Soufflé: Declarative API

[byakuren-hijiri]

It is possible to implement a declarative API that operates of the created Soufflé entities in lambda functions like:

const souffle = souffle(projectName, (s) => {
  const varUse = g.relation('varUse', ['var', 'func']);
  const varDecl = g.relation('varDecl', ['var', 'func']);
  const readOnly = g.relation('readOnly', ['var', 'func'], { io: "output" });
  const readOnlyRule1 = g.rule(
    readOnly,
    { relation: varDecl },
    { relation: varUse, negated: true }
  );
});

Which effectively describes the following Datalog rule and the relations in use:

readOnly(var, func) :-
    varDecl(var, func),
    !varUse(var, func),

[jubnzv]

It would be quite inconvenient to use, because facts and relations are connected to each other. It is much easier to write functions that construct AST within the given context as it implemented here: #120