function - 使用 rust macro_rules 调用生成函数参数

Question

是否可以在参数位置通过宏调用生成函数参数？这就是我想要实现的目标：

macro_rules! deffn {
    (@test-param) => {
        test: String,
    };
    () => {
        fn new(
            // I need to generated the parameters inside this function (using a macro call)
            deffn!(@test-param)
        ) {
            println!("It works");
        }
    }
}
deffn!();

这是我从编译器得到的输出：

error: expected one of `:` or `|`, found `)`
   --> glib/src/param_spec.rs:392:15
    |
392 |           fn new(
    |  _______________^
393 | |             // I need to generated the parameters inside this function (using a macro call)
394 | |             deffn!(@test-param)
    | |                                - expected one of `:` or `|`
395 | |         ) {
    | |_________^ unexpected token
...
400 |   deffn!();
    |   -------- in this macro invocation
    |
    = note: anonymous parameters are removed in the 2018 edition (see RFC 1685)
    = note: this error originates in the macro `deffn` (in Nightly builds, run with -Z macro-backtrace for more info)
help: explicitly ignore the parameter name
    |
394 |             _: deffn!(@ test - param)
    |