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//! Applying wrapped by-ref functions within contexts with [`ref_apply`].
//!
//! Like [`Semiapplicative::apply`](crate::classes::Semiapplicative::apply), but the
//! wrapped functions receive `&A` instead of owned values. Uses
//! [`CloneFn<Ref>`](crate::classes::CloneFn) for the function wrappers.
//!
//! ### Examples
//!
//! ```
//! use fp_library::{
//! brands::*,
//! classes::*,
//! functions::*,
//! types::*,
//! };
//!
//! let f = RcLazy::pure(std::rc::Rc::new(|x: &i32| *x * 2) as std::rc::Rc<dyn Fn(&i32) -> i32>);
//! let x = RcLazy::pure(5);
//! let result = ref_apply::<RcFnBrand, LazyBrand<RcLazyConfig>, _, _>(&f, &x);
//! assert_eq!(*result.evaluate(), 10);
//! ```
#[fp_macros::document_module]
mod inner {
use {
crate::{
classes::*,
dispatch::Ref,
kinds::*,
},
fp_macros::*,
};
/// A type class for applying wrapped by-ref functions within contexts.
///
/// The wrapped functions have type `Fn(&A) -> B` (via [`CloneFn<Ref>`]),
/// so no `Clone` bound on `A` is needed. The function receives a reference
/// and produces an owned result.
#[kind(type Of<'a, A: 'a>: 'a;)]
pub trait RefSemiapplicative: RefLift + RefFunctor {
/// Applies a wrapped by-ref function within a context to a value within a context.
#[document_signature]
///
#[document_type_parameters(
"The lifetime of the values.",
"The brand of the cloneable function wrapper.",
"The type of the input value.",
"The type of the output value."
)]
///
#[document_parameters(
"The context containing the wrapped by-ref function(s).",
"The context containing the value(s)."
)]
///
#[document_returns(
"A new context containing the result(s) of applying the function(s) to the value(s)."
)]
#[document_examples]
///
/// ```
/// use fp_library::{
/// brands::*,
/// classes::*,
/// functions::*,
/// types::*,
/// };
///
/// let f = RcLazy::pure(std::rc::Rc::new(|x: &i32| *x * 2) as std::rc::Rc<dyn Fn(&i32) -> i32>);
/// let x = RcLazy::pure(5);
/// let result = LazyBrand::<RcLazyConfig>::ref_apply::<RcFnBrand, _, _>(&f, &x);
/// assert_eq!(*result.evaluate(), 10);
/// ```
fn ref_apply<'a, FnBrand: 'a + CloneFn<Ref>, A: 'a, B: 'a>(
ff: &Apply!(<Self as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, <FnBrand as CloneFn<Ref>>::Of<'a, A, B>>),
fa: &Apply!(<Self as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, A>),
) -> Apply!(<Self as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, B>);
}
/// Applies a wrapped by-ref function within a context to a value within a context.
///
/// Free function version that dispatches to [the type class' associated function][`RefSemiapplicative::ref_apply`].
#[document_signature]
///
#[document_type_parameters(
"The lifetime of the values.",
"The brand of the cloneable function wrapper.",
"The brand of the context.",
"The type of the input value.",
"The type of the output value."
)]
///
#[document_parameters(
"The context containing the wrapped by-ref function(s).",
"The context containing the value(s)."
)]
///
#[document_returns(
"A new context containing the result(s) of applying the function(s) to the value(s)."
)]
#[document_examples]
///
/// ```
/// use fp_library::{
/// brands::*,
/// classes::*,
/// functions::*,
/// types::*,
/// };
///
/// let f = RcLazy::pure(std::rc::Rc::new(|x: &i32| *x * 2) as std::rc::Rc<dyn Fn(&i32) -> i32>);
/// let x = RcLazy::pure(5);
/// let result = ref_apply::<RcFnBrand, LazyBrand<RcLazyConfig>, _, _>(&f, &x);
/// assert_eq!(*result.evaluate(), 10);
/// ```
pub fn ref_apply<'a, FnBrand: 'a + CloneFn<Ref>, Brand: RefSemiapplicative, A: 'a, B: 'a>(
ff: &Apply!(<Brand as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, <FnBrand as CloneFn<Ref>>::Of<'a, A, B>>),
fa: &Apply!(<Brand as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, A>),
) -> Apply!(<Brand as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, B>) {
Brand::ref_apply::<FnBrand, A, B>(ff, fa)
}
}
pub use inner::*;