This is a Mercury backend for the Google protocol buffers compiler.
What it does
Protocol buffers allow you to define an extensible binary protocol format in a language-independent .proto file. The protocol buffer compiler then compiles your .proto file into one of several target languages. The generated API gives you a type-safe way to read or write messages in your protocol using your preferred language(s).
This extension generates a Mercury API for a protocol defined in a .proto file.
Example
Say you define the following protocol in person.proto:
enum Gender {
MALE = 0;
FEMALE = 1;
}
enum MaritalStatus {
MARRIED = 0;
SINGLE = 1;
}
message Person {
required int32 id = 1;
required string name = 2;
required Gender gender = 3;
required double double= 4;
optional string email = 5;
optional MaritalStatus marital_status = 6 [default = SINGLE];
repeated Person children = 7;
}Then you can generate the Mercury module person.m with the command:
mprotoc person.proto --out .
The generated module will contain the following types and functions:
:- type person
---> person(
person_id :: int,
person_name :: string,
person_gender :: gender,
person_double :: float,
person_email :: maybe(string),
person_marital_status :: maybe(marital_status),
person_children :: list(person)
).
:- func person_email_or_default(person) = string.
:- func person_marital_status_or_default(person) = marital_status.
:- type gender
---> gender_male
; gender_female.
:- type marital_status
---> marital_status_married
; marital_status_single.You can write values of type person to binary streams. For example:
Person = person(
1, "Peter Pan", gender_male, 1.8, yes("pp@neverland.org"), no,
[
person(2, "Peter Pan Jnr.", gender_male, 0.5, no,
yes(marital_status_single), [])
]),
stream.put(pb_writer(Stream), pb_message(Person), !IO),You can also read values of type person from binary streams. For example:
stream.get(pb_reader(Stream, 10000), GetRes, !IO),
( GetRes = ok(pb_message(Person)),
% Do something with Person...
