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> I personally would welcome a new language that gives me full-spectrum dependent types with great tooling and moderate performance. I'd propose to have a look

> I personally would welcome a new language that gives me full-spectrum dependent types with great tooling and moderate performance. I'd propose to have a look at Swift. It is very similar to Rust in many aspects (particularly the type system), with slower performance (due to some of the abstractions). The tooling on macOS is already really good, on Linux it is getting there, and on Windows the next release will add official support.

hhas01 6y ago
Swift is just C++ with rubberized corners. Distinctly “meh” as a language in its own right, embarrassingly knotty around its ObjC bridging (there’s a basic impedance mismatch between those two worlds), and certainly doesn’t have anything as powerful as dependent types.
- h-cobordism 6y ago
  > embarrassingly knotty around its ObjC bridging (there’s a basic impedance mismatch between those two worlds) I think they've done an incredible job with their ObjC interop, given said mismatch. But you're right — the person above who said that > The world has enough cookie cutter procedural and OOP languages. definitely isn't looking for Swift.
  - exdsq 6y ago
    But it doesn’t have dependent types does it?
    - hhas01 6y ago
      Nope. I think it periodically gets floated on Swift-Evolution, but someone would have to design and implement it… and I suspect the Swift codebase (which is C++; it isn’t even self-hosting) is already fearsomely complex as it is. Or, to borrow another Tony Hoare quote: “There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult.” .. Alas, big complex codebases facilitate fiddling with the details over substantive changes; and that’s even before considering if the Swift language’s already-set syntax and semantics are amenable to expressing concepts they weren’t originally designed for. Stuff like Swift evo’s current thrash over trailing block[s] syntax reminds me of Python’s growth problems (e.g. its famously frustrating statement vs expression distinction that’s given rise to all its `lambda…`, `…if…else…`, etc nonsense). It’s hard to scale after you’ve painted yourself into a corner; alas, the temptation is to start digging instead. I really wish Alan Kay had pursued his Nile/Gezira work further. That looked like a really promising approach to scalability. We really need better languages to write our languages in.
  - hhas01 6y ago
    “I think they've done an incredible job with their ObjC interop, given said mismatch.” Which is to say, the Swift devs have done an incredible job of solving the wrong problem. Apple needed a modern language for faster, easier Cocoa development. What they got was one that actually devalues Apple’s 30-year Cocoa investment by treating it as a second-class citizen. Gobsmacking hubris! Swift was a pet project of Lattner’s while he was working on LLVM that got picked up by Apple management and repurposed to do a job it wasn’t designed for. Swift should’ve stayed as Lattner’s pet project, and the team directed to build an “Objective-C 3.0”, with the total freedom to break traditional C compatibility in favor of compile-time safety, type inference, decent error handling, and eliminating C’s various baked-in syntactic and semantic mistakes. Leave C compatibility entirely to ObjC 2.0, and half the usability problems Swift has immediately go away. The result—a modern dynamic language that feels like a scripting language while running like a compiled one, which treats Cocoa as a first-class citizen, not as a strap-on. (Bonus if it also acts as an easy upgrade path for existing C code. “Safe-C” has been tried before with the likes of Cyclone and Fortress, but Apple might’ve actually made it work.) Tony Hoare called NULL a billion-dollar mistake. Swift is easily a 10-million-man-hour mistake and counting. For a company that once prided itself for its perfectly-polished cutting-edge products, #SwiftLang is so very staid and awkward-fitting.
