Hi David and Geordie,
That approach won’t work — encoders and decoders only work directly
with concrete `Codable` types (e.g. `String`, `Int`, `MyFoo` [where
`MyFoo` is `Codable], etc.).
This is by design: since there is no type information stored in the JSON
payload, there isn’t necessarily a way to tell how to decode the type
you’re looking at, so asking for a general `Codable` isn’t helpful.
Since it’s unlikely that what you truly need is a `[String : Any]` but
really a `[String : <one of String, Int, MyFoo, etc.>]`, one easy way to
decode this type is to create a wrapper `enum` or similar which
overrides `init(from:)` to be able to decode from one of those types.
You can then ask to decode a `[String : MyWrapperType]` and use that
instead.
What types are you expecting in the dictionary?
— Itai
On 19 Oct 2017, at 18:11, David Baraff via swift-users wrote:
I’ll try. Is that cast smart enough to apply recursively? We shall
see.
Sent from my iPad
On Oct 19, 2017, at 7:34 AM, Geordie Jay <geo...@gmail.com> wrote:
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 <davidbar...@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 <geo...@gmail.com> wrote:
David Baraff via swift-users <swift-users@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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