rewrite of SearchExpression

ParadoxSaveParser.Lib/SaveParserEU4.cs

@@ -12,17 +12,16 @@ public class SaveParserEU4
 {
     protected Stream _saveFile;
     private BufferedEnumerator<Token> _tokens;
-    private SearchExpression _query;
-    private int _currentDepth;
+    private ISearchExpression? _searchExprCurrent;
     
     /// <param name="savefile">Uncompressed stream of <c>gamestate</c> file which can be extracted from save archive</param>
     /// <param name="query">Parsing whole save takes 10 seconds on mid pc and takes 1GB of RAM,
     /// so you should specify what exactly you want to get from save file</param>
-    public SaveParserEU4(Stream savefile, SearchExpression query)
+    public SaveParserEU4(Stream savefile, ISearchExpression? query)
     {
         _tokens = new BufferedEnumerator<Token>(LexTextSave(), 5);
         _saveFile = savefile;
-        _query = query;
+        _searchExprCurrent = query;
     }
 
     protected enum TokenType : byte
@@ -199,9 +198,7 @@ public class SaveParserEU4
                     return l;
                 return tok.value;
             case TokenType.BracketOpen:
-                _currentDepth++;
                 var obj = ParseListOrDict();
-                _currentDepth--;
                 return obj;
             case TokenType.BracketClose:
                 return null;
@@ -307,16 +304,21 @@ public class SaveParserEU4
             // Example: `map_area_data {` instead of `map_area_data = {`
             else if (tok.type != TokenType.BracketOpen)
                 throw new UnexpectedTokenException(tok);
-            
-            if (!_query.DoesMatch(new SearchArgs(key, _currentDepth, localIndex)))
+
+            ISearchExpression? searchExprNext = null;
+            if (_searchExprCurrent != null 
+                && !_searchExprCurrent.DoesMatch(new SearchArgs(key, localIndex), out searchExprNext))
             {
                 SkipValue();
                 continue;
             }
-            
+
+            var searExpressionPrevious = _searchExprCurrent;
+            _searchExprCurrent = searchExprNext;
             object? value = ParseValue();
             if (value is null)
                 throw new UnexpectedTokenException(_tokens.Current.Value);
+            _searchExprCurrent = searExpressionPrevious;
             
             if(!dict.TryGetValue(key, out List<object>? list))
             {