├── .github ├── FUNDING.yml └── workflows │ └── ci.yml ├── .gitignore ├── Cargo.toml ├── LICENSE-APACHE ├── LICENSE-MIT ├── README.md ├── src └── lib.rs └── tests └── test.rs /.github/FUNDING.yml: -------------------------------------------------------------------------------- 1 | github: dtolnay 2 | -------------------------------------------------------------------------------- /.github/workflows/ci.yml: -------------------------------------------------------------------------------- 1 | name: CI 2 | 3 | on: 4 | push: 5 | pull_request: 6 | workflow_dispatch: 7 | schedule: [cron: "40 1 * * *"] 8 | 9 | permissions: 10 | contents: read 11 | 12 | env: 13 | RUSTFLAGS: -Dwarnings 14 | 15 | jobs: 16 | pre_ci: 17 | uses: dtolnay/.github/.github/workflows/pre_ci.yml@master 18 | 19 | test: 20 | name: Rust ${{matrix.rust}} 21 | needs: pre_ci 22 | if: needs.pre_ci.outputs.continue 23 | runs-on: ubuntu-latest 24 | strategy: 25 | fail-fast: false 26 | matrix: 27 | rust: [nightly, beta, stable, 1.56.0] 28 | timeout-minutes: 45 29 | steps: 30 | - uses: actions/checkout@v4 31 | - uses: dtolnay/rust-toolchain@master 32 | with: 33 | toolchain: ${{matrix.rust}} 34 | - name: Enable type layout randomization 35 | run: echo RUSTFLAGS=${RUSTFLAGS}\ -Zrandomize-layout >> $GITHUB_ENV 36 | if: matrix.rust == 'nightly' 37 | - run: cargo test 38 | 39 | minimal: 40 | name: Minimal versions 41 | needs: pre_ci 42 | if: needs.pre_ci.outputs.continue 43 | runs-on: ubuntu-latest 44 | timeout-minutes: 45 45 | steps: 46 | - uses: actions/checkout@v4 47 | - uses: dtolnay/rust-toolchain@nightly 48 | - run: cargo generate-lockfile -Z minimal-versions 49 | - run: cargo check --locked 50 | 51 | doc: 52 | name: Documentation 53 | needs: pre_ci 54 | if: needs.pre_ci.outputs.continue 55 | runs-on: ubuntu-latest 56 | timeout-minutes: 45 57 | env: 58 | RUSTDOCFLAGS: -Dwarnings 59 | steps: 60 | - uses: actions/checkout@v4 61 | - uses: dtolnay/rust-toolchain@nightly 62 | - uses: dtolnay/install@cargo-docs-rs 63 | - run: cargo docs-rs 64 | 65 | clippy: 66 | name: Clippy 67 | runs-on: ubuntu-latest 68 | if: github.event_name != 'pull_request' 69 | timeout-minutes: 45 70 | steps: 71 | - uses: actions/checkout@v4 72 | - uses: dtolnay/rust-toolchain@clippy 73 | - run: cargo clippy -- -Dclippy::all -Dclippy::pedantic 74 | 75 | outdated: 76 | name: Outdated 77 | runs-on: ubuntu-latest 78 | if: github.event_name != 'pull_request' 79 | timeout-minutes: 45 80 | steps: 81 | - uses: actions/checkout@v4 82 | - uses: dtolnay/rust-toolchain@stable 83 | - uses: dtolnay/install@cargo-outdated 84 | - run: cargo outdated --workspace --exit-code 1 85 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | /target 2 | **/*.rs.bk 3 | Cargo.lock 4 | -------------------------------------------------------------------------------- /Cargo.toml: -------------------------------------------------------------------------------- 1 | [package] 2 | name = "enumn" 3 | version = "0.1.14" 4 | authors = ["David Tolnay "] 5 | categories = ["rust-patterns", "no-std", "no-std::no-alloc"] 6 | description = "Convert number to enum" 7 | documentation = "https://docs.rs/enumn" 8 | edition = "2021" 9 | keywords = ["enum", "integer"] 10 | license = "MIT OR Apache-2.0" 11 | repository = "https://github.com/dtolnay/enumn" 12 | rust-version = "1.56" 13 | 14 | [lib] 15 | proc-macro = true 16 | 17 | [dependencies] 18 | proc-macro2 = "1.0.74" 19 | quote = "1.0.35" 20 | syn = "2.0.46" 21 | 22 | [package.metadata.docs.rs] 23 | targets = ["x86_64-unknown-linux-gnu"] 24 | rustdoc-args = ["--generate-link-to-definition"] 25 | -------------------------------------------------------------------------------- /LICENSE-APACHE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. Definitions. 8 | 9 | "License" shall mean the terms and conditions for use, reproduction, 10 | and distribution as defined by Sections 1 through 9 of this document. 11 | 12 | "Licensor" shall mean the copyright owner or entity authorized by 13 | the copyright owner that is granting the License. 