I wrote an MSc thesis a long time ago exactly about the question you asked, it is titled "Committed-Choice Programming Languages", you may find it helpful. Download link below:

https://1drv.ms/b/c/987ed5526a078e8f/EY-OB2pS1X4ggJiMEwAAAAABv08vK5GeA6Ci6F8IZ44wlA?e=GqRGM5

I thought Prolog and the 5th Generation Programming Project was dead a long time ago. I am bemused to see interest in this subject.