pub fn parse_next_substitution(s: &str) -> Option<(Substitution<'_>, &str)> {
        let at = {
            let start = s.find('$')?;
            match s[start + 1..].chars().next()? {
                '$' => return Some((Substitution::Escape((start, start + 2)), &s[start + 2..])),
                c @ '0'..='9' => {
                    let n = (c as u8) - b'0';
                    return Some((Substitution::Ordinal(n, (start, start + 2)), &s[start + 2..]));
                }
                _ => { /* fall-through */ }
            }

            Cur::new_at(s, start)
        };

        let at = at.at_next_cp()?;
        let (c, inner) = at.next_cp()?;

        if !is_ident_head(c) {
            None
        } else {
            let end = at_next_cp_while(inner, is_ident_tail);
            let slice = at.slice_between(end).unwrap();
            let start = at.at - 1;
            let end_pos = at.at + slice.len();
            Some((Substitution::Name(slice, (start, end_pos)), end.slice_after()))
        }
    }
/// Parse the next substitution from the input string.
Parse the next substitution from the input string.
Parse the next substitution from the input string .
pub fn parse_next_substitution(s: &str) -> Option<(Substitution<'_>, &str)> {
        let at = {
            let start = s.find('$')?;
            match s[start + 1..].chars().next()? {
                '$' => return Some((Substitution::Escape((start, start + 2)), &s[start + 2..])),
                c @ '0'..='9' => {
                    let n = (c as u8) - b'0';
                    return Some((Substitution::Ordinal(n, (start, start + 2)), &s[start + 2..]));
                }
                _ => { /* fall-through */ }
            }
            Cur::new_at(s, start)
        };
        let at = at.at_next_cp()?;
        let (c, inner) = at.next_cp()?;
        if !is_ident_head(c) {
            None
        } else {
            let end = at_next_cp_while(inner, is_ident_tail);
            let slice = at.slice_between(end).unwrap();
            let start = at.at - 1;
            let end_pos = at.at + slice.len();
            Some((Substitution::Name(slice, (start, end_pos)), end.slice_after()))
        }
    }
pub fn parse_next_substitution ( s : & str ) -> Option < ( Substitution < ' _ > , & str ) > { let at = { let start = s . find ( '$' ) ? ; match s [ start + 1 .. ] . chars ( ) . next ( ) ? { '$' => return Some ( ( Substitution :: Escape ( ( start , start + 2 ) ) , & s [ start + 2 .. ] ) ) , c @ '0' ..= '9' => { let n = ( c as u8 ) - b'0' ; return Some ( ( Substitution :: Ordinal ( n , ( start , start + 2 ) ) , & s [ start + 2 .. ] ) ) ; } _ => { /* fall-through */ } } Cur :: new_at ( s , start ) } ; let at = at . at_next_cp ( ) ? ; let ( c , inner ) = at . next_cp ( ) ? ; if ! is_ident_head ( c ) { None } else { let end = at_next_cp_while ( inner , is_ident_tail ) ; let slice = at . slice_between ( end ) . unwrap ( ) ; let start = at . at - 1 ; let end_pos = at . at + slice . len ( ) ; Some ( ( Substitution :: Name ( slice , ( start , end_pos ) ) , end . slice_after ( ) ) ) } }
Parse the next substitution from the input string.
Parse the next substitution from the input string .
s
&str
s
&str