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/// Represents the result of parsing or looking up a value.
///
/// This enum is generic over the type being parsed. It models four possible outcomes:
/// - [`Unparsed`](PickerResult::Unparsed): The value has not yet been parsed (default).
/// - [`Parsed`](PickerResult::Parsed): The value was successfully parsed into `Type`.
/// - [`NotFound`](PickerResult::NotFound): The requested value could not be found.
/// - [`ParseError`](PickerResult::ParseError): The input could not be parsed due to a format error.
#[derive(Default)]
pub enum PickerResult<Type> {
/// The value has not yet been parsed (default).
#[default]
Unparsed,
/// The value was successfully parsed into `Type`.
Parsed(Type),
/// The requested value could not be found.
NotFound,
/// The input could not be parsed due to a format error.
ParseError,
}
impl<Type, E> From<Result<Type, E>> for PickerResult<Type> {
/// Converts a `Result<Type, E>` into a `PickerResult<Type>`.
///
/// - `Ok(value)` maps to [`Parsed(value)`](PickerResult::Parsed).
/// - `Err(_)` maps to [`ParseError`](PickerResult::ParseError).
fn from(result: Result<Type, E>) -> Self {
match result {
Ok(value) => PickerResult::Parsed(value),
Err(_) => PickerResult::ParseError,
}
}
}
impl<Type> From<Option<Type>> for PickerResult<Type> {
/// Converts an `Option<Type>` into a `PickerResult<Type>`.
///
/// - `Some(value)` maps to [`Parsed(value)`](PickerResult::Parsed).
/// - `None` maps to [`NotFound`](PickerResult::NotFound).
fn from(option: Option<Type>) -> Self {
match option {
Some(value) => PickerResult::Parsed(value),
None => PickerResult::NotFound,
}
}
}
impl<Type> PickerResult<Type> {
/// Returns `true` if the result is [`Parsed`](PickerResult::Parsed).
///
/// # Examples
///
/// ```
/// use mingling_picker::PickerResult;
///
/// let result: PickerResult<i32> = PickerResult::Parsed(42);
/// assert!(result.is_parsed());
///
/// let result: PickerResult<i32> = PickerResult::NotFound;
/// assert!(!result.is_parsed());
/// ```
pub fn is_parsed(&self) -> bool {
matches!(self, PickerResult::Parsed(_))
}
/// Returns `true` if the result is [`Parsed`](PickerResult::Parsed) or [`NotFound`](PickerResult::NotFound).
/// i.e., the value exists (was either found or not yet parsed, but not a parse error).
/// Typically indicates the value was "found" in some sense.
///
/// # Examples
///
/// ```
/// use mingling_picker::PickerResult;
///
/// let result: PickerResult<i32> = PickerResult::Parsed(42);
/// assert!(result.is_found());
///
/// let result: PickerResult<i32> = PickerResult::NotFound;
/// assert!(result.is_found());
///
/// let result: PickerResult<i32> = PickerResult::ParseError;
/// assert!(!result.is_found());
/// ```
pub fn is_found(&self) -> bool {
matches!(self, PickerResult::Parsed(_) | PickerResult::NotFound)
}
/// Returns `true` if the result is [`ParseError`](PickerResult::ParseError).
///
/// # Examples
///
/// ```
/// use mingling_picker::PickerResult;
///
/// let result: PickerResult<i32> = PickerResult::ParseError;
/// assert!(result.is_err());
///
/// let result: PickerResult<i32> = PickerResult::Parsed(10);
/// assert!(!result.is_err());
/// ```
pub fn is_err(&self) -> bool {
matches!(self, PickerResult::ParseError)
}
/// Returns `Some(&Type)` if [`Parsed`](PickerResult::Parsed), otherwise `None`.
