[swift-users] dealing with heterogenous lists/dictionary with Codable

[Geordie Jay]

I mean can you do something along the lines of

let codableDict = stringAnyDict as? [String : Codable]

?

I’m not at a computer to test it myself




David Baraff <davidbaraff at gmail.com> schrieb am Do. 19. Okt. 2017 um 15:45:

> That’s exactly what I want.  The ironic part is that I got my dictionary
> by decoding a Json file.  If that’s where my dictionary came from, is there
> a simple way of coercing the Json serialization routines to give me back
> codables, rather than Anys?
>
>
> Sent from my iPad
>
> On Oct 19, 2017, at 3:38 AM, Geordie Jay <geojay at gmail.com> wrote:
>
>
> David Baraff via swift-users <swift-users at swift.org> schrieb am Do. 19.
> Okt. 2017 um 03:47:
>
>> So I have simple structs like this:
>>
>>         struct Library: Codable {
>>                 let domain: String
>>                 let unit: String
>>         }
>>
>> and it’s super-simple to serialize.  Yay.
>>
>> But:
>>
>>         struct LibraryGroup : Codable {         // I wish...
>>            let libraries: [Library]
>>            let someDict: [String : Any]
>>         }
>>
>
> I haven’t tried this, but is it possible to have a dictionary of [String :
> Codable] ? Because that’s exactly the type requirements you’re describing,
> no?
>
> Geordie
>
>
>> So what I’m looking for is something where if the values in someDict are
>> themselves Codable, I can serialize things, and if they’re not, I can’t.
>> In my previous scheme, I was using NSKeyedArchiver to serialize everything,
>> manualy, including someDict; in trying to switch to Codable I ran smack
>> into the fact that Codable wants to know what all the types are, in advance.
>>
>> Am I just stuck?  How do I get the best of both worlds, where the
>> compiler can make use of the fact that it can see the data types of my
>> structures, while still being able to serialize heterogenous data like is
>> found in LibraryGroup?
>>
>> Is my only alternative to write a custom coder for LibraryGroup?  Is
>> there any hope I could teach Codable what to do with
>>         [String: Any]
>>
>> ?
>>
>>
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>
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