Macro wast::custom_reserved
source · [−]macro_rules! custom_reserved {
($name:ident) => { ... };
($name:ident = $rsv:expr) => { ... };
}
Expand description
A macro for defining custom reserved symbols.
This is like custom_keyword!
but for reserved symbols (Token::Reserved
)
instead of keywords (Token::Keyword
).
use wast::parser::{Parser, Result, Parse};
// Define a custom reserved symbol, the "spaceship" operator: `<=>`.
wast::custom_reserved!(spaceship = "<=>");
/// A "three-way comparison" like `(<=> a b)` that returns -1 if `a` is less
/// than `b`, 0 if they're equal, and 1 if `a` is greater than `b`.
struct ThreeWayComparison<'a> {
lhs: wast::Expression<'a>,
rhs: wast::Expression<'a>,
}
impl<'a> Parse<'a> for ThreeWayComparison<'a> {
fn parse(parser: Parser<'a>) -> Result<Self> {
parser.parse::<spaceship>()?;
let lhs = parser.parse()?;
let rhs = parser.parse()?;
Ok(ThreeWayComparison { lhs, rhs })
}
}