🚀 Release 0.8.3

The agent-side LSP extension is declared in `.pi/settings.json`, not in
`package.json`, so neither `npm update` nor `maintain:outdated` sees it.
Bump it with `pi install npm:@spences10/pi-lsp@0.0.47 -l`, which
rewrites the pin and refreshes the gitignored `.pi/npm/` install cache,
then reformat the file: pi writes it back in its own two-space style,
which `check:oxfmt` rejects.

0.0.47 bounds the project-binary trust prompt — it follows tool
cancellation and times out after 30 s, returning a tool error instead of
leaving the session stuck in `Working`, and an allow-once decision now
survives an idle language-server restart. The read-only usage and the
`tsc --lsp` wiring are unchanged, so `development/tooling.md` only moves
the recorded version. No changelog note: the pin is agent tooling, not
shipped code, as when it was adopted (863198d).

The running pi session still has 0.0.46 loaded; restart pi to pick up
the new version.

.pi/settings.json

@@ -1,3 +1,3 @@
 {
-    "packages": ["npm:@spences10/pi-lsp@0.0.46"]
+    "packages": ["npm:@spences10/pi-lsp@0.0.47"]
 }

AGENTS.md

@@ -7,7 +7,7 @@ first-action facts. Do not restate evolving prose here — it will drift.
 
 ## First action
 
-- Project: F#-style pattern matching for TypeScript/ESM. Node `>=26` (pinned via `.node-version`), ESM-only (no CommonJS shim).
+- Project: pattern matching for TypeScript/ESM. Node `>=26` (pinned via `.node-version`), ESM-only (no CommonJS shim).
 - **While iterating:** `npm run test` (`check:tsc` + the unit suite) for fast feedback on the files you changed.
 - **Optional code intelligence:** this repo installs `@spences10/pi-lsp` (pinned in `.pi/settings.json`) as a project-local pi extension. It talks to the repo's own TypeScript 7 via `tsc --lsp --stdio` and exposes **read-only** tools — `lsp_hover`, `lsp_definition`, `lsp_references`, `lsp_find_symbol`, `lsp_document_symbols`, `lsp_diagnostics(_many)`. **When you are looking for a symbol, reach for the LSP before `rg`/`grep`** — `lsp_references` / `lsp_find_symbol` / `lsp_definition` / `lsp_document_symbols` are semantic and cross-file, so they see shadowing, imports and overloads that a text search cannot; use `lsp_hover` to read inferred types on generic-heavy code. Use `rg` for what the LSP cannot see — doc prose, string literals, config, task lists, file discovery — and reconcile the two sets before editing (symbols from the LSP, strings and prose from `rg`). It has no rename / code-action / apply-edit surface — the write side is pi's `edit` tool + `check:tsc`. Treat empty LSP output as _inconclusive_, not success: **`npm run test` / `npm run verify` remain the sole authoritative gate** (see the next bullet). The server keeps running across that gate with a ~5 min idle timeout and registers no file watchers, so if you change `tsconfig.json` / `package.json` mid-session its diagnostics can be stale — when LSP output disagrees with `check:tsc`, trust `check:tsc` and restart pi (or wait out the idle timeout) before concluding the LSP is wrong.
 - **Definition of done — run this before you call the work finished:** `npm run verify`. If all green, commit. If red, look at the output, fix the root cause, and re-run.

CHANGELOG.md

@@ -7,10 +7,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-- document the public API in the README: the four factories, when to use each,
-  what the `W` (widening) suffix means, and examples that bind the handler-map
-  function once
+## [0.8.3] - 2026-09-28
+
+- upgrade dependencies: oxfmt 0.71 (the only range widened), oxlint 1.86,
+  oxlint-tsgolint 7.0.2003, cspell 10.3.5 and the rest within their existing
+  ranges; no rule or format fallout
+- prune the completed items from the backlog; their rationale already lives in
+  the README, `development/` and the released changelog entries
+
+## [0.8.2] - 2026-09-25
+
+- write the README's Synopsis and Examples sections
+- document the public API in the README
 - add TSDoc to the four public matcher factories
+- document alternatives
 
 ## [0.8.1] - 2026-09-23
 
@@ -106,7 +116,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - basic setup
 
-[Unreleased]: https://gitea.e1nsnull.de/tmu/tiny-pattern-ts/compare/0.8.1...main
+[Unreleased]: https://gitea.e1nsnull.de/tmu/tiny-pattern-ts/compare/0.8.3...main
+[0.8.3]: https://gitea.e1nsnull.de/tmu/tiny-pattern-ts/compare/0.8.2...0.8.3
+[0.8.2]: https://gitea.e1nsnull.de/tmu/tiny-pattern-ts/compare/0.8.1...0.8.2
 [0.8.1]: https://gitea.e1nsnull.de/tmu/tiny-pattern-ts/compare/0.8.0...0.8.1
 [0.8.0]: https://gitea.e1nsnull.de/tmu/tiny-pattern-ts/compare/0.7.1...0.8.0
 [0.7.1]: https://gitea.e1nsnull.de/tmu/tiny-pattern-ts/compare/0.7.0...0.7.1

