Helpful labels for serialized arrays accessed by enum types

EnumIndexedArray.cs

using System;
using System.Text.RegularExpressions;
using UnityEngine;
#if UNITY_EDITOR
using UnityEditor;

#endif

namespace com.hololabs
{
    /// <summary>
    /// When you're serializing arrays or lists to be accessed by the underlying value of an enum,
    /// using the [EnumIndexedArray] annotation will allow the inspector to label array indices correctly
    /// as the enum value rather than as "Element 0".
    /// </summary>
    /// <example>
    /// enum Direction { Left, Right, Up, Down }
    /// 
    /// [SerializedField]
    /// [EnumIndexedArray(typeof(Direction))]
    /// public float[] SpeedForDirection;
    /// </example>
    public class EnumIndexedArray : PropertyAttribute
    {
        public readonly Type indexType;

        public EnumIndexedArray(Type indexType)
        {
            this.indexType = indexType;
        }
    }

#if UNITY_EDITOR
    [CustomPropertyDrawer(typeof(EnumIndexedArray))]
    public class EnumIndexedArrayInspector : PropertyDrawer
    {
        static readonly Regex EXTRACT_INDEX = new Regex(@"\.data\[(\d+)\]$");

        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
        {
            Match match = EXTRACT_INDEX.Match(property.propertyPath);
            if (match.Success)
            {
                Type enumType = ((EnumIndexedArray) this.attribute).indexType;
                int arrayIndex = int.Parse(match.Groups[1].Value);
                string enumName = Enum.GetName(enumType, arrayIndex);
                if (enumName != null)
                {
                    label = new GUIContent(enumName);
                }
            }
            EditorGUI.PropertyField(position, property, label);
        }
    }
#endif
}

Accepting suggestions for better ways to find the underlying array index...