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23 lines
567 B
23 lines
567 B
3 years ago
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# 条件编译、条件依赖
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3 years ago
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## 通过featre来实现不同的derive
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比如有一个类型，我们希望在不同包引用它的时候，派生引用不同的特征，可以这么做：
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在`Cargo.toml`中定义新的`feature`:
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```toml
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[features]
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sqlx = []
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```
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在类型定义处：
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```rust
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#[cfg_attr(feature = "sqlx", derive(sqlx::Type)]
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#[derive(Debug, PartialEq, Deserialize, Serialize, strum_macros::EnumString)]
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pub enum Role {Owner,Admin,User,}
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```
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在希望派生`sqlx`的包：
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```toml
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your_shared_crate = { version = "0.0.1", features = ["sqlx"] }
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```
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