# Python interface (Janus) for Prolog 10?

**URL:** <https://swi-prolog.discourse.group/t/python-interface-janus-for-prolog-10/9547>\
**Category:** Data Structure\
**Created:** [March 16, 2026, 6:23pm UTC](https://swi-prolog.discourse.group/t/python-interface-janus-for-prolog-10/9547 "2026-03-16T18:23:54Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![AZH](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/azh/32/6831_2.png) [@AZH](https://swi-prolog.discourse.group/u/AZH)\
**Post date:** [March 16, 2026, 6:23pm UTC](https://swi-prolog.discourse.group/t/python-interface-janus-for-prolog-10/9547/1 "2026-03-16T18:23:54Z")

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Hi there, anyone successfully call Prolog 10 from Python using Janus?

Janus worked fine with Prolog 9.3, but after upgrading to Prolog 10.0.1, apparently it still tries to locate ```/Applications/SWI-Prolog.app/Contents/Frameworks/libswipl.9.dylib```, which no longer exists.

Wonder if there is a quick fix for this? Thanks a lot!!

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**Author:** ![jan](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jan/32/4_2.png) [@jan](https://swi-prolog.discourse.group/u/jan)\
**Post date:** [March 17, 2026, 9:21am UTC](https://swi-prolog.discourse.group/t/python-interface-janus-for-prolog-10/9547/2 "2026-03-17T09:21:04Z")

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How did you install Prolog and Janus. Looks like you are running a Janus for the old version with the new version. Just re-installing should help then, a little depending on how it was installed in the first place.

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**Author:** ![AZH](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/azh/32/6831_2.png) [@AZH](https://swi-prolog.discourse.group/u/AZH)\
**Post date:** [March 17, 2026, 2:19pm UTC](https://swi-prolog.discourse.group/t/python-interface-janus-for-prolog-10/9547/3 "2026-03-17T14:19:12Z")

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Many thanks Jan!  
I have reinstalled Janus (latest version 1.5.2), also rebooted MacOS, but the issue remains the same. Looks like some hidden setting that points to `…/libswipl.9.dylib` did not get updated by the reinstallation.  
What other things I could try?

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**Author:** ![jan](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jan/32/4_2.png) [@jan](https://swi-prolog.discourse.group/u/jan)\
**Post date:** [March 18, 2026, 9:20am UTC](https://swi-prolog.discourse.group/t/python-interface-janus-for-prolog-10/9547/4 "2026-03-18T09:20:59Z")

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The link to the version 9 file comes from linking the Python plugin with an old version of SWI-Prolog. So, if you install Janus as PIP package from source (AFAIK there is no binary for MacOS), it somehow finds version 9 and links to that. If I recall well, it tries to run `swipl` to find the location and configuration of Prolog. So, make sure `swipl` runs the right version. Also make sure there are no left overs of the old Janus package.

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**Author:** ![AZH](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/azh/32/6831_2.png) [@AZH](https://swi-prolog.discourse.group/u/AZH)\
**Post date:** [March 18, 2026, 1:55pm UTC](https://swi-prolog.discourse.group/t/python-interface-janus-for-prolog-10/9547/5 "2026-03-18T13:55:19Z")

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Ah, you’re spot on!  
Turns out it was because `pip install janus-swi` by default reused the cached Janus package instead of downloading a fresh one.  
So I use `pip cache purge` to clear out everything, then `pip install janus-swi` again. Now all works perfectly!|  
Thank you so much, Jan!