Something
public c v1 · immutablemax_day = (m == 2) * 28 + ((m % 2) * (m < 8) + ((m + 1) % 2) * (m >= 8)) * 31 + (((m + 1) % 2) * (m != 2) * (m < 8) + (m % 2) * (m >= 8)) * 30 + (m == 2) * (y % 4) * (!(y % 400))max_day = (m == 2) * 28 + ((m % 2) * (m < 8) + ((m + 1) % 2) * (m >= 8)) * 31 + (((m + 1) % 2) * (m != 2) * (m < 8) + (m % 2) * (m >= 8)) * 30 + (m == 2) * (y % 4) * (!(y % 400))