Feather
a fresh Tcl reimplementation (WASM, Go)
Details
- External ID
- 46401944
- Source
- HN
- Company
- —
- Product
- Feather
- Website domain
- feather-lang.dev
- Launched
- Dec. 27, 2025
- Cohort
- —
- Upvotes
- 31
- Upvotes percentile
- 0.7366412213740458
- Tags
- —
- Fetched at
- Sept. 7, 2026, 9:25 p.m.
- Updated at
- Sept. 7, 2026, 9:25 p.m.
Description
Hey HN!First time showing something here, but I've been furiously working over the holidays on Feather, a from scratch reimplementation of TCL designed for embedding in modern applications.It's starting out as a faithful reimplementation of TCL without I/O, OOP features, or coroutines.TCL has a special place in my heart because the syntax is so elegant for interactive use, and defining domain specific languages.My motiviation is twofold: faster feedback loops for AI, and moldable software for users.It turns out giving AI agents access to the runtime state of your program makes for really fast feedback loops, but embedding existing options in a world where shipping binaries for each platform is commonplace is tricky.Embedding the real TCL is tricky because it comes with its own event loop (in 2025 you alreay have one), a GUI framework (you have a web framework already, or develop on mobile), and has access to the filesystem (don't forget to delete all commands with file system access!).Feather just doesn't ship with those - expose only what you need from your application.A WASM build comes out of the box and clocks in at ~120kb plus 70kb for connecting it to the browser or node.js.And if embedding becomes easy, you can put a REPL everywhere: in mobile apps, in desktop software, as a control plane into web servers.I want to imagine a world where all software is scriptable just like Emacs and nvim, with agents doing the actual work.
Enrichment
- Theme
- browser automation and scraping for AI
- Vertical
- Horizontal
- Function
- Dev tools
- Audience
- Developer
- AI stance
- Not AI
- Project type
- Hobby / open-source project
- Normalized one-liner
- tcl reimplementation in wasm and go
- Manually corrected
- False
Could you build this?
No Writing a faithful, embeddable programming language interpreter with WASM compilation from scratch requires deep compiler and interpreter design expertise.
What it would actually take: A developer needs extensive knowledge of interpreter design, lexical analysis, AST generation, and runtime evaluation mechanics in Go, followed by compiling to WebAssembly. Reimplementing Tcl entails faithfully modeling its unique 'everything is a string' execution model, variable scoping rules (upvar/uplevel), and control structures without relying on modern off-the-shelf parser generators.
Discussion
5 comments analyzed.
Competitors mentioned: Jimtcl, Original Tcl
Concerns raised: Name confusion with existing old Feather project, Reference counting complexity
Feature requests: WASM browser support, First-class multithreading support
Competitors
Other products that read as similar to this one — 70 launches clear the similarity bar, closest 8 shown.
Attention rank: #26 of 71 (itself plus its competitors, highest first — normalized so YC and Product Hunt are compared fairly).
Launched 57 days after the earliest competitor.
- Urlx · hn · 2026-03-23 · 5 upvotes · similarity 0.42
- Mach · hn · 2026-06-08 · 32 upvotes · similarity 0.42
- Askfeather.ai · hn · 2026-02-03 · 7 upvotes · similarity 0.38
- Juggler · hn · 2026-07-12 · 280 upvotes · similarity 0.38
- HTML, CSS and JavaScript in the Terminal · hn · 2026-07-13 · 9 upvotes · similarity 0.38
- Browser4 · hn · 2025-12-13 · 7 upvotes · similarity 0.37
- Catsu: A unified Python client for embedding APIs · hn · 2025-12-17 · 7 upvotes · similarity 0.37
- Coi · hn · 2026-01-20 · 225 upvotes · similarity 0.37
Other launches for this product
- No other launches for this product.
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