README.md

@@ -1,15 +1,55 @@
 # tiny-pattern-ts
 
-Pattern matching for TypeScript/ESM environments (F#-style, not regex).
+Exhaustive, type-safe pattern matching for TypeScript.
+
+## Synopsis
+
+```ts
+import { getTaggedUnionMatcher } from "tiny-pattern-ts";
+
+// 1. We have a union type
+type Contact =
+    | { kind: "email"; address: string }
+    | { kind: "phone"; number: string }
+    | { kind: "messenger"; username: string };
+
+// 2. Create a matcher providing the discriminant property
+const matchContact = getTaggedUnionMatcher<Contact>()("kind");
+
+// 3. Define handlers for each branch of the union
+const formatContact = matchContact({
+    email: (e) => `MAIL: ${e.address}`,
+    phone: (p) => `PHONE: ${p.number}`,
+    messenger: (m) => `MESSENGER: @${m.username}`,
+});
+
+// 4. Call the matcher with a value
+const mailOutput = formatContact({ kind: "email", address: "ada@example.com" });
+assert.equal(mailOutput, "MAIL: ada@example.com");
+
+const phoneOutput = formatContact({ kind: "phone", number: "+1 555 0100" });
+assert.equal(phoneOutput, "PHONE: +1 555 0100");
+```
 
 ## Description
 
-`tiny-pattern-ts` brings F#-style pattern matching to TypeScript. Patterns are
-ordinary objects whose `matches` method is a TypeScript type guard, so narrowing
-composes the way any other guard does. It is deliberately not a regex engine and
-not a macro: there is no transpiler and no DSL to learn, and the type-level
-contract is the feature — see [development/library.md](./development/library.md)
-for the design decisions and [Caveats](#caveats) for the limits.
+`tiny-pattern-ts` is a pattern-matching library for TypeScript.
+
+The main goal of `tiny-pattern-ts` is to make pattern matching type-safe with a
+lean syntax. This is accomplished by being exhaustive and passing typed
+parameters per branch to the handlers — supported by an outstanding
+autocomplete and a tiny footprint. The matchers are data last and pipe-friendly:
+build the handler map once, then apply the resulting matcher to values
+(`match(value)`, or `pipe(value, match)`).
+
+See [development/library.md](./development/library.md) for the design decisions
+and [Caveats](#caveats) for the limits.
+
+## Installation
+
+```sh
+npm install tiny-pattern-ts
+```
 
 ## Requirements
 
@@ -19,6 +59,100 @@ for the design decisions and [Caveats](#caveats) for the limits.
   both resolve on TS >= 5.0 in `node10` / `node16` / `nodenext` / `bundler`.
 - The package is **ESM-only** (no CommonJS shim).
 
+## Examples
+
+A few real-world recipes. Each binds the handler-map function once and reuses
+it, so the matcher is allocated a single time.
+
+### Dispatch on a primitive union
+
+A result code is itself a finite union, so `getPrimitiveUnionMatcher` keys a
+handler on each member:
+
+```ts
+import { getPrimitiveUnionMatcher } from "tiny-pattern-ts";
+
+type ResultCode = "ok" | "created" | "no-content";
+
+const toStatus = getPrimitiveUnionMatcher<ResultCode>()({
+    ok: () => 200,
+    created: () => 201,
+    "no-content": () => 204,
+});
+
+assert.equal(toStatus("ok"), 200);
+assert.equal(toStatus("created"), 201);
+assert.equal(toStatus("no-content"), 204);
+```
+
+### Leave cases to a fallback
+
+Pass a fallback as the second argument to handle only part of the universe; it
+receives the members the map leaves uncovered — here the parameter is
+`"deprecated" | "gateway-timeout"`:
+
+```ts
+import { getPrimitiveUnionMatcher } from "tiny-pattern-ts";
+
+type Status = "active" | "beta" | "deprecated" | "gateway-timeout";
+
+const rollout = getPrimitiveUnionMatcher<Status>()(
+    { active: () => "enabled", beta: () => "enabled" },
+    (status) => `blocked (${status})`,
+);
+
+assert.equal(rollout("active"), "enabled");
+assert.equal(rollout("deprecated"), "blocked (deprecated)");
+```
+
+### Dispatch on a property union
+
+The value does not have to be the union itself. When a single property carries a
+finite union, the tagged-union matcher keys on it and narrows the whole record to
+the selected value:
+
+```ts
+import { getTaggedUnionMatcher } from "tiny-pattern-ts";
+
+interface Invoice {
+    readonly currency: "eur" | "usd" | "jpy";
+    readonly amount: number;
+}
+
+const matchCurrency = getTaggedUnionMatcher<Invoice>()("currency");
+
+const symbolOf = matchCurrency({
+    eur: (i) => `€${i.amount.toFixed(2)}`,
+    usd: (i) => `$${i.amount.toFixed(2)}`,
+    jpy: (i) => `¥${i.amount.toFixed(0)}`,
+});
+
+assert.equal(symbolOf({ currency: "usd", amount: 12.5 }), "$12.50");
+assert.equal(symbolOf({ currency: "jpy", amount: 900 }), "¥900");
+```
+
+### Widen the return type
+
+When the handlers return different types, reach for the widening `W` variant: the
+matcher's return is their union rather than one common type — here
+`string | string[] | undefined`:
+
+```ts
+import { getPrimitiveUnionMatcherW } from "tiny-pattern-ts";
+
+type Field = "name" | "tags" | "note";
+
+const parse = getPrimitiveUnionMatcherW<Field>()({
+    name: () => "Ada",
+    tags: () => ["admin", "beta"],
+    note: () => undefined,
+});
+
+assert.equal(parse("name"), "Ada");
+assert.deepEqual(parse("tags"), ["admin", "beta"]);
+assert.equal(parse("note"), undefined);
+```
+
 ## API
 
