diff --git a/Configuration/GlobalAssemblyInfo.cs b/Configuration/GlobalAssemblyInfo.cs
index f88dbdd4f..76076c356 100644
--- a/Configuration/GlobalAssemblyInfo.cs
+++ b/Configuration/GlobalAssemblyInfo.cs
@@ -14,8 +14,8 @@ internal static class RevisionClass
 {
 	public const string Major = "3";
 	public const string Minor = "10";
-	public const string Build = "2";
-	public const string Revision = "3597";
+	public const string Build = "3";
+	public const string Revision = "3602";
 
         public const string MainVersion = Major + "." + Minor;
 	public const string FullVersion = Major + "." + Minor + "." + Build + "." + Revision;
diff --git a/Configuration/Version.defs b/Configuration/Version.defs
index 8cc06586a..561c69a5d 100644
--- a/Configuration/Version.defs
+++ b/Configuration/Version.defs
@@ -1,4 +1,4 @@
+%COREVERSION%=3
+%REVISION%=3602
 %MINOR%=10
-%REVISION%=3597
-%COREVERSION%=2
 %MAJOR%=3
diff --git a/InstallerSamples/WhatsNew/3_10_3/faststring1.pas b/InstallerSamples/WhatsNew/3_10_3/faststring1.pas
new file mode 100644
index 000000000..868bcb611
--- /dev/null
+++ b/InstallerSamples/WhatsNew/3_10_3/faststring1.pas
@@ -0,0 +1,14 @@
+// 6.0 sec PascalABC.NET vs 11.4 sec Python
+begin
+  var mx := 0;
+  for var n := 4 to 9999 do
+  begin
+    var s: faststring := '4' + '1' * n;
+
+    while ('411' in s) or ('1111' in s) do
+      s.Replace('411', '14', 1).Replace('1111', '1', 1);
+    
+    mx := max(mx, s.ToString.Sum(d -> d.todigit));
+  end;
+  print(mx, Milliseconds / 1000);
+end.
\ No newline at end of file
diff --git a/Release/pabcversion.txt b/Release/pabcversion.txt
index bc7ffd4b8..7e294f09a 100644
--- a/Release/pabcversion.txt
+++ b/Release/pabcversion.txt
@@ -1 +1 @@
-3.10.2.3597
+3.10.3.3602
diff --git a/ReleaseGenerators/PascalABCNET_version.nsh b/ReleaseGenerators/PascalABCNET_version.nsh
index 82ee1e15e..218703934 100644
--- a/ReleaseGenerators/PascalABCNET_version.nsh
+++ b/ReleaseGenerators/PascalABCNET_version.nsh
@@ -1 +1 @@
-!define VERSION '3.10.2.3597'
+!define VERSION '3.10.3.3602'
diff --git a/SyntaxTree/tree/NodesBuilder.cs b/SyntaxTree/tree/NodesBuilder.cs
index b0ba48b55..da3002e5d 100644
--- a/SyntaxTree/tree/NodesBuilder.cs
+++ b/SyntaxTree/tree/NodesBuilder.cs
@@ -5,6 +5,8 @@ using System.Text;
 
 namespace PascalABCCompiler.SyntaxTree
 {
+    // По идее из разных мест сюда всё собрано в три разных хаотичных класса
+
     #region Генерация новых узлов синтаксического дерева
     /// <summary>
     /// Класс для генерации новых узлов синтаксического дерева
@@ -295,11 +297,11 @@ namespace PascalABCCompiler.SyntaxTree
         private static procedure_definition InternalCreateProcedureDefinitionNode(string methName, formal_parameters formalPars, bool classKeyword, statement procBody, SourceContext sc)
         {
             return SyntaxTreeNodesConstructor.CreateProcedureDefinitionNode(new method_name(methName),
-                                                                                                                         formalPars,
-                                                                                                                         false,
-                                                                                                                         classKeyword,
-                                                                                                                         procBody,
-                                                                                                                         sc);
+                formalPars,
+                false,
+                classKeyword,
+                procBody,
+                sc);
         }
 
