Thirdparty gproc sub.

pub_sub.erl

-module(pub_sub).

-export([
         sub/1,
         sub/2,
         pub/2
        ]).

sub(Property) ->
    sub(Property, self()).

sub(Property, Pid) ->
    Key = {p, l, Property},
    Value = undefined,
    case gproc_lib:insert_reg(Key, Value, Pid, l) of
        false -> throw({gproc_error, badarg});
        true  -> monitor_pid(Pid)
    end.

monitor_pid(Pid) ->
    case ets:insert_new(gproc, {{Pid,l}}) of
        false -> true;
        true  ->
            gen_server:cast(gproc, {monitor_me,Pid}),
            true
    end.

pub(Property, Msg) ->
    gproc:send({p, l, Property}, Msg).