port from perforce

intromat/Intromat/ViewModels/Editors/FloatExpressionEditorViewModel.cs

@@ -0,0 +1,50 @@
+using System;
+using Intromat.Nodes.Code;
+using Intromat.Views.Editors;
+using ReactiveUI;
+using Splat;
+
+namespace Intromat.ViewModels.Editors
+{
+    public class FloatExpressionEditorViewModel : ExpressionEditorBaseViewModel<float, FloatLiteralValue, FloatLiteralModel>
+    {
+        private float _maxValue;
+        private float _minValue;
+
+        static FloatExpressionEditorViewModel()
+        {
+            Locator.CurrentMutable.Register(() => new FloatExpressionEditorView(), typeof(IViewFor<FloatExpressionEditorViewModel>));
+        }
+
+        public FloatExpressionEditorViewModel()
+        {
+            this.WhenAnyValue(vm => vm.Value)
+                .Subscribe(t =>
+                {
+                    var newValue = t!.Evaluate();
+                    if (newValue > MaxValue)
+                    {
+                        var delta = newValue - MinValue;
+                        MaxValue = newValue + delta;
+                    }
+                    else if (newValue < MinValue)
+                    {
+                        var delta = MaxValue - newValue;
+                        MinValue = newValue - delta;
+                    }
+                });
+        }
+
+        public float MinValue
+        {
+            get => _minValue;
+            set => this.RaiseAndSetIfChanged(ref _minValue, value);
+        }
+
+        public float MaxValue
+        {
+            get => _maxValue;
+            set => this.RaiseAndSetIfChanged(ref _maxValue, value);
+        }
+    }
+}