bouncer method

bouncer_method.rb

# Method whose job is to raise or do nothing 
def check_child_exit_status
  result = yield
  status = $? || OpenStruct.new(:exitstatus => 0)
  unless [0,172].include?(status.exitstatus)
    raise ArgumentError, 
          "Command exited with status #{status.exitstatus}"
  end
  result
end

# Before:
@io_class.popen(command, "w+") # ...
# ...
if $? && ![0,172].include?($?.exitstatus)
  raise ArgumentError, 
        "Command exited with status #{$?.exitstatus.to_s}"
end

# After:
check_child_exit_status {
  @io_class.popen(command, "w+") # ...
}