///
/// # Examples
///
/// ```
/// use mingling_picker::PickerResult;
///
/// let result: PickerResult<i32> = PickerResult::Parsed(42);
/// assert_eq!(result.parsed(), Some(&42));
///
/// let result: PickerResult<i32> = PickerResult::NotFound;
/// assert_eq!(result.parsed(), None);
/// ```
pub fn parsed(&self) -> Option<&Type> {
if let PickerResult::Parsed(value) = self {
Some(value)
} else {
None
}
}
/// Returns the contained [`Parsed`](PickerResult::Parsed) value or panics with a given message.
///
/// # Panics
/// Panics if the value is not [`Parsed`](PickerResult::Parsed), with a message including the provided `msg`.
///
/// # Examples
///
/// ```should_panic
/// use mingling_picker::PickerResult;
///
/// let result: PickerResult<i32> = PickerResult::NotFound;
/// result.expect("expected a parsed value");
/// ```
pub fn expect(self, msg: &str) -> Type {
match self {
PickerResult::Parsed(value) => value,
_ => panic!("{}", msg),
}
}
/// Returns the contained [`Parsed`](PickerResult::Parsed) value or panics.
///
/// # Panics
/// Panics if the value is not [`Parsed`](PickerResult::Parsed).
///
/// # Examples
///
/// ```
/// use mingling_picker::PickerResult;
///
/// let result: PickerResult<i32> = PickerResult::Parsed(42);
/// assert_eq!(result.unwrap(), 42);
/// ```
///
/// ```should_panic
/// use mingling_picker::PickerResult;
///
/// let result: PickerResult<i32> = PickerResult::NotFound;
/// result.unwrap();
/// ```
pub fn unwrap(self) -> Type {
match self {
PickerResult::Parsed(value) => value,
PickerResult::Unparsed => {
panic!("called `PickerResult::unwrap()` on an `Unparsed` value")
}
PickerResult::NotFound => {
panic!("called `PickerResult::unwrap()` on a `NotFound` value")
}
PickerResult::ParseError => {
panic!("called `PickerResult::unwrap()` on a `ParseError` value")
}
}
}
/// Returns the contained [`Parsed`](PickerResult::Parsed) value or a provided `default`.
///
/// # Examples
///
/// ```
/// use mingling_picker::PickerResult;
///
/// let result: PickerResult<i32> = PickerResult::Parsed(42);
/// assert_eq!(result.unwrap_or(0), 42);
///
/// let result: PickerResult<i32> = PickerResult::NotFound;
/// assert_eq!(result.unwrap_or(0), 0);
/// ```
pub fn unwrap_or(self, default: Type) -> Type {
match self {
PickerResult::Parsed(value) => value,
_ => default,
}
}
/// Returns the contained [`Parsed`](PickerResult::Parsed) value or computes it from a closure.
///
/// # Examples
///
/// ```
/// use mingling_picker::PickerResult;
///
/// let result: PickerResult<i32> = PickerResult::Parsed(42);
/// assert_eq!(result.unwrap_or_else(|| 0), 42);
///
/// let result: PickerResult<i32> = PickerResult::NotFound;
/// assert_eq!(result.unwrap_or_else(|| 0), 0);
/// ```
pub fn unwrap_or_else<F: FnOnce() -> Type>(self, f: F) -> Type {
match self {
PickerResult::Parsed(value) => value,
_ => f(),
}
}
/// Returns the contained [`Parsed`](PickerResult::Parsed) value or the default value of `Type`.
///
/// # Examples
///
/// ```
/// use mingling_picker::PickerResult;
///
/// let result: PickerResult<i32> = PickerResult::Parsed(42);
/// assert_eq!(result.unwrap_or_default(), 42);
///
/// let result: PickerResult<i32> = PickerResult::NotFound;
/// assert_eq!(result.unwrap_or_default(), 0);
/// ```
pub fn unwrap_or_default(self) -> Type
where
Type: Default,
{
match self {
PickerResult::Parsed(value) => value,
_ => Type::default(),
}
}
}
|
