Optional<T>(Standardlibrary/ErrorHandleing)

Optional is a type that is part of the standard library. that can hold either a value of type T or nothing (Null).

The Optional type Can be used like so.

int? MayBeNull = Null;
Optional<int> MayBeNull2 = Null;

Both being equivalent.

The Optional is an enum and here its implementation.

$Optional<T>:
 Opt(T opt),
 Null

The Optional type allows you to have

• Optional struct fields
• Optional function arguments
• Nullable pointers
• default values

|divide[float numerator,float denominator] -> float?:
  if denominator == 0:
    ret Null;
  else:
    ret Opt(numerator / denominator);

|main[]:
  var result = divide(2.0, 3.0);
 
  match result:
    Opt(out x):Fmt::Print("Result: {x}"),
    Null:Fmt::Print("Cannot divide by 0"),

Question Mark Operator,

The question mark operator, ? allows for easier use of the optional type.

It lets.

|AddLastNumbers[int[]& stack] -> int?:
    var a = stack.Pop();
    var b = stack.Pop();

    if Opt(a,out vala) && Opt(b,out valb):
      ret Opt(vala + valb);

    ret Null;

To become.

|AddLastNumbers[int[]& stack] -> int?:
  ret Opt((?stack.Pop()) + (?stack.Pop()))

When starting an expression with ? UCodeLang will check if its Null and will do an early return if it is.

makeing your life easier.

Notes

All Examples is taken from Rust as UCodeLang was directly inspired by the Rust Programming Language.