 The package exports four factories. Two axes pick one:
@@ -38,7 +172,7 @@ The package exports four factories. Two axes pick one:
 | `getTaggedUnionMatcherW<T>()`    | the value is a discriminated object and handlers return different types   | union of the handlers |
 
 Bind the function that takes the handler map to a `match…` variable once and
-reuse it; the examples below do this, so the builder is allocated once.
+reuse it; the [Examples](#examples) do this, so the builder is allocated once.
 
 ### Primitive-union matchers
 
@@ -152,6 +286,43 @@ provable exhaustiveness — to automate what a `switch` and a default arm alread
 cover. The type-level cost of supporting open universes is recorded in
 [development/library.md](./development/library.md#supported-universes).
 
+## Alternatives
+
+### [`ts-pattern`](https://github.com/gvergnaud/ts-pattern)
+
+- is the full structural matcher — nested and partial patterns, guards, unions,
+  captures — exhausting at `.exhaustive()`
+- has a fluent `.with(…)` chain that is heavy on syntax; tiny-pattern-ts is one
+  handler map
+- is about 2 kB minified and gzipped; tiny-pattern-ts is 0.2 kB
+- reach for it when you need a feature tiny-pattern-ts does not cover
+
+### [Effect's `Match`](https://effect.website/docs/code-style/pattern-matching/)
+
+- is the same piped matcher (`Match.type` / `Match.when` / `Match.exhaustive`),
+  but only as part of the `effect` ecosystem
+- tiny-pattern-ts is standalone: no runtime dependency to buy into
+
+### [`match-iz`](https://github.com/shuckster/match-iz)
+
+- expresses patterns in the TC39 proposal's style, deciding each case at runtime
+- is written in JavaScript with hand-maintained declarations, so its types do
+  not prove the cases exhaustive
+- tiny-pattern-ts does: exhaustiveness is a compile-time guarantee, not an
+  `otherwise` fallback
+
+### plain `switch` (baseline)
+
+- is the zero-dependency baseline — pair it with
+  [`eslint-plugin-strict-pattern-matching`](https://www.npmjs.com/package/eslint-plugin-strict-pattern-matching)
+  for exhaustiveness
+- is a statement, not an expression, so it cannot produce a value directly
+- leaves the `never` guard to you; tiny-pattern-ts is an expression and does not
+  need one
+
+The [TC39 pattern-matching proposal](https://github.com/tc39/proposal-pattern-matching)
+is still stage 1, so userland libraries remain the only option today.
+
 ## License
 
 MIT © 2026 tmu. See [LICENSE](./LICENSE).

backlog.tasks

@@ -7,32 +7,8 @@ Backlog and tracking for tiny-pattern-ts. Managed in vscode-todotasks format.
 Setup:
 ☐ Split off template into separate package => pi --session 01a07dde-7050-7054-bb36-1606d7eb2bc3 @low
 
