InputManager.cs

using UnityEngine;

public class InputManager : MonoBehaviour
{
    static readonly Vector2 x1 = new Vector2(1f, 0f);
    public abstract class InputBase
    {
        public abstract Vector2 Get();
        static public implicit operator Vector2(InputBase inputTypeBase){
            return inputTypeBase.Get();
        }

        static public implicit operator float(InputBase inputTypeBase)
        {
            return inputTypeBase.Get().magnitude;
        }

        static public implicit operator bool(InputBase inputTypeBase)
        {
            return inputTypeBase.Get().magnitude != 0;
        }
    }

    class KeyInput : InputBase
    {

        readonly KeyCode key;
        readonly Vector2 direction;

        public KeyInput(KeyCode key) : this(key, x1) { }
        public KeyInput(KeyCode key, Vector2 direction) { 
            this.key = key;
            this.direction = direction;
        }

        public override Vector2 Get()
        {
            return Input.GetKey(key) ? direction : Vector2.zero;
        }
    }

    class Button : InputBase
    {
        InputBase[] mappings;
        public Button(params InputBase[] mappings)
        {
            this.mappings = mappings;
        }
        public override Vector2 Get()
        {
            Vector2 v;
            foreach(var mapping in mappings)
            {
                v = mapping.Get();
                if (v != Vector2.zero)
                    return x1;
            }
            return Vector2.zero;
        }
    }

    public enum Inputs {Primary, Secondary, Look, Move, End}
    InputBase[] inputMap = new InputBase[(int)Inputs.End];

    public InputBase GetInput(Inputs input) { return inputMap[(int)input]; }
    public InputBase this[Inputs input] { get { return GetInput(input); } }

    // Start is called before the first frame update
    void Start()
    {
        inputMap[(int)Inputs.Primary] = new Button(new KeyInput(KeyCode.E), new KeyInput(KeyCode.Underscore));
    }

    // Update is called once per frame
    void Update()
    {
        bool E_ = this[Inputs.Primary];
    }
}