port from perforce

intromat/Intromat/Nodes/Code/VariableReference.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Diagnostics;
+using System.Text;
+using Intromat.Model;
+using Intromat.Model.Compiler;
+using Intromat.Model.Compiler.Error;
+
+namespace Intromat.Nodes.Code
+{
+    public class VariableReference<T> : ITypedExpression<T>
+    {
+        public string? PreviewValue => LocalVariable?.VariableName;
+
+        public ITypedVariableDefinition<T>? LocalVariable { get; set; }
+
+        public void Compile(CompilerContext context, StringBuilder sb)
+        {
+            var localVariable = LocalVariable;
+            Debug.Assert(localVariable != null, nameof(localVariable) + " != null");
+            Debug.Assert(localVariable.VariableName != null, $"{nameof(localVariable)}.{nameof(localVariable.VariableName)} != null");
+
+            if (!context.IsInScope(localVariable))
+                throw new VariableOutOfScopeException(localVariable.VariableName);
+
+            sb.Append(localVariable.VariableName);
+        }
+        public T Evaluate()
+        {
+            throw new NotImplementedException();
+        }
+    }
+}