Package listnewid4; Helpers tab = 9; cr = 13; lf = 10; eol = [[cr + lf] + [cr + lf]]; white = [[' ' + tab] + eol]; lowercase = ['a' .. 'z']; uppercase = ['A' .. 'Z']; letter = [uppercase + lowercase]; digit = ['0'..'9']; id_part = lowercase (lowercase | digit)*; blank = (' ' | tab | eol)+; Tokens tar = 'tar'; id = id_part ('_' id_part)*; minus = '-'; semicolon = ';'; letter = letter; l_bkt = '['; r_bkt = ']'; blank = blank; Ignored Tokens /* These tokens are simply ignored by the parser. */ blank; /*****************/ Productions grammar = P.tar semicolon {-> P.tar.first}; tar {-> [first]:grammar grammar*} = {first} T.tar [previous]:id [firstletter]:letter minus [first]:id letter id [otherletter]:letter {-> Null [ New grammar.first(previous, letter) New grammar.second(firstletter) New grammar.third(id, minus, otherletter) ] }; Abstract Syntax Tree grammar = {first} id letter | {second} letter | {third} id minus letter ;