         public static procedure_definition CreateProcedureDefinitionNode(string methName, formal_parameters formalPars, bool classKeyword, statement procBody, SourceContext sc)
@@ -315,12 +317,12 @@ namespace PascalABCCompiler.SyntaxTree
         private static procedure_definition InternalCreateFunctionDefinitionNode(string methName, formal_parameters formalPars, bool classKeyword, statement procBody, type_definition returnType, SourceContext sc)
         {
             return SyntaxTreeNodesConstructor.CreateFunctionDefinitionNode(new method_name(methName),
-                                                                                                                        formalPars,
-                                                                                                                        false,
-                                                                                                                        classKeyword,
-                                                                                                                        procBody,
-                                                                                                                        returnType,
-                                                                                                                        sc);
+                formalPars,
+                false,
+                classKeyword,
+                procBody,
+                returnType,
+                sc);
         }
 
         public static procedure_definition CreateFunctionDefinitionNode(string methName, formal_parameters formalPars, bool classKeyword, statement procBody, type_definition returnType, SourceContext sc)
@@ -355,10 +357,14 @@ namespace PascalABCCompiler.SyntaxTree
         public static SourceContext BuildGenSC = new SourceContext(0, 777777, 0, 0, 0, 0);
 
         private static int GenIdNum = 0;
-        public static ident GenIdentName()
+        public static string UniqueString()
         {
             GenIdNum++;
-            return new ident("$GenId" + GenIdNum.ToString());
+            return GenIdNum.ToString();
+        }
+        public static ident GenIdentName()
+        {
+            return new ident("$GenId" + UniqueString());
         }
 
         public static type_definition BuildSimpleType(string name)
@@ -420,6 +426,23 @@ namespace PascalABCCompiler.SyntaxTree
             return sl;
         }
 
+        // SSM 25.01.25
+        public static procedure_definition BuildSimpleFunction(string name, List<ident> paramNames, List<type_definition> paramTypes, type_definition returnType, statement procBody, SourceContext sc = null)
+        {
+            var fp = SyntaxTreeBuilder.BuildFormalParameters(paramNames, paramTypes);
+            var fdn = SyntaxTreeNodesConstructor.CreateFunctionDefinitionNode(new method_name(name), fp, false, false, procBody, returnType, sc);
+            return fdn;
+        }
+        public static procedure_definition BuildSimpleFunctionOneParameter(string name, string paramName, type_definition paramType, type_definition returnType, statement procBody, SourceContext sc = null)
+        {
+            var lstNames = new List<ident>();
+            lstNames.Add(new ident(paramName));
+            var lstTypes = new List<type_definition>();
+            lstTypes.Add(paramType);
+            var fp = SyntaxTreeBuilder.BuildFormalParameters(lstNames, lstTypes);
+            var fdn = SyntaxTreeNodesConstructor.CreateFunctionDefinitionNode(new method_name(name), fp, false, false, procBody, returnType, sc);
+            return fdn;
+        }
         public static procedure_definition BuildSimpleConstructor(List<ident> fields, List<ident> formal_names, List<type_definition> types)
         {
             var fp = SyntaxTreeBuilder.BuildFormalParameters(formal_names, types);
diff --git a/TestSuite/CompilationSamples/PABCSystem.pas b/TestSuite/CompilationSamples/PABCSystem.pas
index a544854a4..052651fe7 100644
--- a/TestSuite/CompilationSamples/PABCSystem.pas
+++ b/TestSuite/CompilationSamples/PABCSystem.pas
@@ -105,7 +105,7 @@ type
   
   /// Представляет произвольно большое целое число
   BigInteger = System.Numerics.BigInteger;
-
+  
   /// Представляет дату и время
   DateTime = System.DateTime;
   
@@ -181,6 +181,9 @@ type
   /// Представляет изменяемую строку символов
   StringBuilder = System.Text.StringBuilder;
   
+  /// Представляет строку с эффективным изменением
+  faststring = StringBuilder;
+
   /// Тип кодировки символов  
   Encoding = System.Text.Encoding;
   
@@ -483,7 +486,7 @@ type
   end;}
   
 type
-  NewSetEmpty = class;
+  EmptyCollection = class;
   