14 | 15 | "Legal Entity" shall mean the union of the acting entity and all 16 | other entities that control, are controlled by, or are under common 17 | control with that entity. For the purposes of this definition, 18 | "control" means (i) the power, direct or indirect, to cause the 19 | direction or management of such entity, whether by contract or 20 | otherwise, or (ii) ownership of fifty percent (50%) or more of the 21 | outstanding shares, or (iii) beneficial ownership of such entity. 22 | 23 | "You" (or "Your") shall mean an individual or Legal Entity 24 | exercising permissions granted by this License. 25 | 26 | "Source" form shall mean the preferred form for making modifications, 27 | including but not limited to software source code, documentation 28 | source, and configuration files. 29 | 30 | "Object" form shall mean any form resulting from mechanical 31 | transformation or translation of a Source form, including but 32 | not limited to compiled object code, generated documentation, 33 | and conversions to other media types. 34 | 35 | "Work" shall mean the work of authorship, whether in Source or 36 | Object form, made available under the License, as indicated by a 37 | copyright notice that is included in or attached to the work 38 | (an example is provided in the Appendix below). 39 | 40 | "Derivative Works" shall mean any work, whether in Source or Object 41 | form, that is based on (or derived from) the Work and for which the 42 | editorial revisions, annotations, elaborations, or other modifications 43 | represent, as a whole, an original work of authorship. For the purposes 44 | of this License, Derivative Works shall not include works that remain 45 | separable from, or merely link (or bind by name) to the interfaces of, 46 | the Work and Derivative Works thereof. 47 | 48 | "Contribution" shall mean any work of authorship, including 49 | the original version of the Work and any modifications or additions 50 | to that Work or Derivative Works thereof, that is intentionally 51 | submitted to Licensor for inclusion in the Work by the copyright owner 52 | or by an individual or Legal Entity authorized to submit on behalf of 53 | the copyright owner. For the purposes of this definition, "submitted" 54 | means any form of electronic, verbal, or written communication sent 55 | to the Licensor or its representatives, including but not limited to 56 | communication on electronic mailing lists, source code control systems, 57 | and issue tracking systems that are managed by, or on behalf of, the 58 | Licensor for the purpose of discussing and improving the Work, but 59 | excluding communication that is conspicuously marked or otherwise 60 | designated in writing by the copyright owner as "Not a Contribution." 61 | 62 | "Contributor" shall mean Licensor and any individual or Legal Entity 63 | on behalf of whom a Contribution has been received by Licensor and 64 | subsequently incorporated within the Work. 65 | 66 | 2. Grant of Copyright License. Subject to the terms and conditions of 67 | this License, each Contributor hereby grants to You a perpetual, 68 | worldwide, non-exclusive, no-charge, royalty-free, irrevocable 69 | copyright license to reproduce, prepare Derivative Works of, 70 | publicly display, publicly perform, sublicense, and distribute the 71 | Work and such Derivative Works in Source or Object form. 72 | 73 | 3. Grant of Patent License. Subject to the terms and conditions of 74 | this License, each Contributor hereby grants to You a perpetual, 75 | worldwide, non-exclusive, no-charge, royalty-free, irrevocable 76 | (except as stated in this section) patent license to make, have made, 77 | use, offer to sell, sell, import, and otherwise transfer the Work, 78 | where such license applies only to those patent claims licensable 79 | by such Contributor that are necessarily infringed by their 80 | Contribution(s) alone or by combination of their Contribution(s) 81 | with the Work to which such Contribution(s) was submitted. If You 82 | institute patent litigation against any entity (including a 83 | cross-claim or counterclaim in a lawsuit) alleging that the Work 84 | or a Contribution incorporated within the Work constitutes direct 85 | or contributory patent infringement, then any patent licenses 86 | granted to You under this License for that Work shall terminate 87 | as of the date such litigation is filed. 