gistfile1.txt

# test/echo_loop.rb
loop do
  puts $stdin.gets
end

# elsewhere
require 'open3'

# this works
stdin, stdout, stderr, wait_thr = Open3.popen3("dc")
loop do
  stdin.puts "2 1 + p"
  res = stdout.gets
  puts res
  sleep 1
end

# this doesn't
stdin, stdout, stderr, waiter = Open3.popen3('ruby test/echo_loop.rb')
stdin.puts 'hello'
res = stdout.gets # hangs here. what am i missing/doing wrong?
                  # i want to stdin.puts "something"
                  # and stdout.gets "something"
                  # for testing shelling out