Integer Operations with ard/int

The ard/int module provides functions for converting and parsing integers.

The int module provides:

String parsing to convert strings to integers
Error handling with Maybe types for failed conversions

use ard/int

fn main() {
  let num = Int::from_str("42").or(0)
}

API

`fn from_str(str: Str) Int?`

Parse a string into an integer. Returns a Maybe type - some if parsing succeeds, none if it fails.

use ard/int

let num = Int::from_str("42")
match num {
  val => io::print(val.to_str()),
  _ => io::print("Failed to parse")
}

Examples

Parse Integer from User Input

use ard/int
use ard/io

fn main() {
  io::print("Enter a number: ")
  let input = io::read_line().expect("Failed to read")

  match Int::from_str(input) {
    val => io::print("You entered: {val.to_str()}"),
    _ => io::print("Invalid integer")
  }
}

Use with Default Value

use ard/int

fn main() {
  let age = Int::from_str("thirty").or(18)
  // age is 18 since parsing failed
}

Validate User Input

use ard/int
use ard/io

fn main() {
  io::print("Enter age (1-120): ")
  let input = io::read_line().expect("Failed to read")

  match Int::from_str(input) {
    age => {
      if age >= 1 and age <= 120 {
        io::print("Valid age: {age.to_str()}")
      } else {
        io::print("Age out of valid range")
      }
    },
    _ => io::print("Invalid integer")
  }
}