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LinkedList: Codable protocol and references

Frank-Peter Poschmann Swift 23.08.201910.09.2019Codable, data structure, linked list, NSCoding, reference type, serialization 0 Kommentare

Maybe you have read my series of posts about LinkedLists. It was great fun for me to put these things together, but recently, I stumbled over a problem with serialisation, esp. the Codable protocol and references to objects. In Swift 5 there are two Encoder/Decoder pairs available:

PropertyListEncoder/PropertyListDecoder
JSONEncoder/JSONDecoder

It turns out that these encoders are not really suitable for archiving object graphs because they expand all references to objects, i.e. put the objects instead of the references in the archive. If you have a simple tree of objects and you do not care about doublets that may be fine but as soon as you have loops in your object graph you are in trouble. Encoding such a graph with these two encoders lead to an endless loop. This may happen quite frequently; just think about delegation where you typically have references of the delegate and its master against each other.

Linked Lists in Swift (4)

Frank-Peter Poschmann Swift 03.04.2018Codable, data structure, linked list, serialization 0 Kommentare

So, this is my last post in this series about linked lists. There is one last thing we have to add: serialising for storing our linked list on disk or sending over a network. As you have seen in this post, serialising has become much easier in Swift 4. If we make the requirement that our generic class T is already Codable the rest is quite easy. Weiterlesen

Linked Lists in Swift (3)

Frank-Peter Poschmann Swift 12.03.201801.11.2018data structure, linked list 0 Kommentare

This is my third post about linked lists in Swift. In the previous post we’ve made our linked list a little bit more „Swifty“. Today I want to introduce some more convenient methods to make life easier.

Linked Lists in Swift (2)

Frank-Peter Poschmann Swift 23.02.201823.02.2018data structure, iterator, linked list, sequence, subscript 0 Kommentare

And here comes my second post in the series about linked lists in Swift. In the first post we have implemented the basics to make our linked list work. Now, let’s make our linked list a little bit more „Swifty“.

Linked Lists in Swift (1)

Frank-Peter Poschmann Swift 05.02.201804.03.2018data structure, linked list, reference type, value type 0 Kommentare

This is the first post of my upcoming series devoted to linked lists. I like this data structure very much because of its elegance and efficiency in situations where you have to insert and remove objects quite often and randomly. Unfortunately there is no standard data type „Linked List“ in Swift, so we have to build one by ourself. That’s not too difficult and there are quite a few example implementations in the web (e.g. from Chris Pilcher or Hugo Tunius). I’ll take these as a starting point and add some of my own thinkings and optimisations.