Macro impl_figment_convert

macro_rules! impl_figment_convert {
    ($name:ty) => { ... };
    ($name:ty, $start:ident $(, $more:ident)*) => { ... };
    ($name:ty, self, $start:ident $(, $more:ident)*) => { ... };
}

A macro to implement converters from a type to Config and [figment::Figment].

This can be used to remove some boilerplate code that’s necessary to add additional layer(s) to the Config’s default Figment.

impl_figment takes the default Config and merges additional Provider, therefore the targeted type, requires an implementation of figment::Profile.

Example

Use impl_figment on a type with a root: Option<PathBuf> field, which will be used for Config::figment_with_root().

use std::path::PathBuf;
use serde::Serialize;
use foundry_config::{Config, impl_figment_convert};
use foundry_config::figment::*;
use foundry_config::figment::error::Kind::InvalidType;
use foundry_config::figment::value::*;
#[derive(Default, Serialize)]
struct MyArgs {
    #[serde(skip_serializing_if = "Option::is_none")]
    root: Option<PathBuf>,
}
impl_figment_convert!(MyArgs);

impl Provider for MyArgs {
    fn metadata(&self) -> Metadata {
        Metadata::default()
    }

    fn data(&self) -> std::result::Result<Map<Profile, Dict>, Error> {
        let value = Value::serialize(self)?;
        let error = InvalidType(value.to_actual(), "map".into());
        let mut dict = value.into_dict().ok_or(error)?;
        Ok(Map::from([(Config::selected_profile(), dict)]))
    }
}

let figment: Figment = From::from(&MyArgs::default());
let config: Config = From::from(&MyArgs::default());

 // Use `impl_figment` on a type that has several nested `Provider` as fields but is _not_ a `Provider` itself

#[derive(Default)]
struct Outer {
    start: MyArgs,
    second: MyArgs,
    third: MyArgs,
}
impl_figment_convert!(Outer, start, second, third);

let figment: Figment = From::from(&Outer::default());
let config: Config = From::from(&Outer::default());