Doo: A Simple, Fast Programming Language Built on Rust and LLVM
Hey HN!
https://github.com/nynrathod/doolang
I'm Nayan, and I'm stoked to share Doo, my project turned side hustle for a lang that's dead simple to write but punches like Rust. Think clean syntax (inspired by Rust but less boilerplate), auto memory mgmt via ref counting (no GC pauses), rich types, and it spits out standalone native bins via LLVM/clang.
Why Doo? Coding should feel fun, not fighty. No more wrestling with lifetimes or macros just to get a "hello world" but still safe and speedy.
Quick tour (hello.doo):
fn main() { let msg = "Hey HN!"; print(msg); }
Static Type System: Compile-time type checking with type inference Automatic Memory Management: Reference counting for data types Rich Data Types: Integers, strings, booleans, arrays, maps, and tuples Module System: Organize code with a hierarchical import system Control Flow: Conditional statements, for loops, and range iteration Function System: First-class functions with parameter and return type annotations Native Compilation: Compiles to standalone executables using clang/lld
Repo: https://github.com/nynrathod/doolang (stars/pulls welcome!)
What do you think? Too Rust-y? Missing a killer feature?
The idea and syntax looks good for me. I like it's clean an minimalistic design. But still it's to early to say is it good or not. Because there is no obvious features. You should answer the question what's the goal of the language and find the auditory who is right for you.
Did you write it or generate? If the later, then it's could be even more impressive in some way.
I think there is a bit of a additional value here. It's very good as a learning project, like "how to make you own programming language and compile it into executable". Due to the simplicity and minimalism, it could be very useful.
Hi,
Yeah make sense, but I don't have any buzzing goal right now, doolang is not any dsl, just to ensure high level syntax for developer writing backend servers apis. And not started as learning project. Will move forward as per feedback of community and requirement but not such specific target im aiming. so again simple concept is keep it simple to write with speed and security
Is it safe?
Does it require using traits everywhere, like Rust does?
Does it have proper references (C++ style)?
Saying safe will be too early, but design philosophy is no compromise with security and speed with easy syntax. It passed with 550+ test cases including unit test, memory stress, integration, circular dep, regresssion, valgrind memory leak, fuzz testing, also i added conservative limits max depth for recursion and data length for stability. Find here https://github.com/nynrathod/doolang/blob/main/src/limits.rs
Doolang not uses any traits like rust. Rust is great language, but its expose everything in syntax that is also great but as developer who want security+speed with fast development may found issue writing rust, that is main goal of doolang simlicity. I'm still figuring out further design principle of syntax to have less exposing syntax.
Doolang have auto memory management with reference counting. Just simple mut keyword introduced for mutating variable let mut data = "data"; no other syntax expose all handling automatic with rc and auto type define if not defined explicitly
Nooooo! "valgrind memory leak". Aaargh. Valgrind (memcheck) is not just a leak detection tool. Leak detection is so unimportant that it isn't even turned on by default.
Thanks for pointing that out. I didn’t actually know all the details about how Valgrind works under the hood just that it does memory checking. I'll definitely read up more on it. If you have any good resources or tips, I'd appreciate your suggestions!
When I say safety I mean inability of the programmer to trigger UB using normal language features, like it's impossible in Rust and several other (less known) languages. Does Doo support it? Or I just can shoot the leg and compiler lets me do this?
About references: am I correct, that any value is reference-counted and one can pass it to a function and mutate it (the original, not a copy).
Doolang aims for memory safety with static typing and automatic reference counting, so you won't see classic C/C++ bugs. But it does not claim Rust's level of safety there’s no formal guarantee that safe code can't cause undefined behavior. It's quite safe in practice, just not as strict as Rust.
For complex types (strings, arrays, maps), values are reference-counted and passed by reference. If you pass such a value to a function, you're sharing the same object—mutations affect the original. For primitives (Int, Bool), it's pass-by-value (copy).
So, what if I want to pass a value of a primitive type by-reference? How the equivalent code for the following C++ example looks like?
Doolang currently does not allow you to mutate a primitive variable from another function.
Only support this as of now
fn Foo(x: Int) { x = 123; // Only modifies Foo's local copy print("inside Foo", x); // Print 123 } fn main() { let x: Int = 0; Foo(x); // x is still 0 here after Foo returns print("out x", x); // Print 0 }
But your points make sense, i should learn those UB works and will check how its behaving
what are the kind of things you are building yourself with this?
Hi,
So main goal of this language is to have simplicity while writing code. Rust is great will dominate, but as dev who want speed and security but with high level syntax, doolang is best for them. Right now im working on std library and inbuilt function, and moving forward I will integrate doolang with my own note taking app uoozer note https://play.google.com/store/apps/details?id=com.uoozer.not... , 550+ test cases covered by doolang already with valgrind memroy test too.
so for roadmap, after inbuilt functions and standard library deployment will build http router and will test real world scenario for api dev. IF all well then will integrate with uoozer note.