⁉️Try-Statements

Try-statement syntax

try <expr> with <expr if error != nil>

--OR--

let <successVar, failureVar> = try <expr> with <expr>

The try-statement will evaluate the expression in-between try and with. Said expression must have a type of (..., error).

• If error != nil: the expression to the right of with will be returned.

• If error == nil:

  • If you're using the first syntax: Control flow will continue as normal

  • If you're using the second syntax: expression between try and with will be destructured into successVar and failureVar

Working Example

Gauntlet

package main

import "fmt" as fmt
import "errors" as errors

fun divide(num1: Int, num2: Int): (Int, Error) {
  if num2 == 0 {
    return (0, errors.new("Cannot divide by 0"))
  }
  return (num1 / num2, null)
}

fun divideBy2(num: Int): (Int, Error) {
  return divide(num, 2)
}

fun divideBy0(num: Int): (Int, Error) {
  return divide(num, 0) 
}

fun getResults(num: Int): (Int, Error) {
  let dBy2Res, dBy2Err = try divideBy2(5) with (dBy2Res, dBy2Err)
  let dBy0Res, dBy0Err = try divideBy0(10) with (dBy0Res, dBy0Err)
  return (dBy2Res + dBy0Res, null)
}

fun main(): Unit {
  fmt.println("Let's see if there's an error:")
  let res, err = getResults(10)
  fmt.println(err != null)
}

Transpiled

Output