New binding mechanism: Expression tracking

src/Library/TerminalUI/ExpressionTrackers/ParameterTracker.cs

@@ -0,0 +1,31 @@
+using System.Linq.Expressions;
+
+namespace TerminalUI.ExpressionTrackers;
+
+public sealed class ParameterTracker : ExpressionTrackerBase
+{
+    private readonly ExpressionParameterTrackerCollection _trackerCollection;
+    private readonly string _parameterName;
+
+    public ParameterTracker(
+        ParameterExpression parameterExpression, 
+        ExpressionParameterTrackerCollection trackerCollection,
+        string parameterName)
+    {
+        _trackerCollection = trackerCollection;
+        _parameterName = parameterName;
+        
+        trackerCollection.ValueChanged += TrackerCollectionOnValueChanged;
+        
+        UpdateValueAndChangeTrackers();
+    }
+
+    private void TrackerCollectionOnValueChanged(string parameterName, object? newValue) 
+        => UpdateValueAndChangeTrackers();
+
+    protected override object? ComputeValue()
+    {
+        _trackerCollection.Values.TryGetValue(_parameterName, out var v);
+        return v;
+    }
+}