zc 0.4.0

Self-referential zero-copy structure
Documentation 
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/// Convenience macro for constructing a [`Zc`] type via a [`Dependant`]'s
/// [`From`].
///
/// See [`Zc::new()`] for an example.
///
/// This macro creates an intermediate function to annotate the lifetime
/// required for the `Construct` trait as the compiler is not smart enough yet
/// to infer it for us. See issues [22340] and [70263].
///
/// [22340]: https://github.com/rust-lang/rust/issues/22340
/// [70263]: https://github.com/rust-lang/rust/issues/70263
/// [`Zc`]: crate::Zc
/// [`Zc::new()`]: crate::Zc::new()
/// [`Dependant`]: crate::Dependant
#[macro_export]
macro_rules! from {
    ($owner:expr, $dependant:ident, $target:ty) => {{
        fn _new_fn(arg: &$target) -> $dependant<'_> {
            $dependant::from(arg)
        }
        zc::Zc::new($owner, _new_fn)
    }};
}

/// Convenience macro for constructing a [`Zc`] type via a [`Dependant`]'s
/// [`TryFrom`].
///
/// See [`Zc::try_new()`] for an example.
///
/// This macro creates an intermediate function to annotate the lifetime
/// required for the `TryConstruct` trait as the compiler is not smart enough
/// yet to infer it for us. See issues [22340] and [70263].
///
/// [22340]: https://github.com/rust-lang/rust/issues/22340
/// [70263]: https://github.com/rust-lang/rust/issues/70263
/// [`TryFrom`]: core::convert::TryFrom
/// [`Zc`]: crate::Zc
/// [`Zc::try_new()`]: crate::Zc::try_new()
/// [`Dependant`]: crate::Dependant
#[macro_export]
macro_rules! try_from {
    ($owner:expr, $dependant:ident, $target:ty) => {{
        fn _new_fn(
            arg: &$target,
        ) -> Result<$dependant<'_>, <$dependant as core::convert::TryFrom<&$target>>::Error>
        {
            <$dependant as core::convert::TryFrom<&$target>>::try_from(arg)
        }
        zc::Zc::try_new($owner, _new_fn)
    }};
}