ruby/pty interaction with octave in real-time

octave_pty.rb

require 'pty'

def till_prompt(cout)
    buffer = ""
    loop { buffer << cout.getc.chr; break if buffer =~ /octave:.*>/ }
    return buffer
end

def octave(string)
    @octave_in.printf("#{string}\n")
    puts till_prompt(@octave_out)
end

@octave_out, @octave_in, @pid = PTY.spawn("octave")
printf till_prompt(@octave_out)