Hello Swifters,
While working on some framework programming, I had this idea that I would like to share with you.
If some other people like it, I would be more than happy to write a proposal.
Here is a little draft I wrote as a starting point to discuss.
Sorry if there is mistakes, I am not an english native speaker.
Thank you for your feedback.
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Swift proposal: Access modifier blocks
This proposal introduces a refinement of the way to define access modifier and visibility scope.
The current keywords private, internal and public are nice, simple to use and makes sense. But, especially in the context of framework development, it can quickly becomes messy and confusing to define the visibility for each member variable, function or enum. Also it takes more time to write and is not ideal to visualize the public interface of a class.
If a class A has only a few members, that’s ok to write
class A {
public var member1: Int
var member2: Int
private var member3: Int
}
With a bigger class B, it will looks far less nice
class B {
public var member1: Int
var member2: Int
private var member3: Int
public var member4: Int
var member5: Int
private var member6: Int
public var member7: Int
var member8: Int
private var member9: Int
public var member10: Int
private var member11: Int
var member12: Int
public var member13: Int
var member14: Int
private var member15: Int
}
And now, it’s really messy, takes more time to write and we need to think twice to visualize what could be the public interface of our framework.
The purpose of this proposal is to allow the definition of the access modifiers for a block of declarations.
Then our class B could be:
class B {
// Ok then this is part of the public interface of my framework
public {
var member1: Int
var member4: Int
var member7: Int
var member10: Int
var member13: Int
}
// This can be used anywhere in my framework
internal {
var member2: Int
var member5: Int
var member8: Int
var member12: Int
var member14: Int
}
// Here remains my private stuff. Don’t touch it ! Leave me alone ! My preciouuusss
private {
var member3: Int
var member6: Int
var member9: Int
var member11: Int
var member15: Int
}
}
It increases readability, avoid to write many times the same keywords, which is quiet boring, and helps visualizing the architecture of the framework by highlighting what can create a dependency with other classes inside the framework and with code outside of the framework.
It might also be useful in protocols. For exemple, a protocol could define a set of methods that can be called only inside the framework and another public one that can be called from outside of the framework.
Classes defined outside of the framework could only implement the public stuff in the protocol.
It would have no impact on the existing code as the existing private/internal/public on every single line would still work outside of an access modifier block so developers could move to use this smoothly.
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Please, let me know if you like the idea.
Cheers,
Raph