lobster VS dafny

I think lobster does this.

"Compile time reference counting / lifetime analysis / borrow checker."[1]

"Reference Counting with cycle detection at exit, 95% of reference count ops removed at compile time thanks to lifetime analysis."[1]

[1] https://strlen.com/lobster/

There is another language, Lobster, that uses lifetime analysis like Rust, but IIUC infers lifetimes completely automatically. It looks like the idea is still experimental - I'm interested to see how it goes.

I think the ability to open a window and do graphical stuff is actually pretty underrated in core language functionality. There's a few game-oriented programming languages like Lobster that put windowing and graphics in the core language functionality, and I think it's pretty neat. The biggest downside is that it's a lot to bite off, because you'll probably want to have standardized API functionality for a whole host of things like font rendering, image loading, etc.

The actual game itself, yes. Based on this open source project though which provides the language its written in and core engine tech: https://github.com/aardappel/lobster

I'm keeping an eye on Lobster though. It fixes most of Python's problems. It's way faster, has proper static typing, the import system is sane, etc.

Lobster (https://strlen.com/lobster/) appears to at least do lifetime analysis to reduce refcounting. I'm not sure about automatic interior mutability. I feel like there's a keyword here that can help find other compilers with similar features.

Also, can I introduce you to https://strlen.com/lobster/, a garbage collected language made for game development by (and primarily for) the one and only Wouter "aardappel" van Oortmerssen?

I would like to make it work to some degree like Rust with a borrow checker, and have optional static typing (with type inference wherever it can). Other sources of inspiration, lobster lang, and dart. It is going to (eventually...) compile to several places like dart (browser, iOS, android, linux, etc.). After I've created the AST, I've gone straight to code generation, because that's the easy part IME. But now have to insert the "middle" and do typechecking/borrowchecking/inference/other checking. This is for an imperative-style language.

Over the ~12 years of Lobster (https://strlen.com/lobster/) 's existence, features that were removed (in this order): * Lexical scoping. * Icon style backtracking. * Small-talk like syntax. * Dynamic Typing. * Multimethods. * Frame based state (like FRP). * Co-routines.

Code correctness is a lost art. I requirement to think in abstractions is what scares a lot of devs to avoid it. The higher abstraction language (formal specs) focus on a dedicated language to describe code, whereas lower abstractions (code contracts) basically replace validation logic with a better model.

C# once had Code Contracts[1]; a simple yet powerful way to make formal specifications. The contracts was checked at compile time using the Z3 SMT solver[2]. It was unfortunately deprecated after a few years[3] and once removed from the .NET Runtime it was declared dead.

The closest thing C# now have is probably Dafny[4] while the C# dev guys still try to figure out how to implement it directly in the language[5].

[1] https://www.microsoft.com/en-us/research/project/code-contra...

[2] https://github.com/Z3Prover/z3

[3] https://github.com/microsoft/CodeContracts

[4] https://github.com/dafny-lang/dafny

[5] https://github.com/dotnet/csharplang/issues/105

I don't think something that specific exists. There are a very large number of formal methods tools, each with different specialties / domains.

For verification with proof assistants, [Software Foundations](https://softwarefoundations.cis.upenn.edu/) and [Concrete Semantics](http://concrete-semantics.org/) are both solid.

For verification via model checking, you can check out [Learn TLA+](https://learntla.com/), and the more theoretical [Specifying Systems](https://lamport.azurewebsites.net/tla/book-02-08-08.pdf).

For more theory, check out [Formal Reasoning About Programs](http://adam.chlipala.net/frap/).

And for general projects look at [F*](https://www.fstar-lang.org/) and [Dafny](https://dafny.org/).

Dafny and Whiley are two examples with explicit verification support. Idris and other dependently typed languages should all be rich enough to express the required predicate but might not necessarily be able to accept a reasonable implementation as proof. Isabelle, Lean, Coq, and other theorem provers definitely can express the capability but aren't going to churn out much in the way of executable programs; they're more useful to guide an implementation in a more practical functional language but then the proof is separated from the implementation, and you could also use tools like TLA+.

https://dafny.org/

https://whiley.org/

https://www.idris-lang.org/

https://isabelle.in.tum.de/

https://leanprover.github.io/

https://coq.inria.fr/

http://lamport.azurewebsites.net/tla/tla.html

> I think we can assume it won't be as efficient has hand written code

Actually, surprisingly, not necessarily the case!

If you'll refer to the discussion in https://github.com/dafny-lang/dafny/issues/601 and in https://github.com/dafny-lang/dafny/issues/547, Dafny can statically prove that certain compiler branches are not possible and will never be taken (such as out-of-bounds on index access, logical assumptions about whether a value is greater than or less than some other value, etc). This lets you code in the assumptions (__assume in C++ or unreachable_unchecked() under rust) that will allow the compiler to optimize the codegen using this information.

Most of the proof assistants out there: Lean, Coq, Dafny, Isabelle, F*, Idris 2, and Agda. And the main concepts are dependent types, Homotopy Type Theory AKA HoTT, and Category Theory. Warning: HoTT and Category Theory are really dense, you're going to really need to research them.

I'm not sure if the author is here, or if my comment attempt was successful. So, can I suggest you take a look at a third leg of the formal methods stool?

If you are familiar with C, check out Frama-C (https://frama-c.com/) and the WP and RTE plugins. The approach is based on Tony Hoare and EWD's axiomatic semantics (https://en.wikipedia.org/wiki/Hoare_logic). It does not have a good memory management story, as far as I know, but is very good for demonstrating value correctness (RTE automatically generates assertions for numeric runtime errors, for example) and many memory errors.

If you are familiar with Ada, check out SPARK (https://www.adacore.com/about-spark), which is similar to Frama-C but has a much better interface in the AdaCore GNAT toolkit and IDE.

Both work similarly: Assertions in normal Ada or C code as well as the code itself are translated into SMT statements and fed to a SMT solver to find counterexamples---errors.

I have some blog posts from several years ago about Frama-C:https://maniagnosis.crsr.net/tags/applied%20formal%20logic.h... (And I really should get back into it; it's a lot of fun.)

If you are not familiar with Ada or C, Dafny (https://dafny.org/) is another option based on .NET and devoleped at Microsoft. It seems nigh-on perfect for this approach. (The language uses a garbage collector.) At the time I was looking, there was little documentation on Dafny, but that seems to have improved.