Top-level statements

In this section, we will see all the top-level statements in the order they should appear in a proto file according to the Protobuf Style Guide (https://protobuf.dev/programming-guides/style/). We are going to go through their meaning, and we are going to see some simple examples.

Syntax

The syntax statement is one of the easiest statements to understand. This tells the compiler (protoc) the version we are using in the file and, therefore, the features we can and cannot access:

EBNF – Syntax statement

version = "proto2" | "proto3" | "editions"
syntax = "syntax" "=" ("'" version "'" | '"' version '"') ";"

As you can see, there are three versions that we can pass to the syntax statement:

• proto2
• proto3
• editions

Now, all of this is a little bit obscure, and these names, especially proto2 and proto3, are...