\r? keeppyz\n4Y\r?:i{BFgt>?|}tru e ,Y~z{BF\r>?|}fa ls e ,N#$A;
--p\rK ke | } fa ls e , Y\r?i&d e l(), keep\rp\rK eep \r66.\r\r\n G|}true.\rK(6~zFB|}false, ?K1¡¢£ ?\rp\r? w¤¥p\r¦-&§w¨©\n#$ª¦«¬s-¦aX®6\n\]|} \r?¯NULL °i?K4±²³´#$pE7\nkeep()Bµ¶\r?°\rip·¸&\nkeeppY¹3&? ?pº“»¼”PQ\n½¾¿Àkeepp\r¸Á wÃÄÅÆÇNULLµ¶Èp\r4.5 É Ê Ë (p re c e d e n c e )\rs-ÌÍÎÏÉÊËÐÑ\n??\rnonterm N {\r-> A B C precedence("+") { /*...*/ }\r}\r?6JÍ#V"N ->A B C"=@P`nÉÊËpÒÓÔRÕÖ\r×Øp\r4.6 forbid_next\rs-ÌÍ ?ÙÚÛ?FÜÝlookahead(forbidden lookahead),??\rnonterm N {\r-> A B C forbid_next("+") forbid_next("*") { /*...*/ }\r)\r?6ÞÍ#V"N -> A B C" 3F#$?K? ?`ß?“+"ÙÚ?“*\r67