88 | 89 | 4. Redistribution. You may reproduce and distribute copies of the 90 | Work or Derivative Works thereof in any medium, with or without 91 | modifications, and in Source or Object form, provided that You 92 | meet the following conditions: 93 | 94 | (a) You must give any other recipients of the Work or 95 | Derivative Works a copy of this License; and 96 | 97 | (b) You must cause any modified files to carry prominent notices 98 | stating that You changed the files; and 99 | 100 | (c) You must retain, in the Source form of any Derivative Works 101 | that You distribute, all copyright, patent, trademark, and 102 | attribution notices from the Source form of the Work, 103 | excluding those notices that do not pertain to any part of 104 | the Derivative Works; and 105 | 106 | (d) If the Work includes a "NOTICE" text file as part of its 107 | distribution, then any Derivative Works that You distribute must 108 | include a readable copy of the attribution notices contained 109 | within such NOTICE file, excluding those notices that do not 110 | pertain to any part of the Derivative Works, in at least one 111 | of the following places: within a NOTICE text file distributed 112 | as part of the Derivative Works; within the Source form or 113 | documentation, if provided along with the Derivative Works; or, 114 | within a display generated by the Derivative Works, if and 115 | wherever such third-party notices normally appear. The contents 116 | of the NOTICE file are for informational purposes only and 117 | do not modify the License. You may add Your own attribution 118 | notices within Derivative Works that You distribute, alongside 119 | or as an addendum to the NOTICE text from the Work, provided 120 | that such additional attribution notices cannot be construed 121 | as modifying the License. 122 | 123 | You may add Your own copyright statement to Your modifications and 124 | may provide additional or different license terms and conditions 125 | for use, reproduction, or distribution of Your modifications, or 126 | for any such Derivative Works as a whole, provided Your use, 127 | reproduction, and distribution of the Work otherwise complies with 128 | the conditions stated in this License. 129 | 130 | 5. Submission of Contributions. Unless You explicitly state otherwise, 131 | any Contribution intentionally submitted for inclusion in the Work 132 | by You to the Licensor shall be under the terms and conditions of 133 | this License, without any additional terms or conditions. 134 | Notwithstanding the above, nothing herein shall supersede or modify 135 | the terms of any separate license agreement you may have executed 136 | with Licensor regarding such Contributions. 137 | 138 | 6. Trademarks. This License does not grant permission to use the trade 139 | names, trademarks, service marks, or product names of the Licensor, 140 | except as required for reasonable and customary use in describing the 141 | origin of the Work and reproducing the content of the NOTICE file. 142 | 143 | 7. Disclaimer of Warranty. Unless required by applicable law or 144 | agreed to in writing, Licensor provides the Work (and each 145 | Contributor provides its Contributions) on an "AS IS" BASIS, 146 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or 147 | implied, including, without limitation, any warranties or conditions 148 | of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A 149 | PARTICULAR PURPOSE. You are solely responsible for determining the 150 | appropriateness of using or redistributing the Work and assume any 151 | risks associated with Your exercise of permissions under this License. 