ziglings/exercises/021_errors.zig

//
// Believe it or not, sometimes things go wrong in programs.
//
// In Zig, an error is a value. Errors are named so we can identify
// things that can go wrong. Errors are created in "error sets", which
// are just a collection of named errors.
//
// We have the start of an error set, but we're missing the condition
// "TooSmall". Please add it where needed!
const MyNumberError = error{
  TooBig,
  TooSmall,
  TooFour,
};

const std = @import("std");

pub fn main() void {
  const nums = [_]u8{ 2, 3, 4, 5, 6 };
  
  for(nums) |n|{
    std.debug.print("{}", .{n});
    
    const number_error = numberFail(n);
    
    if(number_error == MyNumberError.TooBig){
      std.debug.print(">4. ", .{});
    }
    if(number_error == MyNumberError.TooSmall){
      std.debug.print("<4. ", .{});
    }
    if(number_error == MyNumberError.TooFour){
      std.debug.print("=4. ", .{});
    }
  }
  
  std.debug.print("\n", .{});
}

// Notice how this function can return any member of the MyNumberError
// error set.
fn numberFail(n: u8) MyNumberError{
  if(n > 4){ return MyNumberError.TooBig; }
  if(n < 4){ return MyNumberError.TooSmall; } // <---- this one is free!
  return MyNumberError.TooFour;
}