/// Checks if the next char to be consumed matches a user-given condition.
Checks if the next char to be consumed matches a user-given condition.
Checks if the next char to be consumed matches a user - given condition .
fn peek_match(&self, f: impl FnOnce(char) -> bool) -> bool {
        match self.peek() {
            Some(ch) => f(ch),
            None => false,
        }
    }
fn peek_match ( & self , f : impl FnOnce ( char ) -> bool ) -> bool { match self . peek ( ) { Some ( ch ) => f ( ch ) , None => false , } }
Checks if the next char to be consumed matches a user-given condition.
Checks if the next char to be consumed matches a user - given condition .
&self
f
impl FnOnce(char) -> bool