152 | 153 | 8. Limitation of Liability. In no event and under no legal theory, 154 | whether in tort (including negligence), contract, or otherwise, 155 | unless required by applicable law (such as deliberate and grossly 156 | negligent acts) or agreed to in writing, shall any Contributor be 157 | liable to You for damages, including any direct, indirect, special, 158 | incidental, or consequential damages of any character arising as a 159 | result of this License or out of the use or inability to use the 160 | Work (including but not limited to damages for loss of goodwill, 161 | work stoppage, computer failure or malfunction, or any and all 162 | other commercial damages or losses), even if such Contributor 163 | has been advised of the possibility of such damages. 164 | 165 | 9. Accepting Warranty or Additional Liability. While redistributing 166 | the Work or Derivative Works thereof, You may choose to offer, 167 | and charge a fee for, acceptance of support, warranty, indemnity, 168 | or other liability obligations and/or rights consistent with this 169 | License. However, in accepting such obligations, You may act only 170 | on Your own behalf and on Your sole responsibility, not on behalf 171 | of any other Contributor, and only if You agree to indemnify, 172 | defend, and hold each Contributor harmless for any liability 173 | incurred by, or claims asserted against, such Contributor by reason 174 | of your accepting any such warranty or additional liability. 175 | 176 | END OF TERMS AND CONDITIONS 177 | -------------------------------------------------------------------------------- /LICENSE-MIT: -------------------------------------------------------------------------------- 1 | Permission is hereby granted, free of charge, to any 2 | person obtaining a copy of this software and associated 3 | documentation files (the "Software"), to deal in the 4 | Software without restriction, including without 5 | limitation the rights to use, copy, modify, merge, 6 | publish, distribute, sublicense, and/or sell copies of 7 | the Software, and to permit persons to whom the Software 8 | is furnished to do so, subject to the following 9 | conditions: 10 | 11 | The above copyright notice and this permission notice 12 | shall be included in all copies or substantial portions 13 | of the Software. 14 | 15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF 16 | ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED 17 | TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 18 | PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT 19 | SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 20 | CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 21 | OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR 22 | IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 23 | DEALINGS IN THE SOFTWARE. 24 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | Convert number to enum 2 | ====================== 3 | 4 | [github](https://github.com/dtolnay/enumn) 5 | [crates.io](https://crates.io/crates/enumn) 6 | [docs.rs](https://docs.rs/enumn) 7 | [build status](https://github.com/dtolnay/enumn/actions?query=branch%3Amaster) 8 | 9 | This crate provides a derive macro to generate a function for converting a 10 | primitive integer into the corresponding variant of an enum. _(This project is 11 | no longer maintained.)_ 12 | 13 | The generated function is named `n` and has the following signature: 14 | 15 | ```rust 16 | impl YourEnum { 17 | pub fn n(value: Repr) -> Option; 18 | } 19 | ``` 20 | 21 | where `Repr` is an integer type of the right size as described in more detail 22 | below. 23 | 24 | ## Example 25 | 26 | ```rust 27 | use enumn::N; 28 | 29 | #[derive(PartialEq, Debug, N)] 30 | enum Status { 31 | LegendaryTriumph, 32 | QualifiedSuccess, 33 | FortuitousRevival, 34 | IndeterminateStalemate, 35 | RecoverableSetback, 36 | DireMisadventure, 37 | AbjectFailure, 38 | } 39 | 40 | fn main() { 41 | let s = Status::n(1); 42 | assert_eq!(s, Some(Status::QualifiedSuccess)); 43 | 44 | let s = Status::n(9); 45 | assert_eq!(s, None); 46 | } 47 | ``` 48 | 49 | ## Signature 50 | 51 | The generated signature depends on whether the enum has a `#[repr(..)]