Can we run Erlog inside IEx?

Yes, erlog runs without problems in IEx. It is basically just a big library and with some interface modules.

• The basic interface is in the :erlog module which you can call from programs or from a shell like IEx. The Erlog state is in a structure which you pass around.
• There is also an Erlog gen_server in the module :erlog_server which you can startup. It manages the state and there is a set of interface functions to access it, basically the same interface as in :erlog.
• You can also start up a simple prolog-like shell with :erlog_shell.

The interface is standard Erlang but this mainly because no-one has shown any interest in writing one for Elixir. It would not be difficult.

Robert

P.S. Saw your question in the irc but hadn’t got around to answering it.

Thank you! Does that mean that the Erlang modules you listed are a part of Erlang and don’t have to be installed on top of the vanilla Erlang?

For the record, I use Erlang/OTP 19.2.

EDIT: I can’t see erlog in Erlang’s website docs, that’s why I am asking if it’s a standalone package that needs to be installed extra. Also, how exactly do I exit the erlog_shell?

No, erlog is a separate system which you will have to down load from github, GitHub - rvirding/erlog: Prolog interpreter in and for Erlang · GitHub , and connect into your application. This can be done with mix (I guess) but I can’t help you there as my knowledge of mix is not great.

How do I connect a downloaded GIT repo to my app in an Erlang environment? If I know that, I can probably infer how to do it with mix.

If you are using rebar3 with erlang you can specify it as a dependency and it will be downloaded and put in a suitable place. Pretty much what mix does. If you are not using rebar3 then you need to download it by hand and put it somewhere that erlang can find it, the easiest is by either using the -pa <dir> flag when starting erlang or by setting ERL_LIBS environment variable, code — OTP 29.0.2 (kernel 11.0.2) . With mix you can also give it as a dependency but you need to tell mix that it is erlang which it must compile and not elixir. i don’t know how you do that.

I’ll figure the mix part out. You helped me a lot, thank you!

No worries, just ask if have more questions about running it. Seriously.

Definitely will, just don’t want to spam you with all of it before even having tried. I’ll be bumping the thread when I get around to actually trying erlog.

No, there should be no problems using erlog from Elixir. The only issue is that the argument order to the functions in some of the interface modules, e.g. erlog, is in the standard Erlang ordering with the state the last argument and not in the standard Elixir ordering. This will make them a little more difficult to use in pipes.

if there is interest I can fix a set of Elixir modules for erlog.

Couldn’t then/2 help in this case?