Add YGValue property drawer

Editor/Gilzoide.FlexUi.Editor.asmdef

@@ -0,0 +1,18 @@
+{
+    "name": "Gilzoide.FlexUi.Editor",
+    "rootNamespace": "Gilzoide.FlexUi.Editor",
+    "references": [
+        "GUID:f5764d172907845189231762597f67e6"
+    ],
+    "includePlatforms": [
+        "Editor"
+    ],
+    "excludePlatforms": [],
+    "allowUnsafeCode": false,
+    "overrideReferences": false,
+    "precompiledReferences": [],
+    "autoReferenced": true,
+    "defineConstraints": [],
+    "versionDefines": [],
+    "noEngineReferences": false
+}

Editor/YGValuePropertyDrawer.cs

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+using System;
+using Gilzoide.FlexUi.Yoga;
+using UnityEditor;
+using UnityEngine;
+
+namespace Gilzoide.FlexUi.Editor
+{
+    [CustomPropertyDrawer(typeof(YGValue))]
+    public class YGValuePropertyDrawer : PropertyDrawer
+    {
+        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
+        {
+            string value = GetValueAsString(property);
+            string newValue = EditorGUI.DelayedTextField(position, label, value).ToLowerInvariant().Trim();
+            if (newValue == "auto")
+            {
+                SetValue(property, YGValue.Auto);
+            }
+            else if (newValue == "" || newValue == "none" || newValue == "undefined")
+            {
+                SetValue(property, YGValue.Undefined);
+            }
+            else if (newValue.EndsWith('%') && float.TryParse(newValue.Substring(0, newValue.Length - 1), out float percentValue))
+            {
+                SetValue(property, new YGValue(percentValue, Unit.Percent));
+            }
+            else if (float.TryParse(newValue, out float pointValue))
+            {
+                SetValue(property, new YGValue(pointValue, Unit.Point));
+            }
+        }
+
+        public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
+        {
+            return EditorGUI.GetPropertyHeight(SerializedPropertyType.String, label);
+        }
+
+        private static string GetValueAsString(SerializedProperty property)
+        {
+            int unit = property.FindPropertyRelative(nameof(YGValue.Unit)).enumValueIndex;
+            float value = property.FindPropertyRelative(nameof(YGValue.Value)).floatValue;
+            switch ((Unit) unit)
+            {
+                case Unit.Undefined:
+                    return "none";
+
+                case Unit.Point:
+                    if (float.IsNaN(value))
+                    {
+                        return "none";
+                    }
+                    else
+                    {
+                        return value.ToString();
+                    }
+
+                case Unit.Percent:
+                    if (float.IsNaN(value))
+                    {
+                        return "none";
+                    }
+                    else
+                    {
+                        return value.ToString() + '%';
+                    }
+
+                case Unit.Auto:
+                    return "auto";
+
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(YGValue.Unit));
+            }
+        }
+
+        private void SetValue(SerializedProperty property, YGValue value)
+        {
+            property.FindPropertyRelative(nameof(YGValue.Value)).floatValue = value.Value;
+            property.FindPropertyRelative(nameof(YGValue.Unit)).enumValueIndex = (int) value.Unit;
+        }
+    }
+}