Example of a Calendar using associative types

time.rs

struct Instant {
    nanos: i64,
}

trait ChronoUnit {
    fn convert_to_nanos(&self) -> i64;
    fn is_estimate(&self) -> bool;
    // get_estimate()
}

trait Calendar {
   type Sec : ChronoUnit;
   type Min : ChronoUnit;
   type Hrs : ChronoUnit;
   type Day : ChronoUnit;
   type Mon : ChronoUnit;
}

struct Second;
struct Minute;
struct Hour;
struct Day;
struct Month;

impl ChronoUnit for Second {
    fn convert_to_nanos(&self) -> i64 {
        1_000_000
    }
    fn is_estimate(&self) -> bool {
        false
    }
}

impl ChronoUnit for Minute {
    fn convert_to_nanos(&self) -> i64 {
        60_000_000
    }
    fn is_estimate(&self) -> bool {
        false
    }
}

impl ChronoUnit for Hour {
    fn convert_to_nanos(&self) -> i64 {
        3_600_000_000
    }
    fn is_estimate(&self) -> bool {
        false
    }
}


impl ChronoUnit for Day {
    fn convert_to_nanos(&self) -> i64 {
        86_400_000_000
    }
    fn is_estimate(&self) -> bool {
        false
    }
}

impl ChronoUnit for Month {
    fn convert_to_nanos(&self) -> i64 {
        0
    }
    fn is_estimate(&self) -> bool {
        true
    }
}


struct GregorianCalendar{
    inst: Instant
}

impl Calendar for GregorianCalendar {
   type Sec = Second;
   type Min = Minute;
   type Hrs = Hour;
   type Day = Day;
   type Mon = Month;
}// Add code here

fn main() {
    // Add code here
}