inline-config

Effortlessly embed config modules and access with any compatible types.

A procedual macro config is provided to parse sources at compile time, generate corresponding data structures, from which we can access values via the Index trait and the Into trait.

Features

• JSON, YAML, TOML formats are supported.
• Both inline literal configs and file inclusions are supported; overwriting is supported.
• Compile-time source validation. Errors are clearly reported for easier debugging.
• Infallible data access. Path existence and type compatibility are both checked at compile time.
• Define custom data structures to access data.
• The feature flag indexmap enables preserving orders of tables. Check this example for details.

Usage

Add inline-config to your dependencies

cargo add inline-config

In your source file, declare a module using config holding the config data

use inline_config::config;

// Declare a config module containing literal sources.
// With `export(static = MY_CONFIG)`, a static variable `MY_CONFIG` will be brought into scope.
#[config(export(static = MY_CONFIG))]
mod my_config {
    // When there are multiple sources, latter ones overwrite former ones.
    // Including a file from disk is also possible, see `examples/include.rs`.
    toml!(
        r#"
        title = "TOML example"

        [server]
        owner = "Tom"
        timeout = 2000
        ports = [ 8000, 8001, 8002 ]
        "#
    );
    toml!(
        r#"
        [server]
        timeout = 5000
        "#
    );
}

Then, access the data inside using the path!() macro

use inline_config::path;

// Multiple types may implement `From` trait, so type annotations are required.
let title: &str = MY_CONFIG[path!(title)].into();
assert_eq!("TOML example", title);
let title: String = MY_CONFIG[path!(title)].into();
assert_eq!("TOML example", title);

// A deeper path.
let owner: &str = MY_CONFIG[path!(server.owner)].into();
assert_eq!("Tom", owner);

// Any numerical types.
let timeout: u32 = MY_CONFIG[path!(server.timeout)].into();
assert_eq!(5000, timeout);
let timeout: f32 = MY_CONFIG[path!(server.timeout)].into();

// A homogeneous array can be accessed as `Vec<T>`.
let ports: Vec<u64> = MY_CONFIG[path!(server.ports)].into();
assert_eq!([8000, 8001, 8002].to_vec(), ports);

Check out more examples for more details about usage.