I agree with Ted that I would have expected the inner members of a class to be 
private by default. (Not a big deal if I have to explicitly prefix most of my 
concerned vars now - but it is just different to what I would have expected). 
Certainly, in the past, I would be more used to having to explicitly define 
chosen vars as “public” ( e.g. in the past world of Objective C I  was used to 
defining selected vars with @synthesize to “open them up" )

On 13 Oct 2016, at 22:27, Ted F.A. van Gaalen via swift-evolution 
<swift-evolution@swift.org<mailto:swift-evolution@swift.org>> wrote:

Please do NOT drop the current distinction between *private* and *fileprivate*
as it is now in Swift 3
It is needed for correct OOP.

As written before, but now a bit more compact, I hope:

I would like to have the inner members of a class as default private,
(not fileprivate)  that is, that each entity inside the class body is not 
in the outer scope. not even in the same file!

I would only reveal entities of a class to the outer scope that are 
(as is the case with class properties in Objective-C and most other OOP 
supporting languages)

This is what I have to do now,
Each and every entity that I wish to keep hidden
I have to prefix with *private*: like in this example class:
This is tedious and should be unnecessary.

class TG3DGauge: SCNNode

    private var needles = [SCNNode]()
    private var fmtStr = “" // private should be the default!

    var value: CGFloat = 0  // access default “internal”! Visible to the 
outside world.
        didSet  // trigger value change, rotate needles etc.

    private var nodeUnitText = SCNNode()
    private var nodeValueText = SCNNode()

    private var valRange: ClosedRange<CGFloat> = (0...100.0)
    private var valScaleFactor: CGFloat = 1

// etc. much more stuff here and
        // most of it should be private, that is
        // only visible within the class body!
} // end class TG3DGauge

If I don’t specify an access modifier, then the default
for the items defined in classes is *internal*,
which means that these items are visible in the whole application source.

However, this is only desirable for items that I want to
reveal explicitly, of course.
That is exactly why I need the *private* access modifier as it is now
and not *fileprivate*
So I am very glad that this access modifier *private* finally became
available in Swift 3

In my classes, *private* is probably the most used keyword, but
*private* should be the default for entities within a class body
just like it is for entities within functions.

As far as I know, prefixing with *private* is the only solution in Swift to 
functions, vars etc. in my class against unwanted access
from the outer scope. I think this is not the way it should be.

Making all entities in a class private prevents this.
and offers also reasonable protection against
the Fragile Base Class problem, (thanks Chris for url) :

A solution for as it is now, albeit not a perfect one would be,
to have some sort of access modifier which defines
all items within the class to be private by default.
perhaps the keyword *closedscope* like in this example:

closedscope class TG3DGauge: SCNNode

    var needles = [SCNNode]()  // is now private by default
    var fmtStr = “"            // is now private by default

    public var value: CGFloat = 0 // Public!! visible outside class
                               // “fileprivate" or “internal”  can also be used.
        didSet  // trigger value change, rotate needles etc.

    var nodeUnitText = SCNNode()  // is now private by default
    var nodeValueText = SCNNode() // is now private by default


Again, for this reasons, don’t drop the distinction between
between *fileprivate* and *private*
if this is done, there is afaics no way to protect items within a class body.
Leave it as it is now, please. (also to prevent source breaking as well)

(btw, the above TG3DGauge class is a perfect example:
With real gauges it would not be a good idea if one can touch
the needles and gears inside the gauge’s casing,
which is exactly the case with OOP. e.g.
In my class example people would e.g. be able to set the angle
from needles (if not declared private)  directly, without updating the value.)

www.tedvg.com<http://www.tedvg.com/>  (see my gauges from above class here)

Le 13 oct. 2016 à 07:52, Chris Lattner via swift-evolution 
<swift-evolution@swift.org<mailto:swift-evolution@swift.org>> a écrit :

On Oct 12, 2016, at 9:56 PM, Russ Bishop via swift-evolution 
<mailto:swift-evolution@swift.org>> wrote:
I actually consider it very lucky that most of our changes so far have been 
fairly non-controversial. Everybody has a different idea of what would make 
Swift a better language, and all of us well-meaning. But when those ideas 
conflict, some group is going to end up unhappy. I'm actually very glad that 
(a) we haven't had too many of these cases, and (b) even when we have, people 
have been able to accept it and move on to contributing to the next issue.

Strong agreement here as well. This proposal has been litigated numerous times 
already, and the bar for source-breaking changes is much higher now. To 
effectively re-open the discussion would require a proposal that significant 
changes the model with a lot of evidence that such a new model is a drastic 
improvement over what we have now. “Back out SE-0025” is not a viable option 

- Doug

Not really. This proposal could be backed out without source-breaking changes 
by treating private as a synonym for fileprivate and we’d have Swift 2 behavior 
without breaking source. If the core team doesn’t want to consider that then we 
can just move on and live with it.

Not speaking for the core team, just MHO:

I agree with Russ here, and with others who have said upthread that the “thing 
that has changed” is that we are starting to get usage experience with 
fileprivate vs private.  I think we all understand the value of having fewer 
access control levels, and so if “private” isn’t conceptually pulling its 
weight, then it is reasonable to consider phasing it out.

That said, there is no specific rush to have this discussion, and I think it is 
reasonable to put a pretty high burden of proof on someone who wants to drive 
such a proposal.  For example, if we had the discussion in the spring 
timeframe, we should have a pretty large body of Swift 3 code readily at hand 
(e.g. SwiftPM packages and other various github repos).

Given that, it should be easy enough to see how widely private is actually 
being used in practice.  If it is very rare, then the argument to ditch it 
(make it a synonym for fileprivate, and eventually phasing out fileprivate) is 
strong.  If lots of people are using private and only some are using 
fileprivate, then the discussion is quite different.


I don’t think monitoring the usage of private vs fileprivate is fair. By 
default, people will use private until they encounter visibility issues and 
discover they need to change to fileprivate. So private will probably being use 
far more than fileprivate.
Nonetheless it does not mean people chosen private because it effectively 
reduce the visibility to the class scope, but just because it is easier to 
discover and to type than fileprivate and fit in many cases.

I tend to write class will all ivars private by default (as it is a sensible 
default), and then, when I start to write extensions and other parts, I have to 
switch to fileprivate for a bunch of ivars. It create an inconsistent mess in 
my ivars declaration as it is difficult to know if an ivar is private because I 
has to be, or because I didn’t encounter a case that need it to be fileprivate 

Honestly, I don’t see any value in the introduction of fileprivate.
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