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) != 0)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) != 0)