rust源代码 ch5/src/state/arith_ops.rs pub arith 函数有不懂的地方可否解答？

[123zmz123]

No description provided.

[123zmz123]

请问作者，我知道x y 是pattern variable， 但是为何传入的时候要加*号，个人能力有限找遍了rust文档没有定位到答案，谢谢

[zxh0]

你好。可以试着去掉*，编译一下，看看编译错误应该就理解了：

$ cargo build
   Compiling ch05 v0.1.0 (luago-book/code/rust/ch05)
error[E0308]: mismatched types
   --> src/state/arith_ops.rs:104:55
    |
104 |                     return Some(LuaValue::Integer(iop(x, y)));
    |                                                       ^
    |                                                       |
    |                                                       expected `i64`, found `&i64`
    |                                                       help: consider dereferencing the borrow: `*x`

error[E0308]: mismatched types
   --> src/state/arith_ops.rs:104:58
    |
104 |                     return Some(LuaValue::Integer(iop(x, y)));
    |                                                          ^
    |                                                          |
    |                                                          expected `i64`, found `&i64`
    |                                                          help: consider dereferencing the borrow: `*y`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0308`.
error: could not compile `ch05`

To learn more, run the command again with --verbose.

[123zmz123]

谢谢提醒😃