Cargo feature
A Cargo feature is a named compile-time configuration option that conditionally enables code, dependencies, or capabilities in a Rust package.
Write Powerful Rust Macros
A Cargo feature is a named compile-time configuration option that conditionally enables additive crate functionality or dependencies.
- How it is used
- Makes optional macro functionality selectable so consumers pull in only the library code they need.
- How deep it goes
- Demonstrates Cargo.toml declaration, cfg-gated imports and modules, consumer activation, failure testing, and default-feature trade-offs.
- Examples
- Uses an optional config_struct attribute macro, Serde derive macros, and Tokio’s macros feature and tokio-macros dependency.
- What you can do after
- Operate/configure optional macro APIs by declaring features, guarding code with cfg, and enabling requested features in dependencies.
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Refactoring to Rust
A Cargo feature is a named configuration option that conditionally enables code paths, dependencies, or capabilities in a Rust crate.
- How it is used
- Enables optional Rust capabilities such as Serde's generated parsing and deserialization support.
- How deep it goes
- Explains conditional compilation and demonstrates dependency configuration, but does not develop general feature design.
- Examples
- Uses Cargo.toml's serde derive feature and a Rust struct deriving Debug and Deserialize.
- What you can do after
- Apply it via Cargo to enable dependency capabilities and deserialize JSON into a typed Rust struct.
Related concepts
- additive featureincludes · An additive feature is a crate feature that only adds functionality and does not disable functionality already available.
- Cargopart of · Cargo is Rust’s package manager and build system for managing projects, dependencies, compilation, testing, and related workflows.
- conditional compilationconfigured by · Conditional compilation selects source-code regions for inclusion or exclusion based on conditions evaluated during compilation or preprocessing.
- cargo.tomlpart of · Cargo.toml is a TOML-formatted Rust package manifest declaring project metadata, dependencies, targets, and build configuration.
- dependencyconfigures · A software dependency is a component, resource, or prerequisite on which another software component or operation relies to function or proceed.
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