` 52 | attribute. If a `repr` is specified, the input to `n` will be required to be of 53 | that type. 54 | 55 | ```rust 56 | #[derive(enumn::N)] 57 | #[repr(u8)] 58 | enum E { 59 | /* ... */ 60 | } 61 | 62 | // expands to: 63 | impl E { 64 | pub fn n(value: u8) -> Option { 65 | /* ... */ 66 | } 67 | } 68 | ``` 69 | 70 | On the other hand if no `repr` is specified then we get a signature that is 71 | generic over a variety of possible types. 72 | 73 | ```rust 74 | impl E { 75 | pub fn n>(value: REPR) -> Option { 76 | /* ... */ 77 | } 78 | } 79 | ``` 80 | 81 | ## Discriminants 82 | 83 | The conversion respects explicitly specified enum discriminants. Consider this 84 | enum: 85 | 86 | ```rust 87 | #[derive(enumn::N)] 88 | enum Letter { 89 | A = 65, 90 | B = 66, 91 | } 92 | ``` 93 | 94 | Here `Letter::n(65)` would return `Some(Letter::A)`. 95 | 96 |
97 | 98 | #### License 99 | 100 | 101 | Licensed under either of Apache License, Version 102 | 2.0 or MIT license at your option. 103 | 104 | 105 |
106 | 107 | 108 | Unless you explicitly state otherwise, any contribution intentionally submitted 109 | for inclusion in this crate by you, as defined in the Apache-2.0 license, shall 110 | be dual licensed as above, without any additional terms or conditions. 111 | 112 | -------------------------------------------------------------------------------- /src/lib.rs: -------------------------------------------------------------------------------- 1 | //! [![github]](https://github.com/dtolnay/enumn) [![crates-io]](https://crates.io/crates/enumn) [![docs-rs]](https://docs.rs/enumn) 2 | //! 3 | //! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github 4 | //! [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust 5 | //! [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs 6 | //! 7 | //!
8 | //! 9 | //! Convert number to enum. 10 | //! 11 | //! This crate provides a derive macro to generate a function for converting a 12 | //! primitive integer into the corresponding variant of an enum. 13 | //! 14 | //! The generated function is named `n` and has the following signature: 15 | //! 16 | //! ``` 17 | //! # const IGNORE: &str = stringify! { 18 | //! impl YourEnum { 19 | //! pub fn n(value: Repr) -> Option; 20 | //! } 21 | //! # }; 22 | //! ``` 23 | //! 24 | //! where `Repr` is an integer type of the right size as described in more 25 | //! detail below. 26 | //! 27 | //! # Example 28 | //! 29 | //! ``` 30 | //! use enumn::N; 31 | //! 32 | //! #[derive(PartialEq, Debug, N)] 33 | //! enum Status { 34 | //! LegendaryTriumph, 35 | //! QualifiedSuccess, 36 | //! FortuitousRevival, 37 | //! IndeterminateStalemate, 38 | //! RecoverableSetback, 39 | //! DireMisadventure, 40 | //! AbjectFailure, 41 | //! } 42 | //! 43 | //! fn main() { 44 | //! let s = Status::n(1); 45 | //! assert_eq!(s, Some(Status::QualifiedSuccess)); 46 | //! 47 | //! let s = Status::n(9); 48 | //! assert_eq!(s, None); 49 | //! } 50 | //! ``` 51 | //! 52 | //! # Signature 53 | //! 54 | //! The generated signature depends on whether the enum has a `#[repr(..)]` 55 | //! attribute. If a `repr` is specified, the input to `n` will be required to be 56 | //! of that type. 57 | //! 58 | //! ``` 59 | //! #[derive(enumn::N)] 60 | //! # enum E0 { 61 | //! # IGNORE 62 | //! # } 63 | //! # 64 | //! #[repr(u8)] 65 | //! enum E { 66 | //! /* ... */ 67 | //! # IGNORE 68 | //! } 69 | //! 70 | //! // expands to: 71 | //! impl E { 72 | //! pub fn n(value: u8) -> Option { 73 | //! /* ... */ 74 | //! # unimplemented!() 75 | //! } 76 | //! } 77 | //! ``` 78 | //! 79 | //! On the other hand if no `repr` is specified then we get a signature that is 80 | //! generic over a variety of possible types. 81 | //! 82 | //! ``` 83 | //! # enum E {} 84 | //! # 85 | //! impl E { 86 | //! pub fn n>(value: REPR) -> Option { 87 | //! /* ... */ 88 | //! # unimplemented!() 89 | //! } 90 | //! } 91 | //! ``` 92 | //! 93 | //! # Discriminants 94 | //! 95 | //! The conversion respects explicitly specified enum discriminants. Consider 96 | //! this enum: 97 | //! 98 | //! ``` 99 | //! #[derive(enumn::N)] 100 | //! enum Letter { 101 | //! A = 65, 102 | //! B = 66, 103 | //! } 104 | //! ``` 105 | //! 106 | //! Here `Letter::n(65)` would return `Some(Letter::A)`. 