Unity3D & YamlDotNet Deserializing Data into Monobehaviour-derived classes - unity3d

Question

I'm trying to serialize data into / from my classes, derived from MonoBehaviour, which cannot be created from client code (e.g., with the new keyword), but rather must be created by a Unity3D-specific method, GameObject.AddComponent<T>(). How can I use the YamlDotNet framework to populate my classes with values without having to create an adapter for each one? Is there some sort of built-in adapter that I can configure, such that YamlDotNet doesn't instantiate the class it's trying to serialize to?
A typical file might contain a mapping of items, e.g.,
%YAML 1.1
%TAG !invt! _PathwaysEngine.Inventory.
%TAG !intf! _PathwaysEngine.Adventure.
---
Backpack_01: !invt!Item+yml
mass: 2
desc:
nouns: /^bag|(back)?pack|sack|container$/
description: |
Your backpack is only slightly worn, and...
rand_descriptions:
- "It's flaps twirl in the breeze."
- "You stare at it. You feel enriched."
MagLite_LR05: !invt!Lamp+yml
cost: 56
mass: 2
time: 5760
desc:
nouns: /^light|flashlight|maglite|lr_05$/
description: |
On the side of this flashlight is a label...
(Type "light" to turn it on and off.)
...
Where the tags are the fully specified class names of my Items, e.g., PathwaysEngine.Inventory.Lamp+yml, PathwaysEngine is the namespace I use for my game engine code, Inventory deals with items & whatnot, and Lamp+yml is how the compiler denotes a nested class, yml inside Lamp. Lamp+yml might look like this:
public partial class Lamp : Item, IWearable {
public new class yml : Item.yml {
public float time {get;set;}
public void Deserialize(Lamp o) {
base.Deserialize((Item) o);
o.time = time;
}
}
}
I call Deserialize() on all objects that derive from Thing from Awake(), i.e., once the MonoBehaviour classes exist in the game. Elsewhere, I've already created a pretty complicated Dictionary filled with objects of type Someclass+yml, and then Deserialize takes an instance of the real, runtime class Someclass and populates it with values. There's got to be a cleaner way to do this, right?
How can I:
Tell the Deserializer what my classes are?
See the second edit for a good solution for the above issue
Get the data without it attempting to create my MonoBehaviour-derived classes?
Edit: I've since worked at the problem, and have found out a good way of dealing with custom data (in my particular case of trying to parse regexes out of my data, and having them not be considered strings & therefore, un-castable to regex) is to use a IYamlTypeConverter for that particular string. Using YamlDotNet with Unity3D MonoBehaviours, however, is still an issue.
Another Edit: The above examples use a pretty ugly way of determining types. In my case, the best thing to do was to register the tags first with the deserializer, e.g.,
var pre = "tag:yaml.org,2002:";
var tags = new Dictionary<string,Type> {
{ "regex", typeof(Regex) },
{ "date", typeof(DateTime) },
{ "item", typeof(Item) }};
foreach (var tag in tags)
deserializer.RegisterTagMapping(
pre+tag.Key, tag.Value);
Then, I use the !!tag notation in the *.yml file, e.g.,
%YAML 1.1
---
Special Item: !!item
nouns: /thing|item|object/
someBoolean: true
Start Date: !!date 2015-12-17
some regex: !!regex /matches\s+whatever/
...

Answer 1

You can pass a custom implementation of IObjectFactory to the constructor of the Deserializer class. Every time the deserializer needs to create an instance of an object, it will use the IObjectFactory to create it.
Notice that your factory will be responsible for creating instances of every type that is deserialized. The easiest way to implement it is to create a decorator around DefaultObjectFactory, such as:
class UnityObjectFactory : IObjectFactory
{
private readonly DefaultObjectFactory DefaultFactory =
new DefaultObjectFactory();
public object Create(Type type)
{
// You can use specific types manually
if (type == typeof(MyCustomType))
{
return GameObject.AddComponent<MyCustomType>();
}
// Or use a marker interface
else if (typeof(IMyMarkerInterface).IsAssignableFrom(type))
{
return typeof(GameObject)
.GetMethod("AddComponent")
.MakeGenericMethod(type)
.Invoke();
}
// Delegate unknown types to the default factory
else
{
return DefaultFactory(type);
}
}
}