Singular

One owner. One way. No surprises.

Singular is a compiled, memory-safe programming language. It's designed to run as fast as C, to be as safe as Rust, and to be much easier to read and learn than either.

Read the examples llms.txt for AI models

What it looks like

struct Item {
    String name
    Float price
}

fn discount(edit List[Item] items, Float percent) {
    for Item item in edit items {
        item.price *= 1.0 - percent / 100.0
    }
}

fn main() {
    List[Item] cart = [Item { name: "book", price: 20.0 }]
    discount(edit cart, 10.0)
    print("{cart[0].name}: {cart[0].price:.2}")
}

Every name is declared with its type. discount may change the cart, so the call says edit cart.

The idea in one paragraph

Every value has one owner. A function can view what you pass it, which is the default, edit it, or move it (take it for good). edit and move are written at the call site too, so f(x) never changes x, f(edit x) might, and after f(move x) the variable x is gone. You can tell what happens to every variable from the line it's on, and every name is declared with its type, so you can always tell what it is.

Views can't be stored or returned. That means all safety checking happens inside one function at a time, so there are no lifetime annotations, no garbage collector, and no hidden copies.

Design choices at a glance

SingularInstead of
Int score = 0, with const in front for names that never changelet/var and types you have to guess
No pointers: * only ever means multiply*p, &x, **, ->
edit and move written at the call site, with view as the defaultLifetimes, &, &mut, Box, Rc<RefCell<T>>
Arena[T] + Handle[T] for linked dataReference-counted pointer graphs
raises E, try and catchExceptions you can't see, or Result plus a "fallible" twin of every helper
comptime values, [comptime Int N] parameters and comptime ifMacros and build scripts
Braces, no semicolons, one formatterSignificant indentation or style debates
and, or, not, any Trait&&, ||, !, dyn Trait
Types UpperCamelCase, values lower_snake_case (enforced)Guessing what a name refers to
Stable error codes with fixes, and JSON output for tools and AI agentsError text you have to scrape

Status

Singular is a v0.1 draft. The design is written down, and the compiler is being built in stages.