Sample that demonstrates how to generate Datalog with new Java API.

output.logic

parent(a, b) ->
    string(a),
    string(b).

ancestor(a, b) ->
    string(a),
    string(b).

ancestor(a, c) <-
    parent(a, b).

ancestor(a, c) <-
    ancestor(a, b),
    ancestor(b, c).

sample.java

DatalogEnv env = new DatalogEnv();
env.addClause(constraint(
        singleAtomList("parent", "a", "b"), // ->
        conList(atom("string", "a"),
                atom("string", "b"))));
env.addClause(constraint(
        singleAtomList("ancestor", "a", "b"), // ->
        conList(atom("string", "a"),
                atom("string", "b"))));
env.addClause(rule(
        singleAtomList("ancestor", "a", "c"), // <-
        singleAtomList("parent", "a", "b")));
env.addClause(rule(
        singleAtomList("ancestor", "a", "c"), // <-
        conList(atom("ancestor", "a", "b"),
                atom("ancestor", "b", "c"))));

env.validateEnv();

System.out.println(env.toString());