communication with Rserve (R TCP server) with gen_tcp

[Stefan Houtzager]

I'm a developer learning elixir, I would like to be able to execute R functions from elixir. I heard it is possible with Rserve (https://rforge.net/Rserve/example.html) and erlang gen_tcp. My first problem is how to send R calls (I'm not familiar with R myself by the way, but a collegue should help me with that). For example (elixir code):

Erlang/OTP 19 [erts-8.0] [source-6dc93c1] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]

Interactive Elixir (1.3.0) - press Ctrl+C to exit (type h() ENTER for help)

iex(1)> {:ok, socket} = :gen_tcp.connect('rserve.bpmdemo.com', 6311, [active: false])

{:ok, #Port<0.1200>}

iex(2)> :gen_tcp.send(socket, 'rnorm(100)')

:ok

iex(3)> {:ok, msg} = :gen_tcp.recv(socket, 0)

{:ok,

 [82, 115, 114, 118, 48, 49, 48, 51, 81, 65, 80, 49, 13, 10, 13, 10, 45, 45, 45,

  45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 13, 10, 2, 0, 1, 66, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0]}

iex(4)> :gen_tcp.close(socket)

:ok

iex(5)> {:ok, socket} = :gen_tcp.connect('rserve.bpmdemo.com', 6311, [active: false])

{:ok, #Port<0.1253>}

iex(6)> :gen_tcp.send(socket, 'as.integer(20/10)')

:ok

iex(7)> {:ok, msg} = :gen_tcp.recv(socket, 0)

{:ok, 'Rsrv0103QAP1\r\n\r\n--------------\r\n'}

iex(8)> :gen_tcp.close(socket)

:ok

The string Rsrv0103QAP1\r\n\r\n--------------\r\n   returned by the call on iex(7)> seems from Rserv.c (https://github.com/s-u/Rserve/blob/master/src/Rserv.c).

What am I missing?