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I think the convergence here is toward 'automatically discoverable types'. For python et al this means type annotation (because it's extremely difficult for dis

by morei 6y ago

I think the convergence here is toward 'automatically discoverable types'. For python et al this means type annotation (because it's extremely difficult for discover types otherwise). For C++ et al this is things like the 'auto' keyword that allow skipping the type specification where the compiler can work it out. The end-game is specifying just enough type information that it's still understandable to both humans and compilers.

throwaway189262 6y ago
Typescript is extremely good at this. Rust is pretty good. Even Java is okay now. I firmly believe type inference is the future. Most objects in dynamic languages are statically typed anyways, the type just isn't exposed at compile time.
- hhas01 6y ago
  Type inference is good, but it’s not a full answer. For instance, how often do you declare a variable as `int`, when what you really want to say is “an integer in the range 0...100”? A few languages (e.g. Eiffel) provide a formal mechanism for declaring these sorts of constraints, but most don’t, and you end up putting what should be declarative type-level information into the body of your code instead. And then there’s “cutting-edge” stuff like dependent types, where you really want to express one argument’s type in terms of another argument’s, a classic example being an array indexing method, where you really want to declare the index at compile time as an integer in the range `0..<array.length`, and let the type system propagate that rule and its implications throughout the code that uses it. Whereas most “modern” languages chuck a run-time error if you’re lucky; or just ralph and dump stack like some antiquated 1970s throwback (yeah, looking at you, Apple’s Swift). 3/10 Could do much better.
- smichel17 6y ago
  Huh. I generally enjoy Typescript, but have been frustrated by its inference at times, particularly with regard to generics -- there are places where it will do fine if you pass an arrow function directly, but if you pull it out into a const, the compiler will no longer be able to infer types (and thus fails to compile if you have noImplicitAny enabled).
  - throwaway189262 6y ago
    I've found it's inference to be great, but the error messages GCC-like

by morei 6y ago

throwaway189262 6y ago

Typescript is extremely good at this. Rust is pretty good. Even Java is okay now. I firmly believe type inference is the future. Most objects in dynamic languages are statically typed anyways, the type just isn't exposed at compile time.

hhas01 6y ago
Type inference is good, but it’s not a full answer. For instance, how often do you declare a variable as `int`, when what you really want to say is “an integer in the range 0...100”? A few languages (e.g. Eiffel) provide a formal mechanism for declaring these sorts of constraints, but most don’t, and you end up putting what should be declarative type-level information into the body of your code instead. And then there’s “cutting-edge” stuff like dependent types, where you really want to express one argument’s type in terms of another argument’s, a classic example being an array indexing method, where you really want to declare the index at compile time as an integer in the range `0..<array.length`, and let the type system propagate that rule and its implications throughout the code that uses it. Whereas most “modern” languages chuck a run-time error if you’re lucky; or just ralph and dump stack like some antiquated 1970s throwback (yeah, looking at you, Apple’s Swift). 3/10 Could do much better.
smichel17 6y ago
Huh. I generally enjoy Typescript, but have been frustrated by its inference at times, particularly with regard to generics -- there are places where it will do fine if you pass an arrow function directly, but if you pull it out into a const, the compiler will no longer be able to infer types (and thus fails to compile if you have noImplicitAny enabled).
- throwaway189262 6y ago
  I've found it's inference to be great, but the error messages GCC-like