Malte UblandClaude Opus 5.5 4c2adcf123 Convert a union of tuples into an array slot
A value typed as a union of tuples or arrays, such as the `as const`
key-table read `SEQUENCES[functionKey]` in pi, was refused with SC2003
when it flowed into a `string[]` or `readonly string[]` slot. A single
tuple already converted through the width family's tuple-to-array
rebuild; a union of tuples had no plan at all.

widthLiftPlan gains the unionArr step for an array destination: every
non-unit arm must lift on its own tag (a tuple rebuilds through
tupleArr, an array copies or lifts through arr), and a unit arm takes
the stranded TypeError, since the slot has no representation for it.
%union.arr dispatches on the runtime tag and applies each arm's lift;
applyWidthLift and one coerceToExpected hook wire it into the top-level
edges that the nested slots already reach through the plan.

The step is planned only after the union-into-one-of-its-arms rule and
only when no arm of the source is already the destination, so every
union that converted before - `T[] | undefined` into `T[]`, optional
array fields, `??=` - keeps byte-identical IR; only sources with no
conversion at all gain one.

Adds the differential corpus program, its cost file, an IR unit test,
and the order-parity baseline.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-27 16:44:46 -07:00
2026-10-16 10:33:14 -05:00
2026-10-14 17:27:02 -05:00
2026-10-25 11:26:13 -05:00
2026-07-22 18:08:04 -05:00
2026-10-25 21:21:26 -05:00
2026-07-22 18:08:04 -05:00

scriptc

Vercel Labs Experiment npm version: scriptc License: Apache-2.0 npm downloads per month: scriptc

scriptc compiles TypeScript and JavaScript to native executables and WebAssembly. It uses the types checked by the TypeScript compiler to generate machine code, and the output runs without Node.js installed. npm packages your program imports compile along with it. Code scriptc can't compile is reported at build time with a diagnostic and, where available, a rewrite hint.

scriptc is experimental and supports a subset of JavaScript, TypeScript, and Node.js APIs. Run scriptc coverage on an existing program to see how much of it compiles, and see the limitations and Node.js compatibility reference for details.

Installation

Install with Node.js 24 or later and npm:

$ npm install -g scriptc

The installed compiler runs natively on macOS, Linux, and Windows. Node.js is needed only to install it and to run WASI modules with scriptc run. Standalone compiler archives are also available from GitHub Releases.

Building executables requires a linker and the platform SDK or sysroot. See the quickstart for prerequisites and platform support for host requirements, cross-compilation, and WebAssembly.

Build a program

Create hello.ts:

const who = process.argv.length > 2 ? process.argv[2] : "world";
console.log(`hello, ${who}`);

scriptc run compiles the file and runs the result:

$ scriptc run hello.ts
hello, world

scriptc build writes an executable:

$ scriptc build hello.ts -o hello >/dev/null
$ ./hello scriptc
hello, scriptc

These examples use POSIX shell syntax. On Windows, build hello.exe and run it with .\hello.exe.

Use scriptc coverage hello.ts to check what compiles before you build. See coverage reports for details.

Use Node APIs

Supported Node APIs compile to the native runtime. For example, server.ts:

import { createServer } from "node:http";

const server = createServer((req, res) => {
  res.setHeader("content-type", "application/json");
  res.end(JSON.stringify({ path: req.url }));
});

server.listen(8080, () => {
  console.log("listening on http://localhost:8080");
});
$ scriptc build server.ts -o server >/dev/null
$ ./server
listening on http://localhost:8080

Use npm packages

npm packages compile into the executable with your code, so it doesn't read node_modules at runtime.

Create cli.ts:

import pc from "picocolors";

console.log(pc.green("hello from scriptc"));
$ npm install picocolors
$ scriptc build cli.ts -o cli >/dev/null
$ ./cli
hello from scriptc

Package support is partial. See npm dependencies for which packages compile and how to check them.

Documentation

Contributing

See CONTRIBUTING.md for source setup, testing, native artifact builds, and docs development.

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Readme Apache-2.0
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