

-- stream spezific lpeg pattern					
PREJUNK				= P"Sie hören jetzt: " +
								P"we are playing now: "
POSTJUNK 			= DELIMITER + 
								DELIMITER2 + 
								P"'" * R"09"^1 + 
								P"[" * (1 - P"]")^0 * P"]"
PATTERN				= PREJUNK^0 * 
								((ALL - DELIMITER)^1 / CARTIST) * DELIMITER * 
								(((ALL - DELIMITER2)^1 / CALBUM) * DELIMITER2)^-1 * 
								((ALL - POSTJUNK)^1 / CTITLE)
-- end stream spezific lpeg pattern								

-- program body
--
line = io.read("*l")
if PATTERN:match(line) or FALLBACK:match(line) then
	io.write("Artist: ".. Artist .. "\n")
	io.write("Title : ".. Title .. "\n")
	io.write("Album : ".. Album .."\n")
else
  print("no match.")
end