Building a sample (micro) service in Prolog

Sometimes ago I read that some components of IBM Watson were implemented in prolog . So I decided to look at it again after many years… I like Prolog, I studied prolog at Computer Science University of Milan and for my thesis I wrote code in Prolog (and Lisp).

proloGraph is a simple example of howto exposing a prolog graph database to other applications,  building a REST web service. I used swi-prolog and its http library

Install the prolog language (I used the fantastic Linux Debian distribution) with

apt-get install swi-prolog

clone my git repository

git clone
cd proloGraph

Run it with

swipl -s -g 'server(8765).'

Open the following url with your browser


and you will get:

  "prev": [ {"from":"user(gabriele)", "to":"user(matteo)", "rel":"follow"} ],
  "next": [
    {"from":"user(matteo)", "to":"user(ele)", "rel":"follow"},
    {"from":"user(matteo)", "to":"user(gabriele)", "rel":"follow"},
    {"from":"user(matteo)", "to":"user(4)", "rel":"follow"},
    {"from":"user(matteo)", "to":"country(italy)", "rel":"lives"},
    {"from":"user(matteo)", "to":"hobby(running)", "rel":"likes"}