Macro nom::escaped_transform

macro_rules! escaped_transform {
    ($i : expr, $submac1 : ident! ($($args : tt) *), $control_char : expr,
 $submac2 : ident! ($($args2 : tt) *)) => { ... };
    ($i : expr, $normal : expr, $control_char : expr, $submac2 : ident!
 ($($args2 : tt) *)) => { ... };
    ($i : expr, $submac1 : ident! ($($args : tt) *), $control_char : expr,
 $transform : expr) => { ... };
    ($i : expr, $normal : expr, $control_char : expr, $transform : expr) => { ... };
}

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 transforms them

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

Example

fn to_s(i:Vec<u8>) -> String {
  String::from_utf8_lossy(&i).into_owned()
}

 named!(transform < String >,
   map!(
     escaped_transform!(call!(alpha1), '\\',
       alt!(
           tag!("\\")       => { |_| &b"\\"[..] }
         | tag!("\"")       => { |_| &b"\""[..] }
         | tag!("n")        => { |_| &b"\n"[..] }
       )
     ), to_s
   )
 );
 assert_eq!(transform(&b"ab\\\"cd"[..]), Ok((&b""[..], String::from("ab\"cd"))));