[swift-users] Recursive Enums and String Literals

[Rick Gigger]

I just realized that two of the cases in the enum were wrong. They should
have been:

    indirect case anyDict([String:RecursiveAny])
    indirect case anyArr([RecursiveAny])

That change forced me to update some of the enum methods, but it
didn't end up changing the compile status of any of the tests below
it.


On Sun, Dec 27, 2015 at 3:14 AM Rick Gigger <swift at rickgigger.com> wrote:

> I am trying to create an enum that will allow me to create literals that
> combine Int, Double and String types, as well as any Array of any
> combination of those, and any Dictionary mapping a String to any
> combination of those. And make it nestable.
>
> First I have the enum itself, and then several examples. Everything
> complies cleanly except for dict4 and dict5.
>
> Is type inference not expected to work for recursive enums? Or is this a
> bug in the compiler? If not is there any way to do this in pure swift that
> will compile?
>
> I realize that it's sort of unswifty to have such unstructured, stringly
> typed data like this. But in a pinch sometimes it's useful.
>
> Copy and paste this into a Playground to see the error message.
> (Contextual type 'protocol <>' cannot be used with array literal and
> Contextual type 'protocol <>' cannot be used with dictionary literal)
>
> enum RecursiveAny: StringLiteralConvertible, ArrayLiteralConvertible,
> IntegerLiteralConvertible, BooleanLiteralConvertible,
> FloatLiteralConvertible, DictionaryLiteralConvertible {
>
>     case any(Any)
>
>     indirect case anyDict([String:Any])
>
>     indirect case anyArr([Any])
>
>
>
>     // string literal convertible
>
>     init(stringLiteral value: String) {
>
>         self = .any(value)
>
>     }
>
>
>
>     init(extendedGraphemeClusterLiteral value: String) {
>
>         self = .any(value)
>
>     }
>
>
>
>     init(unicodeScalarLiteral value: String) {
>
>         self = .any(value)
>
>     }
>
>
>
>     // array literal convertible
>
>     init(arrayLiteral elements: Any...) {
>
>         self = .anyArr(elements)
>
>     }
>
>
>
>     init(dictionaryLiteral elements: (String, Any)...) {
>
>         var dict = [String:Any]()
>
>         for (key, value) in elements {
>
>             dict[key] = value
>
>         }
>
>         self = .anyDict(dict)
>
>     }
>
>
>
>     // integer literal convertible
>
>     init(integerLiteral value: Int) {
>
>         self = .any(value)
>
>     }
>
>
>
>     // boolean literal convertible
>
>     init(booleanLiteral value: Bool) {
>
>         self = .any(value)
>
>     }
>
>
>
>     // float literal convertible
>
>     init(floatLiteral value: Double) {
>
>         self = .any(value)
>
>     }
>
> }
>
>
> let string: RecursiveAny = "asdf"
>
> let int: RecursiveAny = 3
>
> let float: RecursiveAny = 5.6
>
> let array: RecursiveAny = ["asdf", 3, 5.6]
>
> let dict: RecursiveAny = [
>
>     "string": "asdf",
>
>     "int": 3,
>
>     "float": 5.6
>
> ]
>
> let dict2: RecursiveAny = [
>
>     "string": "asdf",
>
>     "int": 3,
>
>     "float": 5.6,
>
>     "array": array
>
> ]
>
> let dict3: RecursiveAny = [
>
>     "string": "asdf",
>
>     "int": 3,
>
>     "float": 5.6,
>
>     "array": dict
>
> ]
>
> let dict4: RecursiveAny = [
>
>     "string": "asdf",
>
>     "int": 3,
>
>     "float": 5.6,
>
>     "array": ["asdf", 3, 5.6]
>
> ]
>
> let dict5: RecursiveAny = [
>
>     "string": "asdf",
>
>     "int": 3,
>
>     "float": 5.6,
>
>     "dict": [
>
>         "string": "asdf",
>
>         "int": 3,
>
>         "float": 5.6
>
>     ]
>
> ]
>
>
> let dict6: RecursiveAny = [
>
>     "string": "asdf",
>
>     "int": 3,
>
>     "float": 5.6,
>
>     "array": RecursiveAny.anyArr(["asdf", 3, 5.6])
>
> ]
>
> let dict7: RecursiveAny = [
>
>     "string": "asdf",
>
>     "int": 3,
>
>     "float": 5.6,
>
>     "dict": RecursiveAny.anyDict([
>
>         "string": "asdf",
>
>         "int": 3,
>
>         "float": 5.6
>
>     ])
>
> ]
>
>
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