Method at_start

std/re/src/main/matcher.rs:239–241

(&self, pos: usize)

    }

    fn at_start(&self, pos: usize) -> bool {
        pos == 0 || (self.flags.multiline && pos > 0 && self.input[pos - 1] == '\n')
    }

    fn at_end(&self, pos: usize) -> bool {
        let len = self.input.len();