nom::escaped_transform

macro_rules! escaped_transform {
    ($i:expr, $submac:ident!( $($args:tt)* ), $control_char: expr, $($rest:tt)+) => { ... };
    ($i:expr, $f:expr, $control_char: expr, $($rest:tt)+) => { ... };
}

escaped_transform!(&[T] -> IResult<&[T], &[T]>, T, &[T] -> IResult<&[T], &[T]>) => &[T] -> IResult<&[T], Vec<T>> matches a byte string with escaped characters.

The first argument matches the normal characters (it must not match the control character), the second argument is the control character (like \ in most languages), the third argument matches the escaped characters and trnasforms them.

As an example, the chain abc\tdef could be abc def (it also consumes the control character)

fn to_s(i:Vec<u8>) -> String {
  String::from_utf8_lossy(&i).into_owned()
}
 named!(transform < String >,
   map!(
     escaped_transform!(call!(alpha), '\\',
       alt!(
           tag!("\\")       => { |_| &b"\\"[..] }
         | tag!("\"")       => { |_| &b"\""[..] }
         | tag!("n")        => { |_| &b"\n"[..] }
       )
     ), to_s
   )
 );
 assert_eq!(transform(&b"ab\\\"cd"[..]), Done(&b""[..], String::from("ab\"cd")));