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/// A trait for creating a default instance of a type, which is not **necessarily useful**.
///
/// The difference of `PseudoDefault` from `Default` is the relaxed expectation of the created instance to be useful.
///
/// The main use case of the trait is when we need to create a cheap instance of a type without any arguments to throw away.
/// This sounds exactly the same as the `Default`s definition.
/// However, the instance created by `pseudo_default` does not need to be a decent one, it is totally fine if it is useless.
///
/// We would most possibly need such an instance when we need to swap it with another instance or fill a gap in a collection.
/// `PseudoDefault` allows us to achieve this without requiring to use unsafe code and leaving the memory location uninitialized.
///
/// # Example
///
/// Consider the following fictional type `Share` which divides a whole into pieces.
/// Without providing the `number_of_shares`, this type is meaningless; i.e., we cannot justify implementing `Default`.
/// However, if we need to be able to create dummy Share's, we can simply use `pseudo_default`.
/// The created share will be useless; however, a valid and safe `Share` instance.
///
/// ```rust
/// use orx_pseudo_default::PseudoDefault;
///
/// struct Share {
///     number_of_shares: std::num::NonZeroUsize,
/// }
///
/// impl Share {
///     fn share_size(&self, whole_amount: usize) -> usize {
///         whole_amount / self.number_of_shares
///     }
/// }
///
/// impl PseudoDefault for Share {
///     fn pseudo_default() -> Self {
///         Self {
///             number_of_shares: std::num::NonZeroUsize::new(1).unwrap(),
///         }
///     }
/// }
/// ```
pub trait PseudoDefault {
    /// A trait for creating a default instance of a type, which is not **necessarily useful**.
    ///
    /// The difference of `PseudoDefault` from `Default` is the relaxed expectation of the created instance to be useful.
    ///
    /// The main use case of the trait is when we need to create a cheap instance of a type without any arguments to throw away.
    /// This sounds exactly the same as the `Default`s definition.
    /// However, the instance created by `pseudo_default` does not need to be a decent one, it is totally fine if it is useless.
    ///
    /// We would most possibly need such an instance when we need to swap it with another instance or fill a gap in a collection.
    /// `PseudoDefault` allows us to achieve this without requiring to use unsafe code and leaving the memory location uninitialized.
    ///
    /// # Example
    ///
    /// Consider the following fictional type `Share` which divides a whole into pieces.
    /// Without providing the `number_of_shares`, this type is meaningless; i.e., we cannot justify implementing `Default`.
    /// However, if we need to be able to create dummy Share's, we can simply use `pseudo_default`.
    /// The created share will be useless; however, a valid and safe `Share` instance.
    ///
    /// ```rust
    /// use orx_pseudo_default::PseudoDefault;
    ///
    /// struct Share {
    ///     number_of_shares: std::num::NonZeroUsize,
    /// }
    ///
    /// impl Share {
    ///     fn share_size(&self, whole_amount: usize) -> usize {
    ///         whole_amount / self.number_of_shares
    ///     }
    /// }
    ///
    /// impl PseudoDefault for Share {
    ///     fn pseudo_default() -> Self {
    ///         Self {
    ///             number_of_shares: std::num::NonZeroUsize::new(1).unwrap(),
    ///         }
    ///     }
    /// }
    /// ```
    fn pseudo_default() -> Self;
}