extern crate paste;

// Macro in item position: at module scope or inside of an impl block.
paste::item! {
    // Defines a const called `QRST`.
    const [<Q R S T>]: &str = "success!";
}

fn main() {
    // Macro in expression position: inside a function body.
    assert_eq!(
        paste::expr! { [<Q R S T>].len() },
        8,
    );
}

extern crate paste;

const ROUTE_A: &str = "/a";
const ROUTE_B: &str = "/b";

macro_rules! routes {
    ($($route:ident),*) => {{
        paste::expr! {
            vec![$( [<ROUTE_ $route>] ),*]
        }
    }}
}

fn main() {
    let routes = routes!(A, B);
    assert_eq!(routes, vec!["/a", "/b"]);
}

extern crate paste;

macro_rules! make_a_struct_and_getters {
    ($name:ident { $($field:ident),* }) => {
        // Define a struct. This expands to:
        //
        //     pub struct S {
        //         a: String,
        //         b: String,
        //         c: String,
        //     }
        pub struct $name {
            $(
                $field: String,
            )*
        }

        // Build an impl block with getters. This expands to:
        //
        //     impl S {
        //         pub fn get_a(&self) -> &str { &self.a }
        //         pub fn get_b(&self) -> &str { &self.b }
        //         pub fn get_c(&self) -> &str { &self.c }
        //     }
        paste::item! {
            impl $name {
                $(
                    pub fn [<get_ $field>](&self) -> &str {
                        &self.$field
                    }
                )*
            }
        }
    }
}

make_a_struct_and_getters!(S { a, b, c });

fn call_some_getters(s: &S) -> bool {
    s.get_a() == s.get_b() && s.get_c().is_empty()
}