Readit NewsSound type systems are equivalent to proof systems.
You can use them to design data structures where their mere eventual existence guarantee the coherence and validity of your program’s state.
The basic example is “Fin n” that carries at compile time the proof that you made the necessary bounds checks at runtime or by construction that you never exceeded some bound.
Some languages allow you to build entire type level state machines! (eg. to represent these transactions and transitions)
Even Rust's types aren't going to help you if two arguments simply have the same types.
Or another (dummy) example transfer(accountA, accountB). Make two types that wrap the same type but one being a TargetAccount and the other SourceAccount.
Use the type system to help you, don’t fight it.
I'm pretty sure Rosenblatt was criticized back then for his non-tangible stupid ideas, and why the hell was his research was funded to begin with.
f(x) = 1 if x is rational, 0 otherwise.
It is defined over all real numbers but continuous nowhere. Also if you take the Dirichlet function and multiply it by x so you get
g(x) = x if x is rational, 0 otherwise
…then you have something that is continuous at exactly one place (0) and nowhere else, which also is pretty spectacular.
Decades ago we were calling out these software and now it’s the norm.
Another example along the line: I wanted to extract a frame from a video on iOS, it’s impossible with the built-in tools (screenshot aside) and found that someone built a paid app only for that.
I tell you where we’re heading, we’re screwed.
The blog claims that @pool "solves memory lifetimes with scopes" yet it looks like a classic region/arena allocator that frees everything at the end of a lexical block… a technique that’s been around for decades.
Where do affine or linear guarantees come in?
From the examples I don’t see any restrictions on aliasing or on moving data between pools, so how are use‑after‑free bugs prevented once a pointer escapes its region?
And the line about having "solved memory management" for total functions::: bravo indeed…
Could you show a non‑trivial case where @pool eliminates a leak that an ordinary arena allocator wouldn’t?
Could you show a non‑trivial case, say, a multithreaded game loop where entities span multiple frames, or a high‑throughput server that streams chunked responses, where @pool prevents leaks that a plain arena allocator would not?