tribles-deno

This is the deno implementation of the tribles ecosystem.

It is still in early development.

Status

So far the following components have been implemented.

• PART js implementation.
• TribleDB js immutable trible database.
• TribleKB js immutable trible knowledge-base.
• Core types:
  • UUID
  • Shortstring
  • Longstring
  • Spacetimestamp
  • float64

Currently to be done and missing is:

• PART rust implementation.
• TribleDB rust implementation.
• TribleMQ js middleware communications libary.
• JS Ontology tools to dynamically load TribleKB contexts and documentation from Trible based ontologies.
• Core number types.
• More types…
• Even more types…
• An ontology describing everything.

Elevator Pitch

Many modern applications from chatbots and robots to project management applications and wikis have the need for some form of flexible knowledge represenation, that goes beyond the capabilities of traditional RDBMS. However existing technologies like the Semantic Web with its RDF, SPARQL, jsonLD, and OWL based standards are too complex, and transitively rely on further complexity from other web standards. This results in few implementations, which are often incomplete and infrequently maintained. However, the theoretical foundations and ideas of these standards are often good and sound, what we need is “Semantic Web, the good parts”. What we need is the linked list of knowledge representation. [1]

Example: Todo List

import {
  assertArrayIncludes,
  assertEquals,
} from "https://deno.land/std@0.75.0/testing/asserts.ts";
import { v4 } from "https://deno.land/std@0.76.0/uuid/mod.ts";

import { id, TribleKB, types } from "../mod.js";

Deno.test("Integration", () => {
  const observation_attr = v4.generate();
  const state_open = v4.generate();
  const state_done = v4.generate();

  // Define a context, mapping between js data and tribles.
  const todo_ctx = {
    [id]: { ...types.id, id: v4.generate() },
    observationOf: {
      isLink: true,
      id: observation_attr,
    },
    observedAs: {
      isInverseLink: true,
      id: observation_attr,
    },
    task: {
      ...types.shortstring,
      id: v4.generate(),
    },
    state: {
      isLink: true,
      id: v4.generate(),
    },
    stamp: {
      ...types.spacetimestamp,
      id: v4.generate(),
    },
    createdBy: {
      isLink: true,
      id: v4.generate(),
    },
    name: {
      ...types.shortstring,
      id: v4.generate(),
    },
  };
  const kb = new TribleKB();

  // Add some data.
  const observation_id = v4.generate();
  let todos = new TribleKB().with(todo_ctx, ([t]) => [
    {
      task: "Get almondmilk!",
      observedAs: [
        {
          [id]: observation_id,
          state: state_open,
          stamp: { t: 0n, x: 0n, y: 0n, z: 0n },
        },
      ],
      createdBy: { name: "jp" },
    },
  ]);

  // Query some data.
  const [first_result] = todos.find(
    todo_ctx,
    ({ observation, stamp, task }) => [
      {
        [id]: observation.walk(), //Walk will create a proxy object which allows us to navigate the graph as a JS tree.
        stamp: stamp.at(0),
        observationOf: { task, createdBy: { name: "jp" } },
      },
    ],
  );

  assertEquals(first_result.observation.state[id], state_open); //Notice the walk() in action.
  assertEquals(first_result.task, "Get almondmilk!");
  assertEquals(first_result.stamp, { t: 0n, x: 0n, y: 0n, z: 0n });
});

Background and Fundamentals

Triples and Tribles (and Blobs)

The fundamental building block of the tribles ecosystem is the trible. Tribles, are binary triples, encoded as 64byte long immutable values, that consists of three parts, an entity, an attribute, a value, or to use their semantic web names, a subject, a predicate, and an object. Entity and attribute are both 16byte wide, and hold a random or pseudorandom identifier like a UUID. [2] The value is 32byte wide and can hold arbitrary data. Any data longer than 32byte is hashed with a function of the users choice, e.g. blake2s, and stored as a blob. This separation of long and short data has a few advantages:

• It makes storing large binary data trivial.
• It allows for the system to eagerly share knowledge about this data, while being lazy about performing the actual transfer.
• It allows for interesting optimisations when indexing the now fixed size tribles.

The lengths of E,A, and V were chosen so that the frequency of collisions in IDs or Hashes is far less likely than the system producing bad data from CPU errors. [3]

TribleDB and TribleKB

Tribles are stored in TribleDB, a persistent (not in the durable, but immutable sense), append only, in memory database. It provides conjunctive queries and constraint solving over tribles, but is completely limited to binary data.

Datalog like conjunctive queries are great if your language is build around hypergraphs, e.g. Prolog. Alas most languages we use today are build around trees, and therefore profit from languages that return trees or tree unfoldings of graphs. A good example for this is GraphQL, although it is more of a RPC tool than a query language. JSON-LD is another candidate, and while we found the static conversions of JSON data to be cumbersome, we’ve adapted many concepts from it.

TribleDB is therefore wrapped by TribleKB, which performs conversions between JS Objects and trible data, provides tree interfaces for data insertion, and tree based query capabilites, as well as tree-based graph walking capabilites, all operating over familiar plain old javascript objects (and proxies cough).

Contexts, Types and Ontologies

The thing that JSON-LD realy got right, is their decoupling of the underlying data representation (in their case RDF) and the user facing representation. If different systems are to exchange information, or if a single system is upgraded, there needs to be some form of neutral representation, in our case bytes. By giving the user the ability to provide contexts in which the underlying tribles can be interpreted as needed, we can:

• Provide easy upgrade paths for legacy systems. Old parts can read old representations, new parts can read new representations, or a mix thereof.
• Decouple programming language types from value types. E.g. a timestamp can be read as different date types in the same query.
• Allow the user to use approprate, self explanatory, names. One programmers legacy_date is another programmers sanity_check_date.
• Allow users to fix past mistakes or missunderstandings. Whenever a name in OWL is used it’s used. Trible don’t care about names, only about IDs.

Typing has drawn heavy inspiration from RDFS, in that the type of a value (the meaning of the layout of bytes, not the represenation in a programming language) is only depending on the attribute itself. With one type per attribute id. This has the advantage of giving statically typed programming languages like Rust the ability to properly type queries with the help of statically generated contexts.

The above information is itself stored as tribles in the form of an ontology. You can think of it as a schema in an RDBMS, with the addition of it also containing documentation and meta information.

• [1] Lispers will probably argue that the linked list is the linked list of knowledge representation.
• [2] Someone with an RDF background might recognize these as skolemized blank-nodes.
• [3] Unless maybe you’re using a system with redundant CPUs, e.g. Rocket Control. In which case: “Why does your rocket need a knowledge base!!??”