Building Hew

Explore the design of Hew, from actor isolation and supervision to native compilation and developer tools.

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Launching Hew

Hew puts actor state, supervision, protocol shape, and cleanup into the compiler instead of scattering them across conventions.

May 10, 2026 · 5 min read

Playground Status Examples Comparisons Getting started FAQ

Oct 21, 2026 · 5 min read

Hew 0.6.2: safer values, steadier services

Edit parsed configuration without changing its source value, then see how Hew 0.6.2 carries the same actor reference across local and remote services.

Oct 16, 2026 · 5 min read

Hew 0.6.1: typed configuration and confined services

Check deployment settings at build time, reuse generic closures and give an actor access to one directory.

Oct 16, 2026 · 28 min read

language release

A tour of Hew 0.6: files, concurrent work and services

Start with a small file tool, then follow the language features that let it grow into a service with owned resources, workers and typed protocols.

Hew Notes

Language development, engineering articles, releases and community projects. About once a month, with an extra issue for a significant release. Written in English.

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Topics

Case Study (4) Compiler (33) Design (18) Distributed (1) Infrastructure (5) Language (1) Language Design (7) Launch (1) Release (20) Runtime (7) Stdlib (2) Tooling (7)

Series

Building Hew

16 parts

Hew started with a 394-line specification, a 1,076-line gap analysis, and four research documents — before any compiler code existed.

MicroGPT

3 parts

I needed a real program to stress-test the compiler. A 120-line GPT turned into 1,092 lines of Hew, and a third of those lines were working around compiler bugs.

daily-progress

11 parts

First day of the v0.5 rewrite. I tore out the `<-` send operator and the spawn-lambda form, and spent the rest of the day deciding what the actor and machine surface should look like before a single line of it lowers to a binary.

deep-dive

7 parts

The backend cutover for v0.5 — the borrowed-String double-free that took six revisions to kill, why each revision grew the C++ walker registry, and how I convinced myself it was safe to delete a 1,568-file MLIR subtree and lower straight from MIR to LLVM IR.

All Posts

October 2026

Oct 21 Hew 0.6.2: safer values, steadier services release 5 min read Oct 16 Hew 0.6.1: typed configuration and confined services release 5 min read Oct 16 A tour of Hew 0.6: files, concurrent work and services language release 28 min read Oct 14 Hew 0.6.0: concurrent work with ordinary calls release 4 min read

June 2026

Jun 2 Closing the Gaps: std Imports Compile Native, HashMap Indexing, and Idiomatic Examples compiler stdlib 8 min read

May 2026

May 30 Two ways to be generic: monomorphisation, and the day abstract types lowered without one compiler design 11 min read May 30 Abstract type parameters with value witnesses, and a receive ABI that can borrow compiler design 7 min read May 29 No GC, no double-free: ownership, copy-on-write strings, and fail-loud traps compiler design 11 min read May 28 String Becomes Copy-on-Write and the Last Legacy Dispatch Path Is Retired compiler design 8 min read May 26 Collections get a real ABI, closures get capture inference, and dispatch goes through one authority compiler design 9 min read May 24 Hardening the Seams Instead of Adding Surface compiler design 8 min read May 23 Talking between nodes: the CBOR wire envelope and a SWIM cluster that gossips compiler design 11 min read May 22 Generators get a state machine, the cluster learns to gossip, and the wire format flips to CBOR compiler runtime 8 min read May 22 State as a type: how machine declarations become tagged-union dispatch compiler design 11 min read May 21 Generic Enums End-to-End and the Day for and while Finally Lower compiler 7 min read May 20 State Machines Reach Codegen and Closures Become First-Class Values compiler design 7 min read May 19 Supervisors That Wire Themselves and Crash Hooks With Real Trap Codes compiler design 7 min read May 19 Sends are method calls, crashes carry codes: the actor and supervision model compiler design 11 min read May 19 WASM parity for free, almost: four targets from one MIR and the seams that weren't free compiler design 10 min read May 18 From Parse Tree to Running Actor compiler 8 min read May 17 Retiring the C++ Backend and Teaching the Compiler to Monomorphise compiler design 8 min read May 17 Decide in MIR, carry in nothing: why we deleted the MLIR backend before shipping a binary compiler design 9 min read May 16 Making integers honest and making failure loud: widths, records, and trap-on-overflow compiler design 8 min read May 15 Deleting the Send Operator to Make the Actor Model Honest design compiler 7 min read May 10 Launching Hew launch design 5 min read May 7 The Double-Free and the Sized Integers compiler design 6 min read May 1 Releasing v0.4.0 — LSP goto-definition, stdlib fixes, and WASM coverage release 5 min read