    - cmrdporcupine 6y ago
      I don't have enough experience with Swift to agree or disagree with you about it, but it strikes me that there were already Smalltalk-like languages out there that fit this niche somewhat -- such as F-Script -- and Apple could have gone down that road instead of shoehorning Swift into the role. Objective C already had Smalltalk-style message dispatch syntax, and something fairly close to Smalltalk blocks/lambdas. So it's not like existing Cocoa programmers would have been frustrated or confused. Clearly the original NeXT engineers were inspired by Smalltalk and wanted something like it, but had performance concerns etc, perhaps there would have been performance concerns with moving to a VM based environment for mobile devices, but I think with a modern JIT these problems could be alleviated. As we've seen with V8, etc.. So I think it was actually a missed opportunity for Smalltalk to finally have its day in the sun :-)
cmrdporcupine 6y ago
I don't see how Swift is similar to Rust -- it's a garbage collected, OO language, not really appropriate for low level / systems level programming. It's a nice looking language for what it is, with some nicer modern features in its type system etc, but its niche is not the same as Rust.
- throwaway894345 6y ago
  > it's a garbage collected, OO language, not really appropriate for low level / systems level programming I'm of the impression that Swift is reference counted, which, while technically a kind of GC, is also appropriate for low level / systems programming (which isn't to say that Swift is a good language for low level / systems programming; only that its memory management isn't the disqualifying factor).
  - cmrdporcupine 6y ago
    I wouldn't consider reference counted GC systems level appropriate. It _can_ be more deterministic, but not when it's tracing and collecting cycles (which a decent modern RC implementation must do) and it usually plays havoc on L1 cache (by touching counts). You can make RC quite nice (I've written cycle collecting implementations before) but there's reasons why C++ programmers are encouraged generally to avoid shared_ptr and use unique_ptr whenever possible: harder to reason about or trace object lifetimes, and performance implications. Now if the garbage collection was optional, and one could still freely heap or stack allocate and free, then, yes, I could see it. But I don't think that's the case w/ Swift, at least not last time I looked at it. It's also why Go is imho not a 'systems' programming language.
    - ken 6y ago
      > I wouldn't consider reference counted GC systems level appropriate. It _can_ be more deterministic, but not when it's tracing and collecting cycles (which a decent modern RC implementation must do) Swift has what you would call an ‘indecent’ RC design, then, because it doesn’t. > and it usually plays havoc on L1 cache (by touching counts). Swift (like Objective-C) can store the refcounts either inline or in supplementary structures, for performance. > Now if the garbage collection was optional In the common case, it practically is, as (most) value types will only ever live on the stack, or inline in another data structure.

