Tish

🚧 Experimental

A highly experimental and opinionated javascript/typescript-like multi-target native compilable language built for friends and family of the JS community.

See docs/ for spec and ECMA alignment; user-facing docs: tishlang.com/docs.

Quick Example

// hello.tish
let name = "World"
console.log(`Hello, ${name}!`)

fn add(a, b) = a + b
console.log(`1 + 2 = ${add(1, 2)}`)

Two Ways to Execute Tish Programs

Tish supports two execution modes: interpret or compile to native.

1. RUN (Interpreter)

Execute .tish files directly without a build step:

tish run hello.tish
# Hello, World!
# 1 + 2 = 3

Best for: development, scripting, quick iteration.

2. BUILD (Compile to Native)

Compile .tish files to standalone native executables:

tish compile hello.tish -o hello
./hello
# Hello, World!
# 1 + 2 = 3

Best for: distribution, performance, deploying without Tish installed. To deploy apps to the Zectre Platform, see the Deploy guide in the documentation.

The compiled binary is fully standalone — no Tish or Rust runtime needed to run it.

Native backend options

Backend	Flag	Use when
rust	--native-backend rust (default)	Full Rust ecosystem; supports native imports (tish:*, @scope/pkg)
cranelift	--native-backend cranelift	Pure Tish only; faster build, no cargo; errors if native imports present

tish compile hello.tish -o hello                    # default: rust backend
tish compile hello.tish -o hello --native-backend cranelift   # cranelift (pure Tish only)

WebAssembly (browser)

Compile to real .wasm for the browser:

tish compile hello.tish -o app --target wasm
# Produces: app_bg.wasm, app.js, app.html

Requirements: rustup target add wasm32-unknown-unknown, cargo install wasm-bindgen-cli

Open app.html via a local server (CORS): python3 -m http.server then visit the URL.

For JavaScript transpilation (no WASM), use --target js instead.

WebAssembly (Wasmtime/WASI)

Compile to a single .wasm for Wasmtime or any WASI runtime:

tish compile hello.tish -o app --target wasi
wasmtime app.wasm
# Hello, World!

Requirements: rustup target add wasm32-wasip1, install Wasmtime

Installing Tish

Homebrew (macOS & Linux)

brew tap tishlang/tish https://github.com/tishlang/tish
brew install tish

Via npx (no install)

npx @tishlang/tish run hello.tish
npx @tishlang/tish compile hello.tish -o hello

Or create a new project:

npx @tishlang/create-tish-app my-app
cd my-app && npx @tishlang/tish run src/main.tish

From source

cargo build --release -p tish

The binary is target/release/tish. Add it to your PATH or run directly.

Note: Compiling to native (tish compile) requires rustc and must be run from the workspace root (needs access to crates/tish_runtime).

Developer tooling

Editor tooling is separate from the compiler (tish = run / repl / compile / dump-ast only).

Tool	Purpose
tish	Run, REPL, compile, dump-ast — the language implementation.
tish-fmt	Formatter (cargo build --release -p tish_fmt → tish-fmt).
tish-lint	Linter (cargo build --release -p tish_lint → tish-lint).
tish-lsp	Language server — links tish_fmt / tish_lint as libraries for editor integration.
VS Code extension	tish-vscode — grammar, snippets, LSP client, tasks.

User-facing docs: Editor & IDE, Language server, Formatting, Linting. Contributor notes: docs/tooling.md.

Using just (Recommended)

The project includes a justfile for common tasks:

# Run a tish file (interpreter, all features)
just run run hello.tish

# Compile to native binary
just compile hello.tish hello
./hello

# Compile to WebAssembly (Wasmtime)
just compile-wasi hello.tish hello
wasmtime hello.wasm

# Run in secure mode (no network/fs/process access)
just run-secure run hello.tish

See just --list for all available recipes.

Feature Flags

Tish has compile-time feature flags for security:

Flag	Enables
http	Network access (fetch, fetchAll, serve) — Fetch-style Promises + ReadableStream
fs	File system (readFile, writeFile, mkdir, etc.)
process	Process control (process.exit, process.env, etc.)
regex	Regular expressions (RegExp, String.match, etc.)
full	All features

Default: no features (secure mode). Use --features full for development.

Log levels: Control output with TISH_LOG_LEVEL=debug|info|log|warn|error

Test

cargo test -p tish

Tests:

• test_full_stack_parse – lex + parse each .tish file
• test_mvp_programs_interpreter – run via interpreter
• test_mvp_programs_native – compile to native, run, compare stdout to static expected (*.tish.expected)

Run any test file: tish run tests/core/<name>.tish

Releasing

→ How to release (step-by-step)

Releases are GitHub-led and do not modify main. The main CI does not push to main; it creates a release branch and a GitHub prerelease.

1. On push to main (with conventional commits that trigger a release): CI runs semantic-release in dry-run to get the next version, creates/updates a branch release/vX.Y.Z, and creates a prerelease on GitHub via the API (with the platform zip attached). There is no version bump or tag on main.
2. When you’re ready: In GitHub, open the prerelease, attach any extra artifacts if needed, then use Set as latest release (uncheck “Set as a pre-release”). That promotes the prerelease to a full release.
3. Publish workflows (run when a full release is published or edited to no longer be a prerelease):
   • NPM: Publishes @tishlang/tish and @tishlang/create-tish-app to npm.
   • Crates.io: Publishes all tishlang_* crates to crates.io.
   • Homebrew: Updates Formula/tish.rb in this repo (tap = this repo).

This gives time for the pipeline (or you) to attach the right binaries; publishing only occurs when the release is promoted.

Required secrets

Secret	Used by	Purpose
NPM_TOKEN	NPM release	Publish to npm
CARGO_REGISTRY_TOKEN	Crates.io release	Publish crates
No extra secrets for Homebrew — it pushes Formula/tish.rb to this repo using GITHUB_TOKEN.

Conventional commits

Use these commit message formats so semantic-release can determine the next version:

Type	Example	Release impact
feat:	feat: add optional chaining	Minor (1.0.0 → 1.1.0)
fix:	fix: correct loop bound	Patch (1.0.0 → 1.0.1)
perf:	perf: faster parser	Patch (1.0.0 → 1.0.1)
docs:	docs: update README	No release by default
chore:	chore: bump deps	No release by default
Breaking	feat!: change API or body BREAKING CHANGE:	Major (1.0.0 → 2.0.0)

Format: <type>(<scope>): <description>, e.g. fix(vm): handle empty array.

Performance Comparison

JavaScript equivalents in tests/core/*.js. Compare Tish vs Node.js/Bun:

./scripts/run_performance_manual.sh

Features

• Variables: let (mutable), const (immutable)
• Functions: fn name(a, b) { ... } or fn name(a) = expr
• Async/await: await fetch / await fetchAll (native); interpreter: --backend interp for top-level await
• Arrow functions: x => x * 2, (a, b) => a + b
• Template literals: `Hello, ${name}!`
• Control flow: if/else, while, for, for..of, switch
• Operators: +, -, *, /, %, **, ===, !==, &&, ||, ??, ?.
• Data: Arrays [], Objects {}, with mutation support
• Built-ins: console.log, Math.*, JSON.*, Object.keys/values/entries
• Array methods: map, filter, reduce, find, forEach, push, pop, etc.
• String methods: slice, split, trim, toUpperCase, includes, etc.

See docs/plan-gap-analysis.md for full feature list and JS compatibility.