Rip

A modern language that compiles to JavaScript

Rip is a modern language inspired by CoffeeScript. It compiles to ES2022 (classes, ?., ??, modules), adds about a dozen new operators, includes built-in reactivity, and sports a self-hosting compiler with zero dependencies — all in about 10,800 lines of code.

No imports. No hooks. No dependency arrays. Just write code.

data = fetchUsers!                  # Dammit operator (call + await)
user = User.new name: "Alice"       # Ruby-style constructor
squares = (x * x for x in [1..10])  # List comprehension

str =~ /Hello, (\w+)/               # Regex match
log "Found: #{_[1]}"                # Captures in _[1], _[2], etc.

get '/users/:id' ->                 # RESTful API endpoint, comma-less
  name = read 'name', 'string!'     # Required string
  age  = read 'age' , [0, 105]      # Simple numeric validation

What makes Rip different:

• Modern output — ES2022 with native classes, ?., ??, modules
• New operators — !, !?, //, %%, =~, |>, .new(), and more
• Reactive operators — :=, ~=, ~> as language syntax
• Optional types — :: annotations, ::= aliases, .d.ts emission
• Zero dependencies — everything included, even the parser generator
• Self-hosting — bun run parser rebuilds the compiler from source

Installation

bun add -g rip-lang            # Install globally

rip                            # Interactive REPL
rip file.rip                   # Run a file
rip -c file.rip                # Compile to JavaScript

Language

Functions & Classes

def greet(name)                # Named function
  "Hello, #{name}!"

add = (a, b) -> a + b          # Arrow function
handler = (e) => @process e    # Fat arrow (preserves this)

class Dog extends Animal
  speak: -> log "#{@name} barks"

dog = Dog.new("Buddy")         # Ruby-style constructor

String Interpolation

"Hello, #{name}!"              # CoffeeScript-style
"Hello, ${name}!"              # JavaScript-style
"#{a} + #{b} = #{a + b}"       # Expressions work in both

Both #{} and ${} compile to JavaScript template literals. Use whichever you prefer.

Destructuring & Comprehensions

{name, age} = person
[first, ...rest] = items

squares = (x * x for x in [1..10])   # Array comprehension
console.log x for x in items         # Loop (no array)

Async & Chaining

def loadUser(id)
  response = await fetch "/api/#{id}"
  await response.json()

user?.profile?.name            # Optional chaining
data = fetchData!              # Await shorthand

Iteration

for item in [1, 2, 3]         # Array iteration (for-in)
  console.log item

for key, value of object       # Object iteration (for-of)
  console.log "#{key}: #{value}"

for x as iterable              # ES6 for-of on any iterable
  console.log x

for x as! asyncIterable        # Async iteration shorthand
  console.log x                # Equivalent to: for await x as asyncIterable

loop                           # Infinite loop (while true)
  process!
loop 5                         # Repeat N times
  console.log "hi"

Implicit it

Arrow functions with no params that reference it auto-inject it as the parameter:

users.filter -> it.active          # → users.filter(function(it) { ... })
names = users.map -> it.name       # no need to name a throwaway variable
orders.filter -> it.total > 100    # works with any expression

Reactivity

State, computed values, and effects as language operators:

Types (Optional)

Type annotations are erased at compile time — zero runtime cost:

def greet(name:: string):: string        # Typed function
  "Hello, #{name}!"

User ::= type                            # Structural type
  id: number
  name: string

enum HttpCode                            # Runtime enum
  ok = 200
  notFound = 404

Compiles to .js (types erased) + .d.ts (types preserved) — full IDE support via TypeScript Language Server. See docs/RIP-TYPES.md.

Operators

Heredoc & Heregex

Heredoc — The closing ''' or """ position defines the left margin. All content is dedented relative to the column where the closing delimiter sits:

html = '''
    <div>
      <p>Hello</p>
    </div>
    '''
# Closing ''' at column 4 (same as content) — no leading whitespace
# Result: "<div>\n  <p>Hello</p>\n</div>"

html = '''
    <div>
      <p>Hello</p>
    </div>
  '''
# Closing ''' at column 2 — 2 spaces of leading whitespace preserved
# Result: "  <div>\n    <p>Hello</p>\n  </div>"

Heregex — Extended regex with comments and whitespace:

pattern = ///
  ^(\d{3})    # area code
  -(\d{4})    # number
///

vs React / Vue / Solid

Rip's reactivity is framework-agnostic — use it with React, Vue, Svelte, or vanilla JS.

Rip UI

Ship the 40KB Rip compiler to the browser. Components are .rip source files, compiled on demand, rendered with fine-grained reactivity. No build step. No bundler.

Counter = component
  @count := 0

  render
    div.counter
      h1 "Count: #{@count}"
      button @click: (-> @count++), "+"
      button @click: (-> @count--), "-"

Two keywords — component and render — are all the language adds. Everything else (:= state, ~= computed, methods, lifecycle) is standard Rip.

See @rip-lang/ui for the full framework: file-based router, reactive stash, component store, and renderer.

vs CoffeeScript

Smaller codebase, modern output, built-in reactivity.

Browser

Run Rip directly in the browser — inline scripts and the console REPL both support await via the ! operator:

<script type="module" src="/rip/browser.js"></script>
<script type="text/rip">
  res = fetch! 'https://api.example.com/data'
  data = res.json!
  console.log data
</script>

The rip() function is available in the browser console:

rip("42 * 10 + 8")                                         // → 428
rip("(x * x for x in [1..5])")                             // → [1, 4, 9, 16, 25]
await rip("res = fetch! 'https://api.example.com/todos/1'; res.json!")  // → {id: 1, ...}

Try it live: shreeve.github.io/rip-lang

Architecture

Source  ->  Lexer  ->  emitTypes  ->  Parser  ->  S-Expressions  ->  Codegen  ->  JavaScript
           (1,958)    (types.js)     (359)       ["=", "x", 42]     (3,378)      + source map

Simple arrays (with .loc) instead of AST node classes. The compiler is self-hosting — bun run parser rebuilds from source.

The Rip Stack

Rip includes optional packages for full-stack development:

bun add -g @rip-lang/db    # Installs everything (rip-lang + api + db)

Implicit Commas

Rip rescues what would be invalid syntax and gives it elegant meaning. When a literal value is followed directly by an arrow function, Rip inserts the comma for you:

# Clean route handlers (no comma needed!)
get '/users' -> User.all!
get '/users/:id' -> User.find params.id
post '/users' -> User.create body

# Works with all literal types
handle 404 -> { error: 'Not found' }
match /^\/api/ -> { version: 'v1' }
check true -> enable()

This works because '/users' -> was previously a syntax error — there's no valid interpretation. Rip detects this pattern and transforms it into '/users', ->, giving dead syntax a beautiful new life.

Supported literals: strings, numbers, regex, booleans, null, undefined, arrays, objects

Quick Reference

rip                    # REPL
rip file.rip           # Run
rip -c file.rip        # Compile
rip -t file.rip        # Tokens
rip -s file.rip        # S-expressions
bun run test           # 1225 tests
bun run parser         # Rebuild parser
bun run browser        # Build browser bundle

Documentation

Zero Dependencies

{ "dependencies": {} }

Everything included: compiler, parser generator, REPL, browser bundle, test framework.

Philosophy

Simplicity scales.

Simple IR (S-expressions), clear pipeline (lex -> parse -> generate), minimal code, comprehensive tests.

Inspired by: CoffeeScript, Lisp, Ruby | Powered by: Bun

MIT License

Start simple. Build incrementally. Ship elegantly.