   /// Тип встроенного множества
   NewSet<T> = record(IEnumerable<T>)
@@ -558,66 +561,77 @@ type
     begin 
       Result._hs := new HashSet<T>(a);
     end;
-
-    static function operator implicit(ns: NewSetEmpty): NewSet<T>; begin end;
     static function operator:=(var s: NewSet<T>; st: NewSet<T>): NewSet<T>; // Эту функцию обязательно здесь определять
     begin
       s._hs := new HashSet<T>(st.hs);
     end;
+    static function operator implicit(ns: EmptyCollection): NewSet<T>; begin end;
   end;
   
-  NewSetEmpty = class 
+  EmptyCollection = class 
   public
-    static function operator=<T>(s1: NewSet<T>; s2: NewSetEmpty): boolean := s1.Count = 0;
-    static function operator=<T>(s2: NewSetEmpty; s1: NewSet<T>): boolean := s1.Count = 0;
-    static function operator<><T>(s1: NewSet<T>; s2: NewSetEmpty): boolean := not (s1 = s2);
-    static function operator<><T>(s2: NewSetEmpty; s1: NewSet<T>): boolean := not (s1 = s2);
-    static function operator><T>(s1: NewSet<T>; s2: NewSetEmpty): boolean := s1.Count > 0;
-    static function operator><T>(s2: NewSetEmpty; s1: NewSet<T>): boolean := False;
-    static function operator<<T>(s1: NewSet<T>; s2: NewSetEmpty): boolean := False;
-    static function operator<<T>(s2: NewSetEmpty; s1: NewSet<T>): boolean := s1.Count > 0;
-    static function operator>=<T>(s1: NewSet<T>; s2: NewSetEmpty): boolean := s1.Count >= 0;
-    static function operator>=<T>(s2: NewSetEmpty; s1: NewSet<T>): boolean := False;
-    static function operator<=<T>(s1: NewSet<T>; s2: NewSetEmpty): boolean := False;
-    static function operator<=<T>(s2: NewSetEmpty; s1: NewSet<T>): boolean := s1.Count >= 0;
+    static function operator=<T>(s1: NewSet<T>; s2: EmptyCollection): boolean := s1.Count = 0;
+    static function operator=<T>(s2: EmptyCollection; s1: NewSet<T>): boolean := s1.Count = 0;
+    static function operator<><T>(s1: NewSet<T>; s2: EmptyCollection): boolean := not (s1 = s2);
+    static function operator<><T>(s2: EmptyCollection; s1: NewSet<T>): boolean := not (s1 = s2);
+    static function operator><T>(s1: NewSet<T>; s2: EmptyCollection): boolean := s1.Count > 0;
+    static function operator><T>(s2: EmptyCollection; s1: NewSet<T>): boolean := False;
+    static function operator<<T>(s1: NewSet<T>; s2: EmptyCollection): boolean := False;
+    static function operator<<T>(s2: EmptyCollection; s1: NewSet<T>): boolean := s1.Count > 0;
+    static function operator>=<T>(s1: NewSet<T>; s2: EmptyCollection): boolean := s1.Count >= 0;
+    static function operator>=<T>(s2: EmptyCollection; s1: NewSet<T>): boolean := False;
+    static function operator<=<T>(s1: NewSet<T>; s2: EmptyCollection): boolean := False;
+    static function operator<=<T>(s2: EmptyCollection; s1: NewSet<T>): boolean := s1.Count >= 0;
     // ToDo: определить то же для массивов на будущее
     
