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//! Coercion of sized closures into `dyn Fn` trait objects behind a
//! [`Pointer`](crate::classes::Pointer).
//!
//! ### Examples
//!
//! ```
//! use fp_library::{
//! brands::*,
//! classes::*,
//! };
//!
//! let f = <BoxBrand as ToDynFn>::new(|x: i32| x + 1);
//! assert_eq!(f(1), 2);
//! ```
#[fp_macros::document_module]
mod inner {
use {
crate::classes::Pointer,
fp_macros::*,
};
/// Coerces sized closures into `dyn Fn` trait objects behind a
/// [`Pointer`](crate::classes::Pointer).
///
/// This trait extends [`Pointer`](crate::classes::Pointer) to add the
/// ability to wrap concrete closure types into type-erased `dyn Fn` trait
/// objects stored in the pointer. For example, `BoxBrand` coerces
/// `impl Fn(A) -> B` into `Box<dyn Fn(A) -> B>`.
///
/// For clonable variants, see
/// [`ToDynCloneFn`](crate::classes::ToDynCloneFn) (which extends
/// [`RefCountedPointer`](crate::classes::RefCountedPointer)). For
/// thread-safe variants, see
/// [`ToDynSendFn`](crate::classes::ToDynSendFn)
/// (which extends
/// [`SendRefCountedPointer`](crate::classes::SendRefCountedPointer)).
pub trait ToDynFn: Pointer + 'static {
/// Coerces a sized closure to a `dyn Fn` wrapped in this pointer type.
#[document_signature]
///
#[document_type_parameters(
"The lifetime of the closure.",
"The input type of the function.",
"The output type of the function."
)]
///
#[document_parameters("The closure to coerce.")]
///
#[document_returns("The closure wrapped in the pointer type as a trait object.")]
#[document_examples]
///
/// ```
/// use fp_library::{
/// brands::*,
/// classes::*,
/// };
///
/// let f = <BoxBrand as ToDynFn>::new(|x: i32| x + 1);
/// assert_eq!(f(1), 2);
/// ```
fn new<'a, A: 'a, B: 'a>(
f: impl 'a + Fn(A) -> B
) -> <Self as Pointer>::Of<'a, dyn 'a + Fn(A) -> B>;
/// Coerces a sized by-reference closure to a `dyn Fn(&A) -> B` wrapped in this pointer type.
#[document_signature]
///
#[document_type_parameters(
"The lifetime of the closure.",
"The input type (the closure receives `&A`).",
"The output type of the function."
)]
///
#[document_parameters("The closure to coerce.")]
///
#[document_returns(
"The closure wrapped in the pointer type as a by-reference trait object."
)]
#[document_examples]
///
/// ```
/// use fp_library::{
/// brands::*,
/// classes::*,
/// };
///
/// let f = <BoxBrand as ToDynFn>::ref_new(|x: &i32| *x + 1);
/// assert_eq!(f(&1), 2);
/// ```
fn ref_new<'a, A: 'a, B: 'a>(
f: impl 'a + Fn(&A) -> B
) -> <Self as Pointer>::Of<'a, dyn 'a + Fn(&A) -> B>;
}
/// Coerces a sized closure to a `dyn Fn` wrapped in a pointer.
///
/// Free function version that dispatches to [`ToDynFn::new`].
#[document_signature]
///
#[document_type_parameters(
"The lifetime of the closure.",
"The pointer brand.",
"The input type of the function.",
"The output type of the function."
)]
///
#[document_parameters("The closure to coerce.")]
///
#[document_returns("The closure wrapped in the pointer type as a trait object.")]
#[document_examples]
///
/// ```
/// use fp_library::{
/// brands::*,
/// classes::to_dyn_fn::*,
/// };
///
/// let f = to_dyn_fn::<BoxBrand, _, _>(|x: i32| x + 1);
/// assert_eq!(f(1), 2);
/// ```
pub fn to_dyn_fn<'a, Brand: ToDynFn, A: 'a, B: 'a>(
f: impl 'a + Fn(A) -> B
) -> <Brand as Pointer>::Of<'a, dyn 'a + Fn(A) -> B> {
<Brand as ToDynFn>::new(f)
}
/// Coerces a sized by-reference closure to a `dyn Fn(&A) -> B` wrapped in a pointer.
///
/// Free function version that dispatches to [`ToDynFn::ref_new`].
#[document_signature]
///
#[document_type_parameters(
"The lifetime of the closure.",
"The pointer brand.",
"The input type (the closure receives `&A`).",
"The output type of the function."
)]
///
#[document_parameters("The closure to coerce.")]
///
#[document_returns("The closure wrapped in the pointer type as a by-reference trait object.")]
#[document_examples]
///
/// ```
/// use fp_library::{
/// brands::*,
/// classes::to_dyn_fn::*,
/// };
///
/// let f = to_ref_dyn_fn::<BoxBrand, _, _>(|x: &i32| *x + 1);
/// assert_eq!(f(&1), 2);
/// ```
pub fn to_ref_dyn_fn<'a, Brand: ToDynFn, A: 'a, B: 'a>(
f: impl 'a + Fn(&A) -> B
) -> <Brand as Pointer>::Of<'a, dyn 'a + Fn(&A) -> B> {
<Brand as ToDynFn>::ref_new(f)
}
}
pub use inner::*;