Macro nom::preceded

macro_rules! preceded {
    ($i:expr, $submac:ident!( $($args:tt)* ), $submac2:ident!( $($args2:tt)* )) => { ... };
    ($i:expr, $submac:ident!( $($args:tt)* ), $g:expr) => { ... };
    ($i:expr, $f:expr, $submac:ident!( $($args:tt)* )) => { ... };
    ($i:expr, $f:expr, $g:expr) => { ... };
}

preceded!(I -> IResult<I,T>, I -> IResult<I,O>) => I -> IResult<I, O> preceded returns the result of its second parser if both succeed

named!(parser<&str, &str>, preceded!(char!('-'), alpha1));

assert_eq!(parser("-abc"), Ok(("", "abc")));
assert_eq!(parser("abc"), Err(Err::Error(("abc", ErrorKind::Char))));
assert_eq!(parser("-123"), Err(Err::Error(("123", ErrorKind::Alpha))));