-    static function operator+(first, second: NewSetEmpty): NewSetEmpty := new NewSetEmpty;
-    static function operator-(first, second: NewSetEmpty): NewSetEmpty := new NewSetEmpty;
-    static function operator*(first, second: NewSetEmpty): NewSetEmpty := new NewSetEmpty;
-    static function operator+<T>(first: NewSetEmpty; second: array of T): NewSet<T>;
+    static function operator+(first, second: EmptyCollection): EmptyCollection := new EmptyCollection;
+    static function operator-(first, second: EmptyCollection): EmptyCollection := new EmptyCollection;
+    static function operator*(first, second: EmptyCollection): EmptyCollection := new EmptyCollection;
+    static function operator+<T>(first: EmptyCollection; second: array of T): NewSet<T>;
     begin 
       Result.hs.UnionWith(second);
     end;
-    static function operator+<T>(first: array of T; second: NewSetEmpty): NewSet<T>;
+    static function operator+<T>(first: array of T; second: EmptyCollection): NewSet<T>;
     begin 
       Result.hs.UnionWith(first);
     end;
-    static function operator+<T>(first: NewSet<T>; second: NewSetEmpty): NewSet<T> := first;
-    static function operator+<T>(first: NewSetEmpty; second: NewSet<T>): NewSet<T> := second;
-    static function operator*<T>(first: NewSet<T>; second: NewSetEmpty): NewSet<T>; begin end;
-    static function operator*<T>(first: NewSetEmpty; second: NewSet<T>): NewSet<T>; begin end;
-    static function operator-<T>(first: NewSet<T>; second: NewSetEmpty): NewSet<T> := first;
-    static function operator-<T>(first: NewSetEmpty; second: NewSet<T>): NewSet<T>; begin end;
+    static function operator+<T>(first: NewSet<T>; second: EmptyCollection): NewSet<T> := first;
+    static function operator+<T>(first: EmptyCollection; second: NewSet<T>): NewSet<T> := second;
+    static function operator*<T>(first: NewSet<T>; second: EmptyCollection): NewSet<T>; begin end;
+    static function operator*<T>(first: EmptyCollection; second: NewSet<T>): NewSet<T>; begin end;
+    static function operator-<T>(first: NewSet<T>; second: EmptyCollection): NewSet<T> := first;
+    static function operator-<T>(first: EmptyCollection; second: NewSet<T>): NewSet<T>; begin end;
     
-    static function operator*<T>(first: NewSetEmpty; second: array of T): NewSet<T>; begin end;
-    static function operator*<T>(first: array of T; second: NewSetEmpty): NewSet<T>; begin end;
-    static function operator-<T>(first: NewSetEmpty; second: array of T): NewSet<T>; begin end;
-    static function operator-<T>(first: array of T; second: NewSetEmpty): NewSet<T>;
+    static function operator*<T>(first: EmptyCollection; second: array of T): NewSet<T>; begin end;
+    static function operator*<T>(first: array of T; second: EmptyCollection): NewSet<T>; begin end;
+    static function operator-<T>(first: EmptyCollection; second: array of T): NewSet<T>; begin end;
+    static function operator-<T>(first: array of T; second: EmptyCollection): NewSet<T>;
     begin 
       Result.hs.UnionWith(first);
     end;
     function ToString: string; override := '{}';
     function ToSet<T>(): NewSet<T>; begin end; 
 
-    static function operator implicit<T>(Self: NewSetEmpty): array of T; 
+    static function operator implicit<T>(Self: EmptyCollection): array of T; 
     begin
-      Result := new T[0];
+      Result := new T[0]//System.Array.Empty&<T>;
     end;
-    static function operator implicit<T>(Self: NewSetEmpty): HashSet<T>; 
+    static function operator implicit<T>(Self: EmptyCollection): HashSet<T>; 
     begin
       Result := new HashSet<T>;
     end;
+    static function operator implicit<T>(Self: EmptyCollection): SortedSet<T>; 
+    begin
+      Result := new SortedSet<T>;
+    end;
+    static function operator implicit<T>(Self: EmptyCollection): List<T>; 
+    begin
+      Result := new List<T>;
+    end;
+    static function operator implicit<K,V>(Self: EmptyCollection): Dictionary<K,V>; 
+    begin
+      Result := new Dictionary<K,V>;
+    end;
   end;  
   
 type
@@ -667,7 +681,7 @@ type
   end;
 
 /// Значение пустого множества  
-function EmptySet: NewSetEmpty;
+function EmptySet: EmptyCollection;
 
