Function extract_string

pub fn extract_string<T: Serialize, P: IqPath>(
    source: &T,
    path: P,
    format: IqFormat,
) -> Option<String>

Extract a string from a structure at a given path, with a given format.

If the path is not found, or empty, return None.

This function also returns None if the the Serialize implementation fails, which should not happen with a standard implementation.