-v1.0:
-✔ API surface is stable and fully typed @done
-    ✔ Finalize public exports in `src/index.ts` @done
-    ✔ Document all exported types and functions @done
-    ✔ Add JSDoc for public APIs @done
-✔ Test coverage meets threshold @done
-    ✔ Achieve 100% branch coverage on `src/primitive-union.ts` @done
-    ✔ Achieve 100% branch coverage on `src/index.ts` @done
-
-Matcher:
-✔ when using a union type as a property, the current behavior of tagged union matcher is @done
-    to pass never to handler parameters
-    → new matcher function needed or can be fixed in tagged union matcher
-    ✔ optional discriminant (`{ type?: "x" }`) is the same hole: the boolean/nullish change now admits the `undefined` tag, so the factory accepts the key, but `Extract<T, Record<K, V>>` still passes `never` to both the `x` and `undefined` handlers @done
-
 Documentation:
-☐ Bring README.md back to its previous form — synopsis and examples restored, in the correct place
-    → previous section order: title, tagline, Synopsis, Description, Requirements, Examples, API, License, Contributing
-    → previous Examples order: literal/exhaustive, typeof, structural/discriminated unions, when, any
 ☐ Create `examples/` directory with runnable snippets
-☐ Add comparison section vs. other TS pattern-matching libs in Readme.md
-    ☐ Why do we do this? => exhaustiveness encoded type safe
-    ☐ Why this form? little syntax, data last, very small, autocomplete, strict typing in the handler; for more features use ts-pattern
-☐ Write migration guide for users coming from discriminated unions
-☐ Create backlog tasks for implementation
-✔ Validate code fences in Markdown (start with README.md) — compile the TypeScript examples against `src/` so the docs cannot drift from the API @done
 
 Maintenance:
 ☐ Serve CI coverage over a tiny self-hosted webserver (replace the zip artifact) @low

cspell.json

@@ -45,7 +45,8 @@
         "todotasks",
         "connor",
         "injective",
-        "injectivity"
+        "injectivity",
+        "userland"
     ],
     "ignorePaths": ["dist", "node_modules", "coverage", "*.svg", ".gitignore"]
 }

development/tooling.md

@@ -196,27 +196,28 @@ joining the oxfmt-superseded rules already off.
   are part of the public API.
 - The narrower scope keeps the signal high without config-file boilerplate.
 
-### `knip` lists `src/index.ts` as an entry
+### `knip` does not list the library entry
 
 #### Decision (2026-09)
 
-`knip.json` declares `"entry": ["src/index.ts", "scripts/*.ts"]`.
+`knip.json` declares `"entry": ["scripts/*.ts"]`; the library entry
+`src/index.ts` is not listed.
 
 #### Why
 
-- Supplying `entry` **replaces** knip's default entry detection, which otherwise
-  derives the public entry from `package.json` `exports`. Adding `scripts/*.ts`
-  there therefore dropped the library entry, so knip resolved the package through
-  its `dist/index.js` output and reported the unreferenced source entry file
-  `src/index.ts` as an unused file.
-- Naming the source entry restores the link between the public API and the
-  source graph without pointing knip at build output.
+- knip derives the public entry from `package.json` `exports` and resolves it to
+  `src/index.ts` itself, so naming the file is a redundant pattern and
+  `maintain:knip` reports it as a configuration hint.
+- Listing `scripts/*.ts` does not switch that derivation off: the scope stays
+  clean with or without `dist/`, and with the barrel's own test removed.
 
 #### Rejected
 
+- `"src/index.ts"` in `entry`: it silenced an `unused files` report for the
+  barrel, which the derivation above no longer produces; keeping it only adds a
+  hint.
 - `paths` mapping `dist/index.*` back to `src/index.ts`: more config to model a
-  relation the explicit entry states directly, and it would break whenever the
-  build layout changes.
+  relation knip already resolves.
 
 ### `maintain:outdated` ignores `@types/node`
 
@@ -327,7 +328,7 @@ of a hand-rolled JSON-RPC client.
 
 #### Decision (2026-09)
 
-`@spences10/pi-lsp` is pinned to `0.0.46` and used read-only.
+`@spences10/pi-lsp` is pinned to `0.0.47` and used read-only.
 
 #### Why
 

knip.json

@@ -1,5 +1,5 @@
 {
     "$schema": "./node_modules/knip/schema.json",
-    "entry": ["src/index.ts", "scripts/*.ts"],
+    "entry": ["scripts/*.ts"],
     "ignoreDependencies": ["@runwisp/pubv"]
 }

package.json

@@ -1,7 +1,7 @@
 {
     "name": "tiny-pattern-ts",
-    "version": "0.8.1",
-    "description": "Pattern matching for TypeScript/ESM environments (F#-style, not regex)",
+    "version": "0.8.3",
+    "description": "Exhaustive, type-safe pattern matching for TypeScript",
     "keywords": [
         "adt",
         "algebraic-data-types",
@@ -88,7 +88,7 @@
         "knip": "^6.34.0",
         "lefthook": "^2.1.12",
         "mdast-util-from-markdown": "^2.0.3",
-        "oxfmt": "^0.70.0",
+        "oxfmt": "^0.71.0",
         "oxlint": "^1.83.0",
         "oxlint-tsgolint": "^7.0.2001",
         "publint": "^0.3.24",