[swift-evolution] [swift-evolution-announce] [Review] SE-0159: Fix Private Access Levels

Ricardo Parada rparada at mac.com
Fri Mar 24 08:49:07 CDT 2017

After reading the discussions it seems to me that renaming private -> scoped and fileprivate -> private might keep both sides happy. 

> On Mar 24, 2017, at 9:06 AM, Vladimir.S via swift-evolution <swift-evolution at swift.org> wrote:
>> On 24.03.2017 11:47, Jonathan Hull via swift-evolution wrote:
>> Nevin had a fantastic proposal for submodules which changed private to mean
>> “private to the submodule”, where each file was implicitly a submodule
>> unless you declared otherwise.  Simple and elegant.
> Currently I don't see how submodules can eliminate the needs of 'scoped'(current 'private') access level. Even in submodule (even if submodule will be a "namespace" line feature like "submodule Name{..}" and we can have number of such declarations in the same file) - 'scoped' access is valuable even for single type declaration. Probably I don't understand something.
> But as for fileprivate - it is really logically to have it named 'private' and it can naturally be used in submodules as "private to submodule" just like "private to file" currently.
> So I do think the right move currently is to rename fileprivate->private, private->scoped and then, when(if!) we have submodules - we can change something.
> Rename will remove the huge confusion users(especially novice) have with 'fileprivate' vs 'private'; experience shows that *actually* programmers use 'fileprivate' a lot and this is some kind of Swift/iOs programming style, and fileprivate is awkward keyword, and many(all? ;-)  just want 'private' means "in this file".
> Also novice programmer can know just about 'public', 'internal' and 'private' - these three logically united access modifiers,all are file-scoped, but more experienced programmer has no problems teach what 'scoped' means and why one want to use it.
>>> On Mar 23, 2017, at 6:27 PM, Drew Crawford via swift-evolution
>>> <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>>> Sent from my iPhone
>>> On Mar 23, 2017, at 6:41 PM, David Hart <david at hartbit.com
>>> <mailto:david at hartbit.com>> wrote:
>>>> I have difficulties imagining a submodule proposal that could allow us
>>>> to eliminate fileprivate. Care to give an example?
>>> The obvious example would be Rust.  Rust has exactly two visibilities,
>>> and merely one keyword.  By default, members are "private" which is
>>> visible inside the module (so, like Swift's internal). The "public"
>>> keyword is similar to Swift.
>>> The reason this works is that unlike in Swift where a module is something
>>> like a library or framework (Rust calls those "crates"), in Rust modules
>>> in are (explicitly) lexically scoped; a "mod myscope {}" module can be
>>> created for the portion of the file for which the member should be
>>> visible and it won't be visible outside that scope. Likewise,
>>> "fileprivate" can be achieved by enclosing the file in a "mod MyFile {}".
>>> And like all lexical scopes, they can be recursively nested to arbitrary
>>> depth to achieve any number of visibility behaviors (e.g., declare a
>>> module for the first half of two files) that would require complex new
>>> keywords to achieve in Swift. Finally there are some shortcut features
>>> like the ability to infer a module structure from the file system.
>>> In Swift, modules are presently tied to libraries/frameworks in a 1:1
>>> way. Because of this we lack the flexibility of recursively nestable
>>> modules of other languages and this is the underlying problem that
>>> motivates both scoped/private and fileprivate.  If we fixed that, we
>>> would actually not need either keyword.
>>> http://rustbyexample.com/mod/visibility.html
>>> https://doc.rust-lang.org/book/crates-and-modules.html
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