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//! Thread-safe combining of two by-ref contexts, keeping the second value, with [`send_ref_apply_second`].
//!
//! This is the thread-safe counterpart of [`RefApplySecond`](crate::classes::RefApplySecond).
//!
//! ### Examples
//!
//! ```
//! use fp_library::{
//! brands::*,
//! functions::*,
//! types::*,
//! };
//!
//! let x = ArcLazy::new(|| 3);
//! let y = ArcLazy::new(|| 4);
//! let result = send_ref_apply_second::<LazyBrand<ArcLazyConfig>, _, _>(&x, &y);
//! assert_eq!(*result.evaluate(), 4);
//! ```
#[fp_macros::document_module]
mod inner {
use {
crate::kinds::*,
fp_macros::*,
};
/// A type class for combining two thread-safe by-ref contexts, keeping the second value.
///
/// Requires `B: Clone + Send + Sync` because the closure receives `&B` and must produce
/// an owned `B`. The default implementation uses [`SendRefLift::send_ref_lift2`](crate::classes::SendRefLift::send_ref_lift2).
#[kind(type Of<'a, A: 'a>: 'a;)]
pub trait SendRefApplySecond: crate::classes::SendRefLift {
/// Combines two contexts, keeping the value from the second.
#[document_signature]
///
#[document_type_parameters(
"The lifetime of the values.",
"The type of the value in the first context.",
"The type of the value in the second context. Must be `Clone + Send + Sync`."
)]
///
#[document_parameters("The first context.", "The second context.")]
///
#[document_returns("A new context containing the value from the second context.")]
#[document_examples]
///
/// ```
/// use fp_library::{
/// brands::*,
/// classes::*,
/// types::*,
/// };
///
/// let x = ArcLazy::new(|| 3);
/// let y = ArcLazy::new(|| 4);
/// let result = LazyBrand::<ArcLazyConfig>::send_ref_apply_second(&x, &y);
/// assert_eq!(*result.evaluate(), 4);
/// ```
fn send_ref_apply_second<'a, A: Send + Sync + 'a, B: Clone + Send + Sync + 'a>(
fa: &Apply!(<Self as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, A>),
fb: &Apply!(<Self as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, B>),
) -> Apply!(<Self as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, B>) {
Self::send_ref_lift2(|_: &A, b: &B| b.clone(), fa, fb)
}
}
/// Blanket implementation of [`SendRefApplySecond`].
#[document_type_parameters("The brand type.")]
impl<Brand: crate::classes::SendRefLift> SendRefApplySecond for Brand {}
/// Combines two thread-safe contexts, keeping the value from the second.
///
/// Free function version that dispatches to [the type class' associated function][`SendRefApplySecond::send_ref_apply_second`].
#[document_signature]
///
#[document_type_parameters(
"The lifetime of the values.",
"The brand of the context.",
"The type of the value in the first context.",
"The type of the value in the second context. Must be `Clone + Send + Sync`."
)]
///
#[document_parameters("The first context.", "The second context.")]
///
#[document_returns("A new context containing the value from the second context.")]
#[document_examples]
///
/// ```
/// use fp_library::{
/// brands::*,
/// functions::*,
/// types::*,
/// };
///
/// let x = ArcLazy::new(|| 3);
/// let y = ArcLazy::new(|| 4);
/// let result = send_ref_apply_second::<LazyBrand<ArcLazyConfig>, _, _>(&x, &y);
/// assert_eq!(*result.evaluate(), 4);
/// ```
pub fn send_ref_apply_second<
'a,
Brand: SendRefApplySecond,
A: Send + Sync + 'a,
B: Clone + Send + Sync + 'a,
>(
fa: &Apply!(<Brand as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, A>),
fb: &Apply!(<Brand as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, B>),
) -> Apply!(<Brand as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, B>) {
Brand::send_ref_apply_second(fa, fb)
}
}
pub use inner::*;