library-template

A template enumeratio library: figurate numbers, written in Epsil. Copy it to start a library of your own.

symbol
enumeratio.PolygonalNumber(n, sides: 3)	the n-th polygonal number; triangular by default
enumeratio.CenteredPolygonalNumber(n, sides: 3)	the n-th centered polygonal number
enumeratio.PyramidalNumber(n, sides: 3)	the sum of the first n polygonal numbers
enumeratio.StarNumber(n)	the n-th star number, 6n(n − 1) + 1

Using it

The library is its GitHub repository, versioned by its tags; the owner is its namespace. A host reads it through @enumeratio/manifest/libraries, over jsDelivr, fetching only the symbols an expression uses:

import { parseExpression } from "@enumeratio/formats/expression";
import { createRegistryResolver } from "@enumeratio/manifest";
import { catalog, githubHost } from "@enumeratio/manifest/libraries";

const resolver = createRegistryResolver(catalog(["enumeratio/library-template@0.1.0"], { host: githubHost() }));
const { expression } = await resolver.ensure(ce, parseExpression("enumeratio.PolygonalNumber(4, sides: 5)").json);
ce.box(expression).evaluate(); // 22

It's a plain JavaScript library too: dist/index.js exports declare(ce), which declares every symbol into a compute-engine.

Writing one

Each symbol is a folder, reference/<Name>/, holding what you write:

• index.md: front matter (name, summary, the references other sources give it, and its definition) and a markdown body. The definition is Epsil:

  definition:
    signature: "(n: integer, sides: integer?) -> integer"
    body: Sum(enumeratio.PolygonalNumber(k, sides), (k, 1, n))
    defaults:
      sides: "3"

  The signature names each parameter (? makes it an option), the body uses them, and a default is Epsil too. Packing pins every other symbol the body uses: this library's own, and those of the libraries installed beside it; a name nothing installed serves goes in requires, with its pin.

• examples.tsv: one row per example, each with a stable id; they're the install check, so a definition whose examples fail isn't declared;

• notation.json (optional): how it's written, as box templates and LaTeX triggers;

• examples.values.<system>.tsv (optional): each example as another system writes and answers it, for the systems package.json's enumeratio.mappings names.

Packing writes the rest (reference/index.json, each symbol's definition.json, examples.json and mappings.json, and dist/), which you commit, since a tag serves them as they are:

node <enumeratio>/packages/manifest/scripts/pack-library.ts .

with a checkout of enumeratio/enumeratio. In CI, the system's action packs it and checks what's committed is current:

- uses: actions/checkout@v4
- uses: enumeratio/enumeratio/.github/actions/pack-library@<ref>

The ref is the system this library is written against: pin it, and move it when you move to a newer system. Given since:, a checkout of the previous version, the action also checks that the version number says at least what changed: this repository's CI passes it the last tag, so a changed definition can't ship under the same version.