noCopyFilter

A filter for Bruno Dias' Improv engine that will choose groups with non-matching tags or mismatched tags. In other words, this filter rejects groups that have tags which copy any one of the model's tags.

99% of this code is originally by Bruno Dias (https://github.com/sequitur)

Example

const spec = {
  root: {
    groups: [
      {
        tags: [['class', 'mammal']],
        phrases: ['dog']
      },
      {
        tags: [['class', 'bird']],
        phrases: ['parrot']
      },
      {
        tags: [['something', 'else']],
        phrases: ['something else']
      },
    ]
  }
};

const all_results_possible = {};
const first_group_impossible = { tags: [['class', 'mammal']] };

const i = new Improv(spec, {
  filters: [noCopyFilter()]
 });

i.gen('root', all_results_possible) will return dog, parrot or something else. i.gen('root', first_group_impossible) will return parrot or something else but never dog.

What is a "mismatch"

First, a tag is an array of the shape ['String A', 'String B']. Two tags match if String A of Tag 1 and String A of Tag 2 are the same.

• ['String A', 'String B'] and ['String A', 'String C'] match.

Two tags mismatch if they match but String B of Tag 1 and String B of Tag 2 are NOT the same.

• ['String A', 'String B'] and ['String A', 'String C'] mismatch.

Two tags are copies if both String A and String B are the same in both tags.

• ['String D', 'String E'] and ['String D', 'String E'] are copies.

This filter allows for:

1. Groups with tags that don't match.
2. Groups with tags that mismatch

(the first two cases)

This filter blocks:

• Groups with tags that are copies.

(the last case)