hhas01 6y ago

Swift is just C++ with rubberized corners. Distinctly “meh” as a language in its own right, embarrassingly knotty around its ObjC bridging (there’s a basic impedance mismatch between those two worlds), and certainly doesn’t have anything as powerful as dependent types.

h-cobordism 6y ago
> embarrassingly knotty around its ObjC bridging (there’s a basic impedance mismatch between those two worlds) I think they've done an incredible job with their ObjC interop, given said mismatch. But you're right — the person above who said that > The world has enough cookie cutter procedural and OOP languages. definitely isn't looking for Swift.
- exdsq 6y ago
  But it doesn’t have dependent types does it?
  - hhas01 6y ago
    Nope. I think it periodically gets floated on Swift-Evolution, but someone would have to design and implement it… and I suspect the Swift codebase (which is C++; it isn’t even self-hosting) is already fearsomely complex as it is. Or, to borrow another Tony Hoare quote: “There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult.” .. Alas, big complex codebases facilitate fiddling with the details over substantive changes; and that’s even before considering if the Swift language’s already-set syntax and semantics are amenable to expressing concepts they weren’t originally designed for. Stuff like Swift evo’s current thrash over trailing block[s] syntax reminds me of Python’s growth problems (e.g. its famously frustrating statement vs expression distinction that’s given rise to all its `lambda…`, `…if…else…`, etc nonsense). It’s hard to scale after you’ve painted yourself into a corner; alas, the temptation is to start digging instead. I really wish Alan Kay had pursued his Nile/Gezira work further. That looked like a really promising approach to scalability. We really need better languages to write our languages in.
- hhas01 6y ago
  “I think they've done an incredible job with their ObjC interop, given said mismatch.” Which is to say, the Swift devs have done an incredible job of solving the wrong problem. Apple needed a modern language for faster, easier Cocoa development. What they got was one that actually devalues Apple’s 30-year Cocoa investment by treating it as a second-class citizen. Gobsmacking hubris! Swift was a pet project of Lattner’s while he was working on LLVM that got picked up by Apple management and repurposed to do a job it wasn’t designed for. Swift should’ve stayed as Lattner’s pet project, and the team directed to build an “Objective-C 3.0”, with the total freedom to break traditional C compatibility in favor of compile-time safety, type inference, decent error handling, and eliminating C’s various baked-in syntactic and semantic mistakes. Leave C compatibility entirely to ObjC 2.0, and half the usability problems Swift has immediately go away. The result—a modern dynamic language that feels like a scripting language while running like a compiled one, which treats Cocoa as a first-class citizen, not as a strap-on. (Bonus if it also acts as an easy upgrade path for existing C code. “Safe-C” has been tried before with the likes of Cyclone and Fortress, but Apple might’ve actually made it work.) Tony Hoare called NULL a billion-dollar mistake. Swift is easily a 10-million-man-hour mistake and counting. For a company that once prided itself for its perfectly-polished cutting-edge products, #SwiftLang is so very staid and awkward-fitting.
  - cmrdporcupine 6y ago
    I don't have enough experience with Swift to agree or disagree with you about it, but it strikes me that there were already Smalltalk-like languages out there that fit this niche somewhat -- such as F-Script -- and Apple could have gone down that road instead of shoehorning Swift into the role. Objective C already had Smalltalk-style message dispatch syntax, and something fairly close to Smalltalk blocks/lambdas. So it's not like existing Cocoa programmers would have been frustrated or confused. Clearly the original NeXT engineers were inspired by Smalltalk and wanted something like it, but had performance concerns etc, perhaps there would have been performance concerns with moving to a VM based environment for mobile devices, but I think with a modern JIT these problems could be alleviated. As we've seen with V8, etc.. So I think it was actually a missed opportunity for Smalltalk to finally have its day in the sun :-)

cmrdporcupine 6y ago

I don't see how Swift is similar to Rust -- it's a garbage collected, OO language, not really appropriate for low level / systems level programming. It's a nice looking language for what it is, with some nicer modern features in its type system etc, but its niche is not the same as Rust.

throwaway894345 6y ago
> it's a garbage collected, OO language, not really appropriate for low level / systems level programming I'm of the impression that Swift is reference counted, which, while technically a kind of GC, is also appropriate for low level / systems programming (which isn't to say that Swift is a good language for low level / systems programming; only that its memory management isn't the disqualifying factor).
- cmrdporcupine 6y ago
  I wouldn't consider reference counted GC systems level appropriate. It _can_ be more deterministic, but not when it's tracing and collecting cycles (which a decent modern RC implementation must do) and it usually plays havoc on L1 cache (by touching counts). You can make RC quite nice (I've written cycle collecting implementations before) but there's reasons why C++ programmers are encouraged generally to avoid shared_ptr and use unique_ptr whenever possible: harder to reason about or trace object lifetimes, and performance implications. Now if the garbage collection was optional, and one could still freely heap or stack allocate and free, then, yes, I could see it. But I don't think that's the case w/ Swift, at least not last time I looked at it. It's also why Go is imho not a 'systems' programming language.
  - ken 6y ago
    > I wouldn't consider reference counted GC systems level appropriate. It _can_ be more deterministic, but not when it's tracing and collecting cycles (which a decent modern RC implementation must do) Swift has what you would call an ‘indecent’ RC design, then, because it doesn’t. > and it usually plays havoc on L1 cache (by touching counts). Swift (like Objective-C) can store the refcounts either inline or in supplementary structures, for performance. > Now if the garbage collection was optional In the common case, it practically is, as (most) value types will only ever live on the stack, or inline in another data structure.