Iatheto

Iatheto is a minimal JSON framework that serializes to and from Apple's Codable. By now there are many such frameworks, but Iatheto is one of the oldest — it predates Codable — with a very tiny implementation.

Iatheto supports only those types directly supported by JSON and no others. To handle a date, for instance, you must first turn it into a string.

Literals

Like most modern Swift JSON frameworks, Iatheto supports the usual literal assignments:

var json: JSON = nil // Produces JSON.null
json = "json" // Produces JSON.string("json")
json = ["array": [1, 2, 3]] // Produces JSON.object(["array": JSON.array([1, 2, 3])])

Attributes

Iatheto has nilable properties — getters and setters — which can be used to get typed values.

let json: JSON = "json"
let s = json.string // If json is JSON.string, then s will be "json", otherwise nil. 

Assigning nil to one of these properties changes the receiver to JSON.null:

var json: JSON = "json"
json.string = nil // json is now JSON.null

Subscripts

Iatheto has exactly the subscripts you'd expect:

let json: JSON = ["foo": ["bar"]]
let s = json["foo"]?[0]?.string // If the types work out s will be "bar", otherwise nil.

Assignment through the subscripts is possible. Assigning nil to an array subscript produces JSON.null. However, assigning nil through an object subscript removes the entry from the underlying object. To specifically set to JSON.null, assign that particular value.

var json: JSON = ["foo": ["bar"]]
json["foo"]?[0] = nil // Produces {"foo": [null]}
json["foo"] = .null // Produces {"foo": null}
json["foo"] = nil // Produces {}

During a subscript assignment, if the underlying value is not an array or object, it becomes one:

var json: JSON = nil
json["foo"] = "bar" // Produces {"foo": "bar"}
json["foo"]?.int = 3 // Produces {"foo": 3}

Encoding

Iatheto's JSON type supports initialization by many kinds of literals, so the syntax is natural.

let json: JSON = ["first_name": "Murray", "last_name": "Rothbard", "born": 1926, "died": 1995]
let encoder = JSONEncoder()
let data = try encoder.encode(json)

Decoding

Decoding is as straightforward as encoding:

let decoder = JSONDecoder()
let json = try decoder.decode(JSON.self, from: data)

What's a Iatheto?

"Iatheto" comes from the Greek ἰαθήτω, "she shall be healed", which in turn comes the verb ἰάομαι "to heal". This verb is the origin of the name Ἰάσων "Jason".