Function from_reader 

pub fn from_reader<S, R>(reader: R) -> Result<S>
where
    S: Syn,
    R: Read,

Available on crate feature json only.

Deserialize an instance of Syn type from an I/O stream of JSON.

This function is equivalent to the following code:

use syn_serde::Syn;

let adapter: <syn::File as Syn>::Adapter = serde_json::from_reader(reader)?;
let syn_file = syn::File::from_adapter(&adapter);
Ok(syn_file)