How do I create a Unity 3D UI text element in an F# script? - unity3d

Question

I'm attempting to create some ui elements in my F# script that is attached to a camera in Unity 3d. I know how to do this in C# but I'm not quite sure how to do it in F#.
Here's a simple C# example:
using UnityEngine;
using UnityEngine.UI;
public class CameraController : MonoBehaviour {
public Text uiText;
void Start ()
{
uiText.text = "Hello world!";
}
void Update ()
{
}
}
Now, here's my F# code. I've added comments that displays the compiler error I get when attempting to create a text element, This type has no accessible constructors.
namespace GameLogic
open UnityEngine
open UnityEngine.UI
type CameraController() =
inherit MonoBehaviour()
member this.uiText = Text // Compiler Error: This type has no accessible constructors
member this.Start() =
let uiText = Text // Compiler Error: This Type has no accessible constructors
()
member this.Update() =
()
It seems like F# implicitly calls a constructor method on Unity's Text object.
So, how can I create a ui text element in an F# script? Thanks for any and all help.
Kurt

Answer 1

In your C# code, the uiText member is getting initialized with null, which is the default for C#. In F#, there is no "default", you have to write the initial value explicitly:
member this.uiText: Text = null
This will compile, but won't give you the desired result. This syntax will create a read-only property that always returns null. In order to create a read/write property with initial value, you have to use member val:
member val uiText: Text = null with get, set
The 'get, set' part in there serves for clarification that you want the property to be readable and writable. Without it (by default), the property will be read-only.
For a complete description of how properties work in F#, see MSDN.

Answer 2

I ended up using a mutable let binding that specifies it is of type Text and its initial value is null. I then added the SerializeField attribute in order to associate UI Text elements in the Unity editor with the script.
Below is a simple example.
namespace GameLogic
open UnityEngine
open UnityEngine.UI
type CameraController() =
inherit MonoBehaviour()
[<SerializeField>]
let mutable uiText : Text = null
member this.Start() =
uiText.text <- "hello world!"
()
member this.Update() =
()