Tish

Tish is a TypeScript- and JavaScript-compatible language implemented in Rust. It is aimed at teams who want a familiar surface syntax, predictable semantics, and the option to ship either interpreted scripts or runtime free native binaries.

The same source can run on a tree-walking interpreter, a bytecode VM, or compiled targets (native, WASM/WASI, and others). Network, filesystem, and process APIs are feature-gated so defaults stay safe. For the full syntax and semantics, see the canonical spec in-repo; for tutorials and reference, see tishlang.com/docs.

🔥 Features

• JS-like surface — let / const, fn, arrows, template literals, async/await, modules, and a large slice of familiar builtins (console, Math, JSON, arrays, strings, objects).
• Two ways to run — interpret for fast iteration (tish run, REPL); compile to native or WASM for distribution and performance (tish build).
• Memory-safe implementation — Rust-hosted runtime and compiler pipeline; no GC in the host language for the toolchain itself.
• Secure by default — I/O and platform APIs (http, fs, process, etc.) are opt-in via features.
• No undefined — null only where JS would use undefined; strict equality (=== / !==) without loose coercion.
• Optional types — TypeScript-style annotations are parsed for tooling and future checking; see the language reference for status.

Full specification: docs/LANGUAGE.md. Implementation status, gaps, and JS compatibility: docs/plan-gap-analysis.md.

📚 Documentation

User-facing guides and reference:

Section	Description
Getting started	Install Tish, build your first app
First app	Run and build workflows, targets
Editor & IDE	VS Code, LSP, tasks, Neovim
Language server	tish-lsp capabilities
Formatting	tish-fmt
Linting	tish-lint
Interactive REPL	Multi-line input, completion, history
Language overview	Syntax, keywords, semantics
Tish vs JavaScript	Differences and additions from JS
Builtins	Console, Math, JSON, Array, String, Object
Features (APIs)	http, fs, process, regex — feature-gated
Native backend	Rust, Cranelift, LLVM compilation
WASM targets	Web and WASI
Deploy	Platform and hosting

In-repo docs

Contributor- and spec-oriented material in docs/:

File	Purpose
LANGUAGE.md	Canonical language reference (syntax, semantics, builtins)
ecma-alignment.md	ECMA-262 / test262 mapping
plan-gap-analysis.md	Implementation audit, MVP checklist
architecture-next-steps.md	Crate layout, design decisions
builtins-gap-analysis.md	Builtins across Rust vs bytecode VM (Cranelift/WASI)

🛠️ Toolchain

Tool	Purpose
tish	CLI — run, repl, build, dump-ast
tish-fmt	Formatter
tish-lint	Linter (--format sarif for code scanning)
tish-lsp	Language server; uses tish_fmt / tish_lint as libraries
tish-security/ (sibling repo)	Rules & CI examples — clone next to tish/ as ../tish-security (OpenGrep, ast-grep, Comby, Codacy scaffold, fixtures)
tree-sitter-tish/	Tree-sitter grammar (editors, ast-grep, future OpenGrep integration)
VS Code extension	tish-vscode — grammar, snippets, LSP client, tasks

Related docs on tishlang.com: Editor & IDE, Language server, Formatting, Linting.

📦 Installation

Install globally:

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

Or locally with npm:

npm install @tishlang/tish

More options: Installation.

⚡ Quick start

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

▶️ Run and build

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

tish run hello.tish
# Hello, World!

tish build hello.tish -o hello
./hello
# Hello, World!

Native binaries are standalone (no Tish or Rust runtime required on the machine that runs them). Backends, flags, and WASM are covered in First app, Native backend, and WASM targets.

🤝 Contribution

Contributions are welcome. See CONTRIBUTING.md for building, testing, and code style. Tish is licensed under the Pay It Forward License (PIF).

💪 Performance

JavaScript equivalents live in tests/core/*.js. Compare Tish with Node.js or Bun:

./scripts/run_performance_manual.sh

Details: docs/perf.md.

📝 License

Tish is licensed under the Pay It Forward License (PIF). See LICENSE.