我有下面两个具体的ml中的表达式和声明语法，我不熟悉ml，所以我只是想知道是否有人能帮我把它转换成java，非常感谢

Exp::= 
       Ide |
       "if" Exp "then" Exp "else" Exp |
       "fun" "(" Ide ")" Exp |
       Exp "(" Exp ")" |
       "let" Decl "in" Exp |
       "(" Exp ")"

Decl ::=
       Ide "=" Exp | 
       Decl "then" Decl | 
       "rec" Decl | 
       "(" Decl ")"