Macro futures_await_synom::value

macro_rules! value {
    ($i:expr, $res:expr) => { ... };
}

Produce the given value without parsing anything. Useful as an argument to switch!.

• Syntax: value!(VALUE)
• Output: VALUE

extern crate syn;
#[macro_use] extern crate synom;

use syn::{Ident, Ty};
use synom::tokens::*;

#[derive(Debug)]
enum UnitType {
    Struct {
        name: Ident,
    },
    Enum {
        name: Ident,
        variant: Ident,
    },
}

// Parse a unit struct or enum: either `struct S;` or `enum E { V }`.
named!(unit_type -> UnitType, do_parse!(
    which: alt!(
        syn!(Struct) => { |_| 0 }
        |
        syn!(Enum) => { |_| 1 }
    ) >>
    id: syn!(Ident) >>
    item: switch!(value!(which),
        0 => map!(
            syn!(Semi),
            move |_| UnitType::Struct {
                name: id,
            }
        )
        |
        1 => map!(
            braces!(syn!(Ident)),
            move |(variant, _)| UnitType::Enum {
                name: id,
                variant: variant,
            }
        )
    ) >>
    (item)
));