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Error Handling

Arden provides robust error handling using the Option<T> and Result<T, E> types.

Option

Represents a value that might be present or missing.

enum Option<T> {
    Some(T),
    None
}

Usage:

function findParams(id: Integer): Option<String> {
    if (id == 0) {
        return Option.None;
    }
    return Option.Some("Param");
}

Option Methods

  • is_some(): Boolean - Returns true if the option is a Some value.
  • is_none(): Boolean - Returns true if the option is a None value.
  • unwrap(): T - Returns the inner value or panics if None.

Result<T, E>

Represents a success (Ok) or failure (Error).

enum Result<T, E> {
    Ok(T),
    Error(E)
}

Usage:

function divide(a: Integer, b: Integer): Result<Integer, String> {
    if (b == 0) {
        return Result.Error("Division by zero");
    }
    return Result.Ok(a / b);
}

Result Methods

  • is_ok(): Boolean - Returns true if the result is Ok.
  • is_error(): Boolean - Returns true if the result is Error.
  • unwrap(): T - Returns the success value or panics if Error.

The ? Operator

The ? operator simplifies error propagation. If a Result is Error, it returns early.

function computation(): Result<Integer, String> {
    val: Integer = divide(10, 2)?; // Unwraps or returns Error
    val2: Integer = divide(val, 0)?; // Returns Error("Division by zero")
    return Result.Ok(val2);
}

arden check validates ? at the function boundary:

  • Option<T>? requires the enclosing function to return Option<...>
  • Result<T, E>? requires the enclosing function to return Result<..., E-compatible>
  • nested lambda bodies are checked against their own lambda return context, not the outer function's Option/Result return type
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