Service call failed in json-prolog while querying an owl file in Cram

Question

Hi,

I started a roslisp node in cram and have json-prolog query services (i can see

/json_prolog/finish
/json_prolog/next_solution
/json_prolog/query
/json_prolog/simple_query

when i do "rosservice list").

Also by typing (json-prolog:check-connection) i receive T. so i assume that everything set up properly.

problem is when i try any query like

(json-prolog:prolog '("rdf_has" ?owlname "http://knowrob.org/kb/srdl2-comp.owl#urdfName" ("literal" ?var)))

i receive

Prolog query failed: Got error: The value
             |'["rdf_has",{"variable":"OWLNAME"},"http://knowrob.org/kb/srdl2-comp.owl#urdfName",{"term":["literal",{"variable":"VAR"}]}]'|
           is not of type
             LIST..

also i have

[(JSON-PROLOG) WARN] 1505226166.532: Service call failed. 
[(JSON-PROLOG) WARN] 1505226166.532: Retrying...

Thanks

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Originally posted by aAsoodeh on ROS Answers with karma: 3 on 2017-09-13

Post score: 0

Answer 1

Hi,

This seems like an error on the KnowRob side. I execute it on my machine and it works fine. I'm using the master branch of KnowRob (on 14.04), the latest commit I have is from 3rd of September. And I'm using the latest version of cram_json_prolog, master branch, last commit was on 26 June. Try prolog-simple or a simpler query in general.

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Originally posted by gaya with karma: 311 on 2017-09-13

This answer was ACCEPTED on the original site

Post score: 0

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Original comments

Comment by aAsoodeh on 2017-09-13:
same error when trying prolog-simple. do you know any cram project that i can use as pattern to build a clear project? any tutorial? Thanks

Comment by gaya on 2017-09-18:
We have a bunch of tutorials. Here is he one that showcases most complex behaviors It runs on the newest CRAM version (0.4.0). Consult the installation page to get the latest version.