Optional Order parameter for GroupAttribute

.gitignore

@@ -1,2 +1,5 @@
 # DS_Store
 *.DS_Store
+
+# Covers JetBrains IDEs
+.idea

Alchemy/Assets/Alchemy/Editor/AlchemyEditorUtility.cs

@@ -25,6 +25,7 @@ internal static AlchemyGroupDrawer CreateGroupDrawer(PropertyGroupAttribute attr
             var drawerType = FindGroupDrawerType(attribute);
             var drawer = (AlchemyGroupDrawer)Activator.CreateInstance(drawerType);
             drawer.SetUniqueId("AlchemyGroupId_" + targetType.FullName + "_" + attribute.GroupPath);
+            drawer.SetOrder(attribute.Order);
             return drawer;
         }
     }

Alchemy/Assets/Alchemy/Editor/AlchemyGroupDrawer.cs

@@ -8,6 +8,16 @@ namespace Alchemy.Editor
     /// </summary>
     public abstract class AlchemyGroupDrawer
     {
+        /// <summary>
+        /// ID used to identify the group.
+        /// </summary>
+        public string UniqueId => _uniqueId;
+
+        /// <summary>
+        /// Drawing order
+        /// </summary>
+        public int Order => _order;
+
         /// <summary>
         /// Create a visual element that will be the root of the group.
         /// </summary>
@@ -20,16 +30,17 @@ public abstract class AlchemyGroupDrawer
         /// <param name="attribute">Target attribute</param>
         public virtual VisualElement GetGroupElement(Attribute attribute) => null;
 
-        /// <summary>
-        /// ID used to identify the group.
-        /// </summary>
-        public string UniqueId => uniqueId;
-
-        string uniqueId;
+        private string _uniqueId;
+        private int _order;
 
         internal void SetUniqueId(string id)
         {
-            this.uniqueId = id;
+            _uniqueId = id;
+        }
+
+        internal void SetOrder(int order)
+        {
+            _order = order;
         }
     }
 }

Alchemy/Assets/Alchemy/Editor/Internal/InspectorHelper.cs

@@ -44,6 +44,7 @@ public GroupNode Find(Func<GroupNode, bool> predicate)
             public void Add(GroupNode node)
             {
                 children.Add(node);
+                children.Sort((a, b) => a.drawer.Order.CompareTo(b.drawer.Order));
                 node.Parent = this;
             }
 

Alchemy/Assets/Alchemy/Runtime/Inspector/GroupAttributes.cs

@@ -2,24 +2,24 @@ namespace Alchemy.Inspector
 {
     public sealed class GroupAttribute : PropertyGroupAttribute
     {
-        public GroupAttribute() : base() { }
-        public GroupAttribute(string groupPath) : base(groupPath) { }
+        public GroupAttribute(int order = 0) : base(order) { }
+        public GroupAttribute(string groupPath, int order = 0) : base(groupPath, order) { }
     }
 
     public sealed class BoxGroupAttribute : PropertyGroupAttribute
     {
-        public BoxGroupAttribute() : base() { }
-        public BoxGroupAttribute(string groupPath) : base(groupPath) { }
+        public BoxGroupAttribute(int order = 0) : base(order) { }
+        public BoxGroupAttribute(string groupPath, int order = 0) : base(groupPath, order) { }
     }
 
     public sealed class TabGroupAttribute : PropertyGroupAttribute
     {
-        public TabGroupAttribute(string tabName) : base()
+        public TabGroupAttribute(string tabName, int order = 0) : base(order)
         {
             TabName = tabName;
         }
 
-        public TabGroupAttribute(string groupPath, string tabName) : base(groupPath)
+        public TabGroupAttribute(string groupPath, string tabName, int order = 0) : base(groupPath, order)
         {
             TabName = tabName;
         }
@@ -29,19 +29,19 @@ public TabGroupAttribute(string groupPath, string tabName) : base(groupPath)
 
     public sealed class FoldoutGroupAttribute : PropertyGroupAttribute
     {
-        public FoldoutGroupAttribute() : base() { }
-        public FoldoutGroupAttribute(string groupPath) : base(groupPath) { }
+        public FoldoutGroupAttribute(int order = 0) : base(order) { }
+        public FoldoutGroupAttribute(string groupPath, int order = 0) : base(groupPath, order) { }
     }
 
     public sealed class HorizontalGroupAttribute : PropertyGroupAttribute
     {
-        public HorizontalGroupAttribute() : base() { }
-        public HorizontalGroupAttribute(string groupPath) : base(groupPath) { }
+        public HorizontalGroupAttribute(int order = 0) : base(order) { }
+        public HorizontalGroupAttribute(string groupPath, int order = 0) : base(groupPath, order) { }
     }
 
     public sealed class InlineGroupAttribute : PropertyGroupAttribute
     {
-        public InlineGroupAttribute() : base() { }
-        public InlineGroupAttribute(string groupPath) : base(groupPath) { }
+        public InlineGroupAttribute(int order = 0) : base(order) { }
+        public InlineGroupAttribute(string groupPath, int order = 0) : base(groupPath, order) { }
     }
 }

Alchemy/Assets/Alchemy/Runtime/Inspector/PropertyGroupAttribute.cs

@@ -7,16 +7,20 @@ namespace Alchemy.Inspector
     /// </summary>
     public abstract class PropertyGroupAttribute : Attribute
     {
-        public PropertyGroupAttribute()
+        public PropertyGroupAttribute(int order = 0)
         {
             GroupPath = string.Empty;
+            Order = order;
         }
 
-        public PropertyGroupAttribute(string groupPath)
+        public PropertyGroupAttribute(string groupPath, int order = 0)
         {
             GroupPath = groupPath;
+            Order = order;
         }
-
+        
         public string GroupPath { get; }
+
+        public int Order { get; }
     }
 }

Alchemy/Assets/Tests/GroupOrderTest.cs

@@ -0,0 +1,41 @@
+using Alchemy.Inspector;
+using UnityEngine;
+
+public class GroupOrderTest : MonoBehaviour
+{
+    [Group("Group3", 30)]
+    [SerializeField]
+    private float _valueFloatGroup3;
+
+    [Group("Group3", 30)]
+    [SerializeField]
+    private string _valueStringGroup3;
+
+    [Group("Group2", 20)]
+    [SerializeField]
+    private string _valueStringGroup2;
+
+    [Group("Group1", 10)]
+    [SerializeField]
+    private float _valueFloatGroup1;
+
+    [Group("Group1", 10)]
+    [SerializeField]
+    private string _valueStringGroup1;
+
+    [Group("Group2", 20)]
+    [SerializeField]
+    private float _valueFloatGroup2;
+
+    [Group("Group3" , 30)]
+    [SerializeField]
+    private bool _valueBoolGroup3;
+
+    [Group("Group2", 20)]
+    [SerializeField]
+    private bool _valueBoolGroup2;
+
+    [Group("Group1", 10)]
+    [SerializeField]
+    private bool _valueBoolGroup1;
+}