EnergyCompressor.cs

using UnityEngine;
using System.Collections;

public class EnergyCompressor : Weapon {
	public virtual string GetDisplayName() {
		return "energy compressor";
	}
}

Player.cs

using UnityEngine;
using System.Collections;

public class Player : MonoBehaviour {
	public const short max_weapons = 3;
	public string defaultWeaponClass = "EnergyCompressor";

	public Weapon[] equippedWeapons;
	public Weapon currentWeapon {
		get {
			if (equippedWeapons != null && equippedWeapons[0])
				return equippedWeapons[0];
			
			return null;
		}
	}
	
	void Start() {
		equippedWeapons = new Weapon[max_weapons];
		equippedWeapons[0] = (EnergyCompressor) ScriptableObject.CreateInstance(defaultWeaponClass);
	}

	void OnGUI() {
		if (currentWeapon != null)
			GUILayout.Label("Current weapon: " + currentWeapon.GetDisplayName());
	}
}

Weapon.cs

using UnityEngine;
using System.Collections;

public class Weapon : ScriptableObject {
	public virtual string GetDisplayName() {
		return "unknown weapon";
	}
}