@extable/sequence

Sequence inference engine for Extable auto-fill.

This package provides a small, composable sequence engine that can detect list patterns, arithmetic/geometric progressions, and structured string patterns (embedded numbers, roman numerals, English ordinals) and then generate subsequent values.

Install

npm install @extable/sequence

Usage

import { inferSequence, createBuiltInRegistry } from "@extable/sequence";

const registry = createBuiltInRegistry(["ja", "en"]);
const seq = inferSequence(["Jan", "Feb"], { registry });

// The iterator yields values *after* the seed.
seq.next().value; // "March"

API

inferSequence

inferSequence(seed: readonly number[], options?: { registry?: SequenceRegistry }): Sequence<number>
inferSequence(seed: readonly Date[], options?: { registry?: SequenceRegistry }): Sequence<Date>
inferSequence(seed: readonly string[], options?: { registry?: SequenceRegistry }): Sequence<string>

Inference priority:

1. Single-item seed -> copy
2. Built-in/custom list match
3. Arithmetic progression
4. Geometric progression (numbers only)
5. Seed repeat

SequenceRegistry

const registry = new SequenceRegistry({ langs: ["ja", "en"] });
registry.register(list);
registry.registerMatch(matcher);

• langs controls language preference (no navigator dependency).
• en is appended if missing.

Built-in Lists

Cycle lists (wrap-around):

• Weekdays (en/ja)
• Months (en/ja, traditional Japanese month names)
• Quarters (en/ja)
• Zodiac animals (十二支)
• Zodiac signs (en/ja)
• Directions (16-wind, en/ja)
• AM/PM (en/ja)
• Seasons (en/ja)
• Solfege (en/ja)
• Rokuyo (六曜)
• Greek letters (en/ja/symbols)

Finite lists (stop at end):

• Ten Heavenly Stems (十干)
• Planets (en/ja, 8 planets)
• Kuji-in (九字)
• Eight virtues (八徳)

Custom Matchers

You can register custom matchers with a score to override built-ins:

registry.registerMatch({
  id: "custom",
  match(seed) {
    if (seed[0] === "A" && seed[1] === "B") return { score: 100 };
    return null;
  },
  createIterator() {
    return {
      next() {
        return { value: "Z", done: false };
      }
    };
  }
});

License

Apache-2.0