CODEWITHSUNDEEP
rust
Maik Klein
Maik Klein

Reputation: 16158

Creating a macro with infinte arguments

struct Foo{
    value: i32
}
impl Foo{
    fn get_and_change_value(&mut self) -> i32{
        let v = self.value;
        self.value = 42;
        v
    }
}
//glue_code_macro
fn main(){
let mut f1 = Foo{value:1};
let mut f2 = Foo{value:2};
let mut f3 = Foo{value:3};
let v: Vec<i32> = glue_code_macro!(f1,f2,f3);
}

I want to create the glue_code_macro which takes n variables and creates a vector. I don't think that I can achieve this with a normal function because I have a mutable reference and I would be unable to change its content.

In my head it would expand to

let v = {
  let v1 = f1.get_and_change_value();
  let v2 = f2.get_and_change_value();
  let v3 = f3.get_and_change_value();
  vec!(v1,v2,v3)
}

Is this possible? If yes how would I do this?

Upvotes: 2

Views: 96

Answers (1)

A.B.
A.B.

Reputation: 16660

It's possible. Add this to the top of your module:

#![feature(macro_rules)]
macro_rules! glue_code_macro(
    ($($element:ident),*) => (
        vec![$($element.get_and_change_value(),)*]
    )
)

The macro guide explains how it works: http://doc.rust-lang.org/guide-macros.html

Upvotes: 3

Related Questions