3 /// `.proto` file syntax.
5 pub enum Syntax {  enum
6     /// `syntax = "proto2"`.
8     /// `syntax = "proto3"`.
12 impl Syntax {  impl
13     pub(crate) fn parse(syntax: &str) -> Option<Syntax> {  in parse()  argument
14         match syntax {  in parse()
15             "" | "proto2" => Some(Syntax::Proto2),  in parse()
16             "proto3" => Some(Syntax::Proto3),  in parse()
21     pub(crate) fn of_file(file: &FileDescriptorProto) -> Syntax {  in of_file()  argument
22         Syntax::parse(file.syntax()).unwrap_or(Syntax::Proto2)  in of_file()