Comment by josephg

> And types are often not the best way to achieve static safety.

That’s a sort of weird statement to make without reference to any particular programming language. Types are an amazing way to achieve static safety.

The question of how much safety you can reasonably achieve using types varies wildly between languages. C’s types are pretty useless for lots of reasons - like the fact that all C pointers are nullable. But moving from C to C++ to Rust to Haskell to ADA gives you ever more compile time expressivity. That type expressivity directly translates into reduced bug density. I’ve been writing rust for years, and I’m still blown away by how often my code works correctly the first time I run it. Yesterday the typescript compiler (technically esbuild) caught an infinite loop in my code at compile time. Wow!

I’d agree that every language has a sweet spot. Most languages let you do backflips in your code to get a little more control at compile time at the expense of readability. For example, C has an endless list of obscure __compiler_directives that do all sorts of things. Rust has types like NonZeroUsize - which seem like a good idea until you try it out. It’s a good idea, but the ergonomics are horrible.

But types can - and will - take you incredibly far. Structs are a large part of what separates C from assembler. And types are what separates rust from C. Like sum types. Just amazing.