validUnderscores

pub fn validUnderscores(s: []const u8, comptime base: u8) bool {
    var i: usize = 0;
    while (i < s.len) : (i += 1) {
        if (s[i] == '_') {
            // underscore at start of end
            if (i == 0 or i + 1 == s.len) {
                return false;
            }
            // consecutive underscores
            if (!common.isDigit(s[i - 1], base) or !common.isDigit(s[i + 1], base)) {
                return false;
            }

            // next is guaranteed a digit, skip an extra
            i += 1;
        }
    }

    return true;
}