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))));