First, the boring stuff

NLP

https://en.wikipedia.org/wiki/Natural-language_processing

NLP basics in practice

• Largely statistical
• Lemmatisation
• Part of speech tagging

Example

What can be done with the most common 1000 words

English language facts

https://github.com/spencermountain/compromise/wiki/Justification

Enter compromise.js

https://github.com/spencermountain/compromise/wiki/Justification

Online and offline NLP

But first, a war story

Compromise.js

const sample = `The journey took us through Rome, Madrid and finally, Paris...`;
// The only part that actually matters :)
const places = nlp(sample).places().out('array');
document.querySelector('.out').innerText = places;

// No dice - compromise has no idea what Bitola and Ohrid even mean :)
const sample = "The journey took us through Skopje, Bitola and finally, Ohrid..."; 
const places = nlp(sample).places().out('array');
document.querySelector('.out').innerText = places;

Stuff compromise.js can do

• Verb analysis (tense)
• Noun analysis (singular / plural, place, name, organization, unit...)
• Dates, Numbers, Values
• Tags
• Transformations

http://compromise.cool/

Stuff compromise.js sucks at

Now, for something (hopefully) cool

a short demo:

https://beerbot.darko.io

import nlp from 'compromise';
import skills from './skills/'; // a skill - something that the bot knows how to do
import { get, set } from 'lodash';

const getReply = async (input) => {
  const skillMatch = skills.find((s) => {
    const rules = s.matchRules; // each skill comes with match rules
    const ruleMatch = s.matchRules.find(
      r => nlp(input).normalize().match(r).found
    ); // we look through a skill's match rules, and look for one that 
       // works with the given input

    if (ruleMatch) { // we return the first match we find
      return true;
    }
  });

  console.log(nlp(input).debug()); // VERY useful debugging info
  if (skillMatch) {
    // keep some history, for more fancy stuff
    const topicHistory = get(context, 'topics') || [];
    topicHistory.push(skillMatch.ID);
    set(context, 'topics', topicHistory);
    // reply = a function that gets executed on a skill match
    const reply = await skillMatch.reply(input, context); 
    return reply;
  } else {
    // Otherwise, fall back to something really basic
    return { mode: 'text', value: 'Hi there!' };
  }

};

import { set, get, random } from 'lodash';

const ID = 'greet'; // The name of the skill

const lexicon = {}; // Custom lexicon / tagging if we happen to need it

// Rule(s) to match input against
// Simple lookup, tagging, logic + full support for regex
const matchRules = [
  '(hi|hello|ahoy|greetings|#Expression) bot?'
];

// Some replies to return
const replies = [
  () => ({ mode: 'text', value: 'Hi there.' }),
  () => ({ mode: 'text', value: 'What\'s up?' }),
];

const reply = (input, context) => {
  // Store some metadata to localStorage
  const timesMatched = get(context, 'greet.matched', 0);
  set(context, 'greet.matched', timesMatched + 1);
  localStorage.setItem('bjs-bot-context', JSON.stringify(context));

  // get a random-ish reply, to avoid being very repetitive
  const replyRoll = random(0, replies.length - 1);

  return replies[replyRoll](input, context); // Return said reply
};

// Export stuff
export default { ID, lexicon, matchRules, reply };

or, how to make a weather skill