fn skip_while(&mut self, mut keep_going: impl FnMut(char) -> bool) {
        while self.peek().map_or(false, |ch| keep_going(ch)) {
            self.advance();
        }
    }
/// Skip characters while the predicate matches the lookahead character.
Skip characters while the predicate matches the lookahead character.
Skip characters while the predicate matches the lookahead character .
fn skip_while(&mut self, mut keep_going: impl FnMut(char) -> bool) {
        while self.peek().map_or(false, |ch| keep_going(ch)) {
            self.advance();
        }
    }
fn skip_while ( & mut self , mut keep_going : impl FnMut ( char ) -> bool ) { while self . peek ( ) . map_or ( false , | ch | keep_going ( ch ) ) { self . advance ( ) ; } }
Skip characters while the predicate matches the lookahead character.
Skip characters while the predicate matches the lookahead character .
&mut self
keep_going
impl FnMut(char) -> bool
&mut self
keep_going
impl FnMut(char) -> bool