Clarity, compiled.

A readable language that compiles to native code and WebAssembly.

shapes.lcd

choice Shape
    Circle(radius: float)
    Square(side: float)
    Point

task area(self: Shape) -> float
    return match self
        Circle(radius) -> 3.14159 * radius * radius
        Square(side) -> side * side

print Square(side: 3.0).area()

$ lucid check shapes.lcd
shapes.lcd:9:9: error E0316: this `match` does not cover every `Shape`
  note: add an arm for `Point`

choice Shape
    Circle(radius: float)
    Square(side: float)
    Point

task area(self: Shape) -> float
    return match self
        Circle(radius) -> 3.14159 * radius * radius
        Square(side) -> side * side

print Square(side: 3.0).area()

$ lucid check --json shapes.lcd
[{"code":"E0316","severity":"error","message":"this `match` does not cover every `Shape`","file":"shapes.lcd","line":9,"column":9,"end_line":9,"end_column":21,"notes":["add an arm for `Point`"],"fixes":[]}]

choice Shape
    Circle(radius: float)
    Square(side: float)
    Point

task area(self: Shape) -> float
    return match self
        Circle(radius) -> 3.14159 * radius * radius
        Square(side) -> side * side
        Point -> 0.0

print Square(side: 3.0).area()

$ lucid run shapes.lcd
9.0

Explicit where it matters.

Signatures say what changes, what fails, and what runs on another thread. The compiler infers the rest.

What it does	What you write
Readable by default	`task is_adult(self: User) -> bool`
Inferred ownership, value semantics	`var b = a`
Memory safety without a garbage collector	`if index is not none`
Native code through Cranelift	`lucid build hello.lcd`
WebAssembly for the browser	`lucid build --target web hello.lcd`
Explicit errors, mutation, and concurrency	`bump(change total, 3)`
Diagnostics and tools for agents	`lucid check --json main.lcd`

All features, with examples and limits

Eight milestones done. The ecosystem is next.

2/9

M8 steps done. M8 adds Linux, a package registry, SQLite, cryptography, a language server, and the 1.0 stability promise.

Read the roadmap

M0DesignDone
M1Hello worldDone
M2Core languageDone
M3DataDone
M4Ownership performanceDone
M5A usable languageDone
M6BrowserDone
M7Concurrency and serversDone
M8EcosystemIn progress
M9Self-hosted front endPlanned

A handful of commands.

Every command also speaks JSON with --json. Binaries are not published yet, and the source repository is not public.

Command	What it does
`lucid run hello.lcd`	Compiles with a JIT and runs it.
`lucid check hello.lcd`	Reports errors, and prints nothing when there are none.
`lucid test hello.lcd`	Runs the file’s tests.
`lucid build hello.lcd`	Writes a standalone executable.
`lucid build --target web hello.lcd`	Writes one .js file for a browser or Node.
`lucid explain E0316`	Explains a diagnostic code.

What a build from source needs