Support Decodable/Encodable (Swift 4)

[Eric Marchand]

In the past, I try to make some utility functions to work with NSCoding (branch feature-nscoding), write and read JSON

In swift 4 Decodable/Encodable (and Codable) allow to have a better interface to serialize objects

We can

• write to file an Encodable object
• write to file an array of Encodable objects
• read from file an Decodable object
• read from file an array of Decodable objects

That could be done only after merging #49

[Nikolai Vazquez]

These would be good changes to have but behind #if swift(>=3.2).

[Eric Marchand]

I make a class FileKit to get shared JSON/PropertyList encoder/decoder
And also for easy to use functions

try FileKit.write(encodable, to: .userTemporary + "test")
let decodable: MyClass = try FileKit.read(from:  .userTemporary + "test")

Array of Codable are codable, so the same functions work

---

I add protocols JSONReadable, JSONWritable (or PropertyListReadable/PropertyListWritable) to be able to implement Readable and Writable and create File with specific type just by implementing protocols
(an alias name could be added like JSONReadableWritable if necessary for JSONWritable, JSONReadable)
This protocol define the encoder or decoder to use. By default the one shared by FileKit

struct TestJSONCodable: Codable {
    let string: String
    let integer: Int
}
extension TestJSONCodable: JSONWritable, JSONReadable {}

let encodable = TestJSONCodable(string: "test", integer: 9)
let codableFile = File<TestJSONCodable>(path:  .userTemporary + "testcodable.json")
try codableFile.write(encodable)
let decodable: TestJSONCodable = try codableFile.read()

[Eric Marchand]

committed but need some doc in README