Reset to default values

[vessd]

I want to handle multiple configurations with the same fields.
I have the default settings and N configuration files. I want to merge the default settings with each file separately and as a result, get N structures with the settings.
How to reset values or parse them using only one source?

let mut config = Config::new();
config
    .set_default("host", "localhost")?
    .set_default("port", 21)?
    .set_default("user_id", 0)?;
config.merge(File::with_name("foo"))?;
let host_foo: Host = config.try_into()?;
config.reset(); // <-- reset to default
config.merge(File::with_name("bar"))?; // merge only with default values
let host_bar: Host = config.try_into()?;

[mehcode]

You can do config2.merge(config1). That would let you keep config1 from mutating.