const_dispatch/
primitive.rs

1//! The "`impl`s" for primitive types such as `bool` and `u8`
2//!
3//! ```rust, ignore
4//! /// Pseudo-code
5//! mod ::const_dispatch::primitive {
6//!     impl ConstDispatch for bool { /* magic */ }
7//!     impl ConstDispatch for u8 { /* magic */ }
8//! }
9//! ```
10//!
11//! ## Example
12//!
13//! ```rust
14//! use ::const_dispatch::{const_dispatch, primitive::bool};
15//!
16//! fn inner<const VERBOSE: bool>() {
17//!     // ...
18//! }
19//!
20//! fn main() {
21//!     let verbose = ::std::env::var("VERBOSE").map_or(false, |s| s == "1");
22//!     const_dispatch!(verbose, |const VERBOSE: bool| {
23//!         inner::<VERBOSE>()
24//!     })
25//! }
26//! ```
27//!
28//! Make sure to import these (either individually, or as a blob import from the
29//! <code>[crate::prelude]::*</code>) in order for [`const_dispatch!`][crate::const_dispatch] to
30//! work with `u8` and `bool` properly.
31
32#[doc(hidden)]
33#[macro_export]
34macro_rules! bool {
35    (
36        $scrutinee:expr, |const $C:ident| $body:block
37    ) => (
38        match $scrutinee {
39            | true => {
40                const $C: ::core::primitive::bool = true;
41                {
42                    $crate::ඞ::try_hide!($scrutinee);
43                    $body
44                }
45            },
46            | false => {
47                const $C: ::core::primitive::bool = false;
48                {
49                    $crate::ඞ::try_hide!($scrutinee);
50                    $body
51                }
52            },
53        }
54    );
55
56    (
57        $scrutinee:expr,
58        $macro_input:tt => $macro_output:tt
59    ) => ({
60        macro_rules! __emit__ { $macro_input => $macro_output }
61        match $scrutinee {
62            | true => {
63                $crate::ඞ::try_hide!($scrutinee);
64                emit! {
65                    true
66                }
67            },
68            | false => {
69                $crate::ඞ::try_hide!($scrutinee);
70                emit! {
71                    false
72                }
73            },
74        }
75    });
76}
77
78#[doc(no_inline)]
79pub use bool;
80
81impl crate::ඞ::MacroDerived for bool {} /* as bool */
82
83::const_dispatch_proc_macros::ඞimpl_for_u8!();
84
85#[doc(no_inline)]
86pub use u8;
87
88impl crate::ඞ::MacroDerived for u8 {} /* as u8 */
const_dispatch/primitive.rs

const_dispatch/
primitive.rs
