Flee

CalcEngine/InternalTypes/IdentifierAnalyzer.cs

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+using Flee.Parsing;
+using Flee.PublicTypes;
+
+namespace Flee.CalcEngine.InternalTypes
+{
+    internal class IdentifierAnalyzer : Analyzer
+    {
+
+        private readonly IDictionary<int, string> _myIdentifiers;
+        private int _myMemberExpressionCount;
+
+        private bool _myInFieldPropertyExpression;
+        public IdentifierAnalyzer()
+        {
+            _myIdentifiers = new Dictionary<int, string>();
+        }
+
+        public override Node Exit(Node node)
+        {
+            switch (node.Id)
+            {
+                case (int)ExpressionConstants.IDENTIFIER:
+                    this.ExitIdentifier((Token)node);
+                    break;
+                case (int)ExpressionConstants.FIELD_PROPERTY_EXPRESSION:
+                    this.ExitFieldPropertyExpression();
+                    break;
+            }
+
+            return node;
+        }
+
+        public override void Enter(Node node)
+        {
+            switch (node.Id)
+            {
+                case (int)ExpressionConstants.MEMBER_EXPRESSION:
+                    this.EnterMemberExpression();
+                    break;
+                case (int)ExpressionConstants.FIELD_PROPERTY_EXPRESSION:
+                    this.EnterFieldPropertyExpression();
+                    break;
+            }
+        }
+
+        private void ExitIdentifier(Token node)
+        {
+            if (_myInFieldPropertyExpression == false)
+            {
+                return;
+            }
+
+            if (_myIdentifiers.ContainsKey(_myMemberExpressionCount) == false)
+            {
+                _myIdentifiers.Add(_myMemberExpressionCount, node.Image);
+            }
+        }
+
+        private void EnterMemberExpression()
+        {
+            _myMemberExpressionCount += 1;
+        }
+
+        private void EnterFieldPropertyExpression()
+        {
+            _myInFieldPropertyExpression = true;
+        }
+
+        private void ExitFieldPropertyExpression()
+        {
+            _myInFieldPropertyExpression = false;
+        }
+
+        public override void Reset()
+        {
+            _myIdentifiers.Clear();
+            _myMemberExpressionCount = -1;
+        }
+
+        public ICollection<string> GetIdentifiers(ExpressionContext context)
+        {
+            Dictionary<string, object> dict = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
+            ExpressionImports ei = context.Imports;
+
+            foreach (string identifier in _myIdentifiers.Values)
+            {
+                // Skip names registered as namespaces
+                if (ei.HasNamespace(identifier) == true)
+                {
+                    continue;
+                }
+                else if (context.Variables.ContainsKey(identifier) == true)
+                {
+                    // Identifier is a variable
+                    continue;
+                }
+
+                // Get only the unique values
+                dict[identifier] = null;
+            }
+
+            return dict.Keys;
+        }
+    }
+}