Function escaped_transform

pub fn escaped_transform<I, Error, F, G, O1, O2, ExtendItem, Output>(
    normal: F,
    control_char: char,
    transform: G,
) -> impl FnMut(I) -> IResult<I, Output, Error>
where
    I: Clone + Offset + Input + ExtendInto<Item = ExtendItem, Extender = Output>,
    O1: ExtendInto<Item = ExtendItem, Extender = Output>,
    O2: ExtendInto<Item = ExtendItem, Extender = Output>,
    <I as Input>::Item: AsChar,
    F: Parser<I, Output = O1, Error = Error>,
    G: Parser<I, Output = O2, Error = Error>,
    Error: ParseError<I>,

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)

use nom::bytes::complete::{escaped_transform, tag};
use nom::character::complete::alpha1;
use nom::branch::alt;
use nom::combinator::value;

fn parser(input: &str) -> IResult<&str, String> {
  escaped_transform(
    alpha1,
    '\\',
    alt((
      value("\\", tag("\\")),
      value("\"", tag("\"")),
      value("\n", tag("n")),
    ))
  )(input)
}

assert_eq!(parser("ab\\\"cd"), Ok(("", String::from("ab\"cd"))));
assert_eq!(parser("ab\\ncd"), Ok(("", String::from("ab\ncd"))));