ROSLisp Tutorial Error in add-two-ints
I have what seems to be a completely standard ROSLisp configuration. I have the talker and listener tutorials working; in fact so does the add-two-ints-server, but the add-two-ints-client script triggers an error in SBCL:
The symbol "ADD-TWO-INTS-CLIENT-MAIN" is not external in the ROSLISP-TUTORIALS-BASICS package.
The script looks fine:
(ros-load:load-system "roslisp_tutorials_basics" "roslisp-tutorials-basics")
(roslisp-tutorials-basics:add-two-ints-client-main)
So I´m guessing that there is a manipulation of the package environment somewhere deep in the ROS libraries that may not work on every system. These guys on the Web discovered a pretty subtle bug that caused similar behavior. They said:
(DEFVAR *BUILT-IN-PACKAGES* (MAPCAN (LAMBDA (PACK) (CONS (PACKAGE-NAME PACK) (PACKAGE-NICKNAMES PACK))) (LIST-ALL-PACKAGES)))You are destructively changing the package-nicknames list of PACK. Don't do that.
Changing this to:
(defvar *built-in-packages* (mapcan (lambda (pack) (cons (package-name pack) (copy-list (package-nicknames pack)))) (list-all-packages)))makes the problem go away.
Is it possible that having quicklisp installed would conflict with ROS? I´m at SBCL 1.3.1. Is it advised to upgrade?
-T
'these guys'?
Looking at the responses to other Lisp related questions, I have the feeling that the ROSLisp community isn't very large (any more). It might take some time before you get a reply.
It would be very nice if you could report back on any solution/work-around you find. That would help immensely.
Could you please point at the particular part of the roslisp tutorial from the ROS wiki page when this error happens? I suspect that you are not following the tutorial.
The problem that you encountered is a minor issue, I doubt greatly that it is connected to an SBCL bug.
I did another pull of the add-two-ints tutorial and it worked. By the way, I was not implying that there was a bug in SBCL. It´s just that I´m really putting the configuration of Lisp through a lot while doing other experiments. You saved me again. How do I close this?
You could accept the answer by @gaya by ticking the checkmark to the left of the answer. That would mark the question as answered.
We don't typically close questions here on ROS Answers. Marking the question as answered is much more visible from the question list.