std/expected

Result type for operations that can fail with error information.

Struct: expected<T, E>

Represents either a success value or an error.

union expected_storage<T, E> { 
    expected_value: T;
    unexpected_value: E;
}

struct expected<T, E> {
private:
    data: expected_storage<T, E>;
    has_expected_value: bool;
}

Static Methods

expected<T, E>::expect(data: T) -> expected<T, E>

Create a successful expected.

import "std/expected";

let result = expected<int64, string>::expect(42);

expected<T, E>::unexpected(error: E) -> expected<T, E>

Create a failed expected.

let result = expected<int64, string>::unexpected("Error occurred");

Instance Methods

is_expected(&this) -> bool

Check if this contains a value.

let result = expected<int64, string>::expect(42);
if result.is_expected() {
    println("Success");
}

is_unexpected(&this) -> bool

Check if this contains an error.

if result.is_unexpected() {
    println("Error occurred");
}

expected_value(this) -> T

Consume and return the value (panics if error).

let result = expected<int64, string>::expect(42);
let val = result.expected_value();  // 42

Warning: This method panics if the expected contains an error. Always check with is_expected() first or use expected_value_or().

unexpected_value(this) -> E

Consume and return the error (panics if value).

let result = expected<int64, string>::unexpected("Error");
let err = result.unexpected_value();  // "Error"

expected_value_or(this, default: T) -> T

Consume and return the value or a default.

let result = expected<int64, string>::unexpected("Error");
let val = result.expected_value_or(0);  // 0

unexpected_value_or(this, default: E) -> E

Consume and return the error or a default.

let result = expected<int64, string>::expect(42);
let err = result.unexpected_value_or("No error");  // "No error"