 /// Генератор множества
 function __NewSetCreatorInternal<T>(params a: array of T): NewSet<T>;
@@ -14689,6 +14703,81 @@ begin
     &to.IndexValue := Self.Count - &to.IndexValue + 1;
   Result := SystemSliceStringImplQuestion(Self, situation, from.IndexValue, &to.IndexValue, step, 0);
 end;
+
+//--------------------------------------------
+//>>     Методы расширения типа faststring (StringBuilder) # Extension methods for faststring (StringBuilder)
+//--------------------------------------------
+/// Возвращает индекс вхождения подстроки в быструю строку  
+function IndexOf(Self: faststring; subs: string; from: integer := 0): integer; extensionmethod;
+begin
+  var lens := Self.Length;
+  var lens1 := subs.Length;
+  
+  if (from < 0) or (lens1 > lens - from) then
+  begin
+    Result := -1;
+    exit;
+  end;
+  
+  if lens1 = 0 then 
+  begin
+    Result := from; 
+    exit; 
+  end;
+  
+  for var i := from to lens - lens1 do
+  begin
+    var found := True;
+    for var j := 0 to lens1 - 1 do
+    begin
+      if Self[i + j] <> subs[j + 1] then
+      begin
+        found := False;
+        break;
+      end;
+    end;
+    
+    if found then 
+    begin
+      Result := i; 
+      exit; 
+    end;
+  end;  
+  
+  Result := -1; 
+end;
+
+/// Преобразует быструю строку в последовательность символов
+function ToSequence(Self: faststring): sequence of char; extensionmethod;
+begin
+  for var i:=0 to Self.Length - 1 do
+    yield Self[i];
+end;
+
+function operator in(subs: string; s: faststring): boolean; extensionmethod;
+begin
+  Result := s.IndexOf(subs) <> -1;
+end;
+
+/// Замещает n вхождений указанной строки на другую строку (все при n = 0)
+function Replace(Self: faststring; OldValue, NewValue: string; n: integer): faststring; extensionmethod;
+begin
+  if n = 0 then
+    Self.Replace(OldValue, NewValue)   // стандартный метод StringBuilder
+  else begin
+    var from := 0;
+    loop n do
+    begin
+      var index := Self.IndexOf(OldValue, from);
+      if index = -1 then exit;
+      Self.Remove(index, OldValue.Length);
+      Self.Insert(index, NewValue);
+      from := index + NewValue.Length;
+    end;
+  end;
+  Result := Self;
+end;
+
 //--------------------------------------------
 //>>     Методы расширения типа Func # Extension methods for Func
 //--------------------------------------------
@@ -15415,7 +15504,7 @@ end;}
 
 // Присваивание реализовано в PABCExtensions. Здесь не работает
 
-var _emptyset: NewSetEmpty := new NewSetEmpty;
+var _emptyset: EmptyCollection := new EmptyCollection;
 
 type 
   SetCreatorFunctionAttribute = class(Attribute)
diff --git a/TreeConverter/TreeConversion/convertion_data_and_alghoritms.cs b/TreeConverter/TreeConversion/convertion_data_and_alghoritms.cs
index d38a59549..af9f6eb3c 100644
--- a/TreeConverter/TreeConversion/convertion_data_and_alghoritms.cs
+++ b/TreeConverter/TreeConversion/convertion_data_and_alghoritms.cs
@@ -6,7 +6,9 @@ using System.Collections.Generic;
 using System.Linq;
 
 using PascalABCCompiler.SemanticTree;
+using PascalABCCompiler.SyntaxTree;
 using PascalABCCompiler.TreeRealization;
+using static PascalABCCompiler.SyntaxTree.SyntaxTreeBuilder;
 
 namespace PascalABCCompiler.TreeConverter
 {
@@ -1208,36 +1210,56 @@ namespace PascalABCCompiler.TreeConverter
 						else
 						{
                             // SSM 20/01/25 - Tuple<int,int> -> Tuple<double,double>
-                            /*if (formal_param_type.original_generic != null 
+                            if (formal_param_type.original_generic != null 
                                 && formal_param_type.original_generic.BaseFullName.StartsWith("System.Tuple`")
                                 && factparams[i].type.original_generic != null
                                 && factparams[i].type.original_generic.BaseFullName.StartsWith("System.Tuple`")
                                 && formal_param_type.instance_params.Count == factparams[i].type.instance_params.Count
-                                && factparams[i] is IFunctionCallNode fpf 
-                                && fpf.function.name == "Create")
+                                //&& factparams[i] is IFunctionCallNode fpf 
+                                //&& fpf.function.name == "Create"
+                                )
                             {
