inline-config

Effortlessly embed config as static data and access with any compatible data structures.

A procedual macro config! is provided to parse sources at compile time, generate static data structures, from which we can access values via the Get trait. The output types of accessed values can be almost "at will", as long as they are compatible.

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 static variable using config! holding the config data

use inline_config::config;

config! {
    // Note, this looks like a typical static item declaration, but the type is omitted.
    // `#[toml]` is needed to specify the format of this source.
    // Including a file from disk is also possible, see `examples/include.rs`
    pub static MY_CONFIG = #[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 Get trait in combination with the path! macro

use inline_config::{Get, path};

// Multiple types may be compatible. As a cost, type annotation is always required.
let title: &str = MY_CONFIG.get(path!(title));
assert_eq!("TOML example", title);
let title: String = MY_CONFIG.get(path!(title));
assert_eq!("TOML example", title);

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

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

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

Check out more examples for more details about usage.