chrono_coercion.rs

chrono_coercion.rs

use chrono::{DateTime, Local, Duration};
use std::ops::Deref;

struct Meeting {
    name: String,
    start_time: DateTime<Local>,
}

impl Deref for Meeting {
    type Target = DateTime<Local>;

    fn deref(&self) -> &Self::Target {
        &self.start_time
    }
}

fn main() {
    let project_kickoff = Meeting {
        name: String::from("Project Kickoff"),
        start_time: Local::now(),
    };

    println!("--- Meeting Details ---");
    println!("Meeting Name: {}", project_kickoff.name);
    println!("Start Time:   {}", project_kickoff.format("%Y-%m-%d %H:%M:%S"));

    // Passes &Meeting, which successfully coerces into &DateTime<Local>
    print_days_until_deadline(&project_kickoff);
}

fn print_days_until_deadline(current_time: &DateTime<Local>) {
    // Add the asterisk '*' to dereference the pointer explicitly
    let deadline = *current_time + Duration::days(7);
    println!("Deadline:     {}", deadline.format("%A, %B %d"));
}

https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=cedc3bb3d7a903aa37b2010428176bff