::= 字母 { 字母 | 数字 } ::= 数字 { 数字 } ::= + | - | *| / | ( | ) | [ | ] | ; | . | | = | EOF | 空白字符 ::= : = ::= { ::= } ::= ′ ::= .. ::= a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t |u | v | w | x | y |z | A| B | C | D | E | F | G | H | I | J | K | L |M | N | O | P | Q | R | S | T | U |V | W | X| Y | Z ::= 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
