126 lines
2.0 KiB
Markdown
126 lines
2.0 KiB
Markdown
# Derivative
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This crate provides a set of alternative `#[derive]` attributes for Rust.
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## Examples
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*derivative* uses attributes to make it possible to derive more implementations
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than the built-in `derive(Trait)`. Here are a few examples of stuffs you cannot
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just `derive`.
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You can derive `Default` on enumerations:
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<table>
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<tr>
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<th>
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With *derivative*
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</th>
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<th>
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[Original][default-value-source]
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</th>
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</tr>
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<tr>
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</tr>
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<tr class="readme-example">
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<td>
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{{#playground default-enum.rs}}
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</td>
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<td>
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{{#playground default-enum-orig.rs}}
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</td>
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</tr>
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</table>
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You can use different default values for some fields:
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<table>
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<tr>
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<th>
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With *derivative*
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</th>
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<th>
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[Original][default-value-source]
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</th>
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</tr>
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<tr>
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</tr>
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<tr class="readme-example">
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<td>
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{{#playground default-value.rs}}
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</td>
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<td>
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{{#playground default-value-orig.rs}}
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</td>
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</tr>
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</table>
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Want a transparent `Debug` implementation for your wrapper? We got that:
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<table>
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<tr>
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<th>
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With *derivative*
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</th>
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<th>
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[Original][transparent-source]
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</th>
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</tr>
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<tr>
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</tr>
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<tr class="readme-example">
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<td>
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{{#playground debug-transparent.rs}}
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</td>
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<td>
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{{#playground debug-transparent-orig.rs}}
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</td>
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</tr>
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</table>
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Need to ignore a field? We got that too:
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<table>
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<tr>
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<th>
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With *derivative*
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</th>
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<th>
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[Original][eq-ignore-source]
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</th>
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</tr>
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<tr>
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</tr>
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<tr class="readme-example">
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<td>
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{{#playground eq-ignore.rs}}
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</td>
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<td>
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{{#playground eq-ignore-orig.rs}}
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</td>
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</tr>
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</table>
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[default-value-source]: https://github.com/rust-lang-nursery/regex/blob/3cfef1e79d135a3e8a670aff53e7fabef453a3e1/src/re_builder.rs#L12-L39
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[default-enum-source]: https://github.com/rust-lang/rust/blob/16eeeac783d2ede28e09f2a433c612dea309fe33/src/libcore/option.rs#L714-L718
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[transparent-source]: https://github.com/rust-lang/rust/blob/5457c35ece57bbc4a65baff239a02d6abb81c8a2/src/libcore/num/mod.rs#L46-L54
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[eq-ignore-source]: https://github.com/steveklabnik/semver/blob/baa0fbb57c80a7fb344fbeedac24a28439ddf5b5/src/version.rs#L196-L205
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