示例宣告
infixr 5 ++infixl 4 <*>, <*, *>, <**>infixl 8 `shift`, `rotate`, `shiftL`, `shiftR`, `rotateL`, `rotateR`infix 4 ==, /=, <, <=, >=, >infix ??
infixr 5 ++infixl 4 <*>, <*, *>, <**>infixl 8 `shift`, `rotate`, `shiftL`, `shiftR`, `rotateL`, `rotateR` infix 4 ==, /=, <, <=, >=, >infix ??