Non-primitive to primitive cast in Rust?

user_9159340 0
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I'm trying to verify an IP address in Rust, but I can't find a solution casting a str into a u8 that doesn't involve using nightly Rust:

use std::net::{IpAddr, Ipv4Addr};

fn verify_address(address: String) -> bool {
    let v: Vec<&str> = address.split('.').collect();

    let v_u8: Vec<u8> = v.iter().map(|c| *c.to_owned() as u8).collect();

    let addr = IpAddr::V4(Ipv4Addr::new(v_u8[0], v_u8[1], v_u8[2], v_u8[3]));
        //.expect("ERR: Error parsing IPv4 address!");

    if !addr.is_ipv4()  {
        return false;
    }
    return true;
}

error[E0605]: non-primitive cast: `str` as `u8`
 --> src/lib.rs:6:42
  |
6 |     let v_u8: Vec<u8> = v.iter().map(|c| *c.to_owned() as u8).collect();
  |                                          ^^^^^^^^^^^^^^^^^^^
  |
  = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
rust type-conversion casting
1 Answers

Please reread the chapter about error handling. You do not need all this:

use std::net::Ipv4Addr;

fn main() {
    let ip = "127.0.0.1".parse::<Ipv4Addr>();

    match ip {
        Ok(ip) => println!("valid"),
        Err(e) => println!("invalid"),
    }
}

About your question, you can use primitive cast for... primitive types only. You must use From and Into, or parse if you convert a &str into another type.

user_44988310
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