define_into_enum/
lib.rs

1#![doc = include_str!("../README.md")]
2#![no_std]
3
4#[macro_export]
5macro_rules! define_into_enum {
6  {
7    $(#[$attr:meta])*
8    $vis:vis enum $name:ident $(< $generic:lifetime >)* {
9      $(#[$variant_attr1:meta])*
10      $variant1:ident ($type1:ty),
11      $(
12        $(#[$variant_attr:meta])*
13        $variant:ident ($type:ty),
14      )*
15    }
16    $into:pat,
17    $output:expr
18  } => {
19    $(#[$attr])*
20    $vis enum $name $(<$generic>)* {
21      $(#[$variant_attr1])*
22      $variant1($type1),
23      $(
24        $(#[$variant_attr])*
25        $variant($type),
26      )*
27    }
28
29    impl$(<$generic>)* Into <$type1> for $name $(<$generic>)* {
30      fn into(self) -> $type1 {
31        match self {
32          $(
33            Self::$variant( $into ) => ( $output ),
34          )+
35          Self::$variant1( $into ) => ( $output ),
36        }
37      }
38    }
39  }
40}
41
42
43#[cfg(test)]
44mod tests {
45  use super::*;
46
47  #[test]
48  fn test_into_impl() {
49    define_into_enum! {
50      #[derive(Debug, PartialEq)]
51      pub enum TestEnum<'a> {
52        #[allow(dead_code)]
53        Variant1(&'a str),
54        #[allow(dead_code)]
55        Variant2(&'a str),
56        #[allow(dead_code)]
57        Variant3(&'a str),
58      }
59      v, v
60    }
61
62  }
63
64  #[test]
65  fn test_enum_variants() {
66    define_into_enum! {
67      #[derive(Debug, PartialEq)]
68      pub enum TestEnum {
69        #[allow(dead_code)]
70        Variant1(i32),
71        #[allow(dead_code)]
72        Variant2(i32),
73        #[allow(dead_code)]
74        Variant3(i32),
75      }
76      v, v
77    }
78
79    assert_eq!(
80      Into::<i32>::into(TestEnum::Variant3(0)),
81      0,
82      "Incorrect conversion for Variant1"
83    );
84    assert_eq!(
85      Into::<i32>::into(TestEnum::Variant3(8i32)),
86      8,
87      "Incorrect conversion for Variant2"
88    );
89    assert_eq!(
90      Into::<i32>::into(TestEnum::Variant3(-9i32)),
91      -9,
92      "Incorrect conversion for Variant3"
93    );
94  }
95}
define_into_enum/lib.rs

define_into_enum/
lib.rs