107 | 108 | #![doc(html_root_url = "https://docs.rs/enumn/0.1.14")] 109 | #![allow( 110 | clippy::missing_panics_doc, 111 | clippy::needless_doctest_main, 112 | clippy::single_match_else 113 | )] 114 | 115 | extern crate proc_macro; 116 | 117 | use proc_macro::TokenStream; 118 | use quote::quote; 119 | use syn::{parse_macro_input, Data, DeriveInput, Error, Fields, Ident}; 120 | 121 | #[proc_macro_derive(N)] 122 | pub fn derive(input: TokenStream) -> TokenStream { 123 | let input = parse_macro_input!(input as DeriveInput); 124 | 125 | let variants = match input.data { 126 | Data::Enum(data) => data.variants, 127 | Data::Struct(_) | Data::Union(_) => panic!("input must be an enum"), 128 | }; 129 | 130 | for variant in &variants { 131 | match variant.fields { 132 | Fields::Unit => {} 133 | Fields::Named(_) | Fields::Unnamed(_) => { 134 | let span = variant.ident.span(); 135 | let err = Error::new(span, "enumn: variant with data is not supported"); 136 | return err.to_compile_error().into(); 137 | } 138 | } 139 | } 140 | 141 | // Parse repr attribute like #[repr(u16)]. 142 | let mut repr = None; 143 | for attr in input.attrs { 144 | if attr.path().is_ident("repr") { 145 | if let Ok(name) = attr.parse_args::() { 146 | match name.to_string().as_str() { 147 | "u8" | "u16" | "u32" | "u64" | "u128" | "usize" | "i8" | "i16" | "i32" 148 | | "i64" | "i128" | "isize" => { 149 | repr = Some(quote!(#name)); 150 | } 151 | _ => {} 152 | } 153 | } 154 | } 155 | } 156 | 157 | let signature; 158 | let value; 159 | match repr { 160 | Some(ref repr) => { 161 | signature = quote! { 162 | fn n(value: #repr) 163 | }; 164 | value = quote!(value); 165 | } 166 | None => { 167 | repr = Some(quote!(i64)); 168 | signature = quote! { 169 | fn n>(value: REPR) 170 | }; 171 | value = quote! { 172 | >::into(value) 173 | }; 174 | } 175 | } 176 | 177 | let ident = input.ident; 178 | let declare_discriminants = variants.iter().map(|variant| { 179 | let variant = &variant.ident; 180 | quote! { 181 | const #variant: #repr = #ident::#variant as #repr; 182 | } 183 | }); 184 | let match_discriminants = variants.iter().map(|variant| { 185 | let variant = &variant.ident; 186 | quote! { 187 | discriminant::#variant => Some(#ident::#variant), 188 | } 189 | }); 190 | 191 | TokenStream::from(quote! { 192 | impl #ident { 193 | pub #signature -> Option { 194 | #[allow(non_camel_case_types)] 195 | struct discriminant; 196 | #[allow(non_upper_case_globals)] 197 | impl discriminant { 198 | #(#declare_discriminants)* 199 | } 200 | match #value { 201 | #(#match_discriminants)* 202 | _ => None, 203 | } 204 | } 205 | } 206 | }) 207 | } 208 | -------------------------------------------------------------------------------- /tests/test.rs: -------------------------------------------------------------------------------- 1 | use enumn::N; 2 | 3 | #[derive(Debug, N, PartialEq)] 4 | enum EmptyEnum {} 5 | 6 | #[test] 7 | fn test_empty() { 8 | assert_eq!(EmptyEnum::n(0), None); 9 | assert_eq!(EmptyEnum::n(1), None); 10 | assert_eq!(EmptyEnum::n(-1), None); 11 | } 12 | 13 | #[derive(Debug, N, PartialEq)] 14 | enum SimpleEnum { 15 | Case0, 16 | Case1, 17 | } 18 | 19 | #[test] 20 | fn test_simple() { 21 | assert_eq!(SimpleEnum::n(0), Some(SimpleEnum::Case0)); 22 | assert_eq!(SimpleEnum::n(1), Some(SimpleEnum::Case1)); 23 | assert_eq!(SimpleEnum::n(4), None); 24 | assert_eq!(SimpleEnum::n(-1), None); 25 | } 26 | 27 | #[derive(Debug, N, PartialEq)] 28 | #[repr(u8)] 29 | enum EnumWithRepr { 30 | Case0, 31 | } 32 | 33 | #[test] 34 | fn test_repr() { 35 | assert_eq!(EnumWithRepr::n(0), Some(EnumWithRepr::Case0)); 36 | assert_eq!(EnumWithRepr::n(255), None); 37 | } 38 | 39 | #[derive(Debug, N, PartialEq)] 40 | enum EnumWithDiscriminant { 41 | A = 10, 42 | B, // implicitly 11 43 | C = -80, 44 | } 45 | 46 | #[test] 47 | fn test_discriminant() { 48 | assert_eq!(EnumWithDiscriminant::n(10), Some(EnumWithDiscriminant::A)); 49 | assert_eq!(EnumWithDiscriminant::n(11), Some(EnumWithDiscriminant::B)); 50 | assert_eq!(EnumWithDiscriminant::n(-80), Some(EnumWithDiscriminant::C)); 51 | assert_eq!(EnumWithDiscriminant::n(12), None); 52 | } 53 | --------------------------------------------------------------------------------