将表达式的具体语法从ML转换为Java

Question

我在ML中有以下2个表达式和声明的具体语法，我不熟悉ML，所以我只是想知道是否有人可以帮我用Java转换它，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 ")"