In Rust, how do I use implemented trait FromStr on BigInt?

Question

I am trying to get this program to compile:

extern crate num;
use num::bigint::BigInt;
use std::from_str::FromStr;

fn main () {
    println!(\"{}\", BigInt:         


        

Answer 1

The plain function from_str has been removed in recent versions of Rust. This function is now only available as a method of the FromStr trait.

The modern way to parse values is the .parse method of str:

extern crate num;
use num::bigint::BigInt;

fn main() {
    match "1".parse::() {
        Ok(n)  => println!("{}", n),
        Err(_) => println!("Error")
    }
}