fp_library/classes/
pointed.rs

1//! Contexts that can be initialized with a value via the [`pure`] operation.
2//!
3//! ### Examples
4//!
5//! ```
6//! use fp_library::{
7//! 	brands::*,
8//! 	functions::*,
9//! };
10//!
11//! let x = pure::<OptionBrand, _>(5);
12//! assert_eq!(x, Some(5));
13//! ```
14
15#[fp_macros::document_module]
16mod inner {
17	use {
18		crate::kinds::*,
19		fp_macros::*,
20	};
21
22	/// A type class for contexts that can be initialized with a value.
23	#[kind(type Of<'a, A: 'a>: 'a;)]
24	pub trait Pointed {
25		/// The value wrapped in the context.
26		///
27		/// This method wraps a value in a context.
28		#[document_signature]
29		///
30		#[document_type_parameters("The lifetime of the value.", "The type of the value to wrap.")]
31		///
32		#[document_parameters("The value to wrap.")]
33		///
34		#[document_returns("A new context containing the value.")]
35		#[document_examples]
36		///
37		/// ```
38		/// use fp_library::{
39		/// 	brands::*,
40		/// 	functions::*,
41		/// };
42		///
43		/// let x = pure::<OptionBrand, _>(5);
44		/// assert_eq!(x, Some(5));
45		/// ```
46		fn pure<'a, A: 'a>(a: A) -> Apply!(<Self as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, A>);
47	}
48
49	/// The value wrapped in the context.
50	///
51	/// Free function version that dispatches to [the type class' associated function][`Pointed::pure`].
52	#[document_signature]
53	///
54	#[document_type_parameters(
55		"The lifetime of the value.",
56		"The brand of the context.",
57		"The type of the value to wrap."
58	)]
59	///
60	#[document_parameters("The value to wrap.")]
61	///
62	#[document_returns("A new context containing the value.")]
63	#[document_examples]
64	///
65	/// ```
66	/// use fp_library::{
67	/// 	brands::*,
68	/// 	functions::*,
69	/// };
70	///
71	/// let x = pure::<OptionBrand, _>(5);
72	/// assert_eq!(x, Some(5));
73	/// ```
74	pub fn pure<'a, Brand: Pointed, A: 'a>(
75		a: A
76	) -> Apply!(<Brand as Kind!( type Of<'a, T: 'a>: 'a; )>::Of<'a, A>) {
77		Brand::pure(a)
78	}
79}
80
81pub use inner::*;
fp_library/classes/pointed.rs

fp_library/classes/
pointed.rs
