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Smashing Swift

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Re: Smashing Swift

#61

Post by coldtea »

danabramov wrote: post #37
dirtyaura wrote: post #6

I've had very similar experience: I try to port non-trivial, but still rather simple functional code, for example containing a couple of nested closures, and the compiler crashes. And it seems that the Xcode playground, the command line compiler and REPL all behave a bit differently. In one case playground works, but REPL crashes, in another, compiler works, REPL has trouble of figuring out types. I have absolutely n…

Microsoft's work on C# compiler (Roslyn) is amazing: they offer compiler-as-a-library so the IDE, plugins and debugger use the same backend as the compiler itself. I wish at some point Apple could adopt a similar approach.

Hmm, Apple went there before Roslyn with Clang/LLVM (whose creator is the designer of Swift and works for Apple).

The idea behind LLVM was to have the various compiler stages and tooling be re-usable and plugin like, unlike the monolithic design GCC had.

And Apple already uses the came "compiler-as-a-library" approach, even for Objective-C, to implement: the compiler, the syntax highlight, AST-based auto-completion, debugging and error fix suggestions and other stuff.

I'm pretty sure that the case with Swift is the same. It's just that it's not stable yet, so you can get crashes at various stages of all those pipelines.

Re: Smashing Swift

#62

Post by anko »

danabramov wrote: post #37
dirtyaura wrote: post #6

I've had very similar experience: I try to port non-trivial, but still rather simple functional code, for example containing a couple of nested closures, and the compiler crashes. And it seems that the Xcode playground, the command line compiler and REPL all behave a bit differently. In one case playground works, but REPL crashes, in another, compiler works, REPL has trouble of figuring out types. I have absolutely n…

Microsoft's work on C# compiler (Roslyn) is amazing: they offer compiler-as-a-library so the IDE, plugins and debugger use the same backend as the compiler itself. I wish at some point Apple could adopt a similar approach.

Check out LLVM (http://llvm.org)

Re: Smashing Swift

#63

Post by _random_ »

acqq wrote: post #52
_random_ wrote: post #48

Earlier quoted context omitted.

Just to be clear: innovative for Apple development community or innovative generally? Please list some/all innovations, I would be happy to reconsider.

Apple GUI development is obviously a major constraint. Another is: no GC in order to avoid the collections happening when they want and thus making the smoothness of the UI impossible. I still claim there isn't at this moment any more innovative language that can provide that what Swift provides, observing any GUI platform you want to observe: meaning that level of support for the platform's native GUI with that perf…

I see the source of your confusion now. To me innovation means something absolutely new, not re-applying/combining prior art. Wikipedia agrees: "Innovation differs from improvement in that innovation refers to the notion of doing something different rather than doing the same thing better."

Re: Smashing Swift

#64

Post by Alphasite_ »

danabramov wrote: post #37
dirtyaura wrote: post #6

I've had very similar experience: I try to port non-trivial, but still rather simple functional code, for example containing a couple of nested closures, and the compiler crashes. And it seems that the Xcode playground, the command line compiler and REPL all behave a bit differently. In one case playground works, but REPL crashes, in another, compiler works, REPL has trouble of figuring out types. I have absolutely n…

Microsoft's work on C# compiler (Roslyn) is amazing: they offer compiler-as-a-library so the IDE, plugins and debugger use the same backend as the compiler itself. I wish at some point Apple could adopt a similar approach.

I'm pretty sure thats what they've always done, at least for the time they've used LLVM.

Re: Smashing Swift

#65

Post by acqq »

_random_ wrote: post #63
acqq wrote: post #52

Earlier quoted context omitted.

Apple GUI development is obviously a major constraint. Another is: no GC in order to avoid the collections happening when they want and thus making the smoothness of the UI impossible. I still claim there isn't at this moment any more innovative language that can provide that what Swift provides, observing any GUI platform you want to observe: meaning that level of support for the platform's native GUI with that perf…

I see the source of your confusion now. To me innovation means something absolutely new, not re-applying/combining prior art. Wikipedia agrees: "Innovation differs from improvement in that innovation refers to the notion of doing something different rather than doing the same thing better."

Apple is doing something different and new, comparing all available languages capable to produce fast non-stuttering GUI based applications that work smoothly even on the smartphones and demand minimal resources. And it's not a small feat by any comparison.

It's like you'd read about the first usable jet-powered car and then claim "but it's not innovative, there were jet powered planes already."

