port from perforce

intromat/Intromat/Model/Compiler/CompilerContext.cs

@@ -0,0 +1,49 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Intromat.Model.Compiler
+{
+    public class ScopeDefinition
+    {
+        public ScopeDefinition(string identifier)
+        {
+            Identifier = identifier;
+        }
+
+        public string Identifier { get; }
+
+        public List<IVariableDefinition> Variables { get; } = new();
+    }
+
+    public class CompilerContext
+    {
+        public Stack<ScopeDefinition> VariablesScopesStack { get; } = new();
+
+        public string FindFreeVariableName()
+        {
+            return "v" + VariablesScopesStack.SelectMany(s => s.Variables).Count();
+        }
+
+        public void AddVariableToCurrentScope(IVariableDefinition variable)
+        {
+            VariablesScopesStack.Peek().Variables.Add(variable);
+        }
+
+        public void EnterNewScope(string scopeIdentifier)
+        {
+            VariablesScopesStack.Push(new ScopeDefinition(scopeIdentifier));
+        }
+
+        public void LeaveScope()
+        {
+            VariablesScopesStack.Pop();
+        }
+
+        public bool IsInScope(IVariableDefinition variable)
+        {
+            if (variable == null) return false;
+
+            return VariablesScopesStack.Any(s => s.Variables.Contains(variable));
+        }
+    }
+}