Getting Started

What is Ori?

Ori is a general-purpose, expression-based language with strict static typing, type inference, and mandatory testing. Every function requires tests, every effect is explicit, and the compiler enforces code integrity.

Install

curl -fsSL https://ori-lang.com/install.sh | sh

Your First Program

Create a file called hello.ori:

@main () -> void = print(msg: "Hello, World!")

Run it:

ori run hello.ori

Functions and Testing

Every function in Ori requires tests. Here’s a function with its test:

@add (a: int, b: int) -> int = a + b

@test_add tests @add () -> void = run(
    assert_eq(actual: add(a: 2, b: 3), expected: 5),
    assert_eq(actual: add(a: -1, b: 1), expected: 0),
)

@main () -> void = run(
    print(msg: "2 + 3 = " + str(add(a: 2, b: 3)))
)

Key Concepts

  • Mandatory testing — every function needs @test blocks or the compiler rejects it
  • Named arguments — add(a: 2, b: 3) not add(2, 3)
  • Expression-based — everything is an expression, no statements
  • No null — use Option<T> for optional values, Result<T, E> for errors
  • Explicit effects — functions declare capabilities like uses Http

Try It Online

Head to the Playground to write and run Ori code in your browser.

Next Steps