Re: Smashing Swift

#66

Post by freyrs3 »

dscrd wrote: post #26
wting wrote: post #17

Earlier quoted context omitted.

A functor is a thing that can be mapped over. For example: map abs [-1, 2, 3] => [1, 2, 3] Arrays are the simplest example, but it looks like an iterable. However functors retain shape whereas iterables don't. For example if we had a tree (represented visually): oak = -1 / \ 2 3 If we used oak as an iterable, we would lose the structure of the tree: map abs iter(oak) => [1, 2, 3] However if tree belongs to the functo…

>However functors retain shape whereas iterables don't. Wow. Such a simple sentence yet this is the first time I have read it, and it makes the concept much more clear than hundreds of articles before did. Thank you! I wish all FP features would be explained so simply.

Though if you take this intuition too far it tends to break down, for instance IO and ST both define functor instances but it doesn't really make sense to talk about a functor over IO preserving shape.

Re: Smashing Swift

#67

Post by coldtea »

_random_ wrote: post #42
acqq wrote: post #30

Still, I look at the Swift with a low-level colored glasses: I don't care if this or that category theory aspect is covered or not. I don't care if you can imagine some nicer syntax for something (everybody can). I really care how good and how often Swift can be used instead of C, not being slower and not using more resources. I know, is nicer. But for me, if it has GC, it's a no go. I see Swift as something where I…

The language is not "innovative" as they claim, so people are expecting at least some learning from mistakes of prior languages. They could've hired some smart people from more software-oriented companies or something.

>The language is not "innovative" as they claim

Not innovative compared to what? Haskell? Unfinished betas like Rust? Some language 100 people use (plus 1-2 banks and a couple of universities)?

This is a language that will jump in the top ten of most used languages in a year or so, just because it's used in a hugely popular development platform. And it had to fulfil several things to achieve that.

>They could've hired some smart people from more software-oriented companies or something

Because Chris Lattner, the guy behind the infrastructure of tens of new languages and one of the most popular C/C++ compilers, is not smart enough right? Or the team that created Swift.

And which company would that be? Go, for one, is like a 1980 language compared to Swift. And C# had 14 years to evolve, and didn't have the same functionality constrains Swift has handicapped with at all.

Re: Smashing Swift

#68

Post by jkrems »

twic wrote: post #49
jkrems wrote: post #27

Earlier quoted context omitted.

Well, derived classes are meant to be drop-in replacement for the base class. In that sense it totally makes sense that you can't have a non-generic child class of a generic base class. Otherwise it encourages design where classes are treated as method dumps.

No. If the child class binds the type parameter of the base class (as in this example), then it's meaningless to think of that class as being generic. In this example, Bar is always Bar - you can't have a Bar or a Bar . So why not just call it Bar? FWIW, this is how it works in Java, and it seems to work. Indeed, calling it Bar seems really weird to me. Usually, in a declaration, the thing inside the angle brackets i…

I don't think Java is a good example for OOP best practice. For exactly these reasons. I can't think of a reason this should be allowed. It screams "I'm trying to misuse class hierarchy to do specialization instead of using composition".

Re: Smashing Swift

#69

Post by platz »

jmah wrote: post #38

I successfully got the Functor example to work like this: protocol Functor { typealias T typealias FunctorResult func map (mappingFunction: T -> P) -> FunctorResult } extension Dictionary : Functor { func map (mappingFunction: ValueType -> P) -> Dictionary { var newDict:Dictionary = [:] for (key, value) in self { newDict[key] = mappingFunction(value) } return newDict } }

Some folks are working on a library for this already: https://github.com/maxpow4h/swiftz

Re: Smashing Swift

#70

Post by ScottBurson »

leorocky wrote: post #8

I don't understand what a functor is or why an array is a functor. Can anyone please explain? I did the wikipedia article for category theory and I read some stack overflow questions and I'm not sure I understand why an array is a functor. It seems some languages have their own meaning for what a "functor" is, confusing the issue. My initial guess is that a functor is just sort of like a function that casts or does s…

The term "functor" is badly overloaded in general -- almost every language that uses the term has its own definition. In C++, it's an object that can be called as a function (by virtue of defining 'operator()') [0]. In Prolog, it's the head and arity of a term [1]. In ML, it's a function from structures to structures [2].

[0] http://www.stanford.edu/class/cs106l/course-reader/Ch13_Func...

[1] http://www.swi-prolog.org/pldoc/man?predicate=functor/3

[2] http://en.wikipedia.org/wiki/Standard_ML#Module_system

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