April 2026

Apr 29 The JIT REPL Can Survive a Crash Now tooling compiler 5 min read Apr 26 Comments Are Not Optional tooling compiler 6 min read Apr 18 Hardening the Standard Library's Error Paths compiler stdlib 7 min read Apr 10 Making the Compiler Fail Closed compiler 6 min read Apr 6 Releasing v0.3.0 — Structural Bounds, In-Process REPL, and Stdlib Depth release 7 min read

March 2026

Mar 29 Releasing v0.2.2 — Observer Discovery, Reply Channel Fix, WebSocket Server release 5 min read Mar 23 Releasing v0.2.1 — One Binary, Hardened Runtime release 4 min read Mar 16 Wiring the QUIC Mesh infrastructure distributed 8 min read Mar 12 Releasing v0.2.0 — Named Receivers and Generic impl Blocks release 3 min read Mar 12 Teaching an LLM a Language It Has Never Seen tooling case-study 10 min read Mar 10 MicroGPT — From 1,092 Lines to 677 case-study 5 min read Mar 9 What MicroGPT Found — 13 Bugs and 340 Lines of Workarounds case-study compiler 6 min read Mar 8 Porting Karpathy's MicroGPT to Hew case-study 7 min read Mar 7 Releasing v0.1.9 — FreeBSD Support release 2 min read Mar 7 Wire Types and Distributed Actors runtime 11 min read Mar 6 Releasing v0.1.8 — Literal Coercion, Indirect Enums, and LLVM 22 release 2 min read Mar 5 LSP, Tree-Sitter, and Editor Support tooling 7 min read Mar 4 Releasing v0.1.7 — Debugging and Collection Ergonomics release 2 min read Mar 3 Releasing v0.1.6 — State Machines, Wire System, and a Lot of Cleanup release 2 min read Mar 3 State Machines and Duration Literals language-design runtime 6 min read Mar 2 The Package Manager and Ecosystem Libraries tooling 7 min read Mar 1 Building the Website and the Playground infrastructure 5 min read

February 2026

Feb 27 Releasing v0.1.5 — Static Linking and Benchmarks release 2 min read Feb 27 Type System Improvements After the Initial Release compiler 5 min read Feb 26 Releasing v0.1.4 — False Warnings, Over-Engineering, and Windows release 2 min read Feb 25 Releasing v0.1.3 — Packaging and Signing Fixes release 2 min read Feb 25 Releasing v0.1.2 — Build System Fixes release 2 min read Feb 25 Tagging v0.1.0 and Building the Release Pipeline release infrastructure 5 min read Feb 24 Releasing v0.1.1 — Codegen Fixes and FFI Linking release 2 min read Feb 23 Releasing v0.1.0 — Initial Public Release release 2 min read Feb 21 Fixing Generics and Adding Verification compiler 6 min read Feb 20 Pre-Alpha Syntax Cleanup language-design 7 min read Feb 19 Running Valgrind on Everything runtime 6 min read Feb 19 Closing the Gaps compiler runtime 5 min read Feb 19 Replacing FlatBuffers with MessagePack compiler tooling 6 min read Feb 17 Grammar Tooling and the MLIR Dialect Overhaul tooling infrastructure 4 min read Feb 15 Testing the Language on Myself language-design compiler 5 min read Feb 15 Generators and Actor Mailboxes language-design runtime 6 min read Feb 15 Removing Six Syntax Redundancies language-design 5 min read Feb 15 How Fast Is It, Actually infrastructure 3 min read Feb 14 Throwing Away the First Compiler compiler 6 min read Feb 14 Three Spec Revisions in Three Days language-design 5 min read Feb 13 Building the Actor Runtime runtime 7 min read Feb 12 From cargo init to a Running Compiler compiler 6 min read Feb 12 Writing a Spec Before Writing Code language-design 5 min read