ValueCodable is a swift library to decode data of unknown structure in a type safe way.
For instance, say you have a yml file with the following content
name: foo
data:
obj:
a: 1
b: two
list:
- 1
- two
- foo: bar
where the format of data is unknown beforehand. It is not straightforward to write a decoder for the arbitrary data structure.
Whith ValueCodable, the decoding is quite simple:
let s = """
name: foo
data:
obj:
a: 1
b: two
list:
- 1
- two
- foo: bar
"""
struct Test: Decodable {
let name: String
// capture the unstructure data as "Value"
let data: Value
}
let t = try YAMLDecoder().decode(Test.self, from: s)
// access "data" via subscript
print(t.data["obj"]) // Optional(["a": 1, "b": "two"])
print(t.data["list"]) // Optional([1, "two", ["foo": "bar"]])
print(t.data["list"]?[0]) // Optional(1)
// act on the decoded types
switch t.data["list"]?[2] {
case let .some(.dictionary(dict)):
print(dict) // ["foo": "bar"]
default:
print("unhandled type")
}
// access propertyies via key paths
print(t.data["obj.b"]) // Optional("two")
print(t.data["list[0]"]) // Optional(1)
print(t.data["list[2].foo"]) // Optional("bar")
Value currently supports the following types:
public enum Value: Equatable {
case bool(Bool)
case int(Int)
case string(String)
case double(Double)
case dictionary([Key: Value])
case array([Value])
case null
}
When decoding, ValueCodable will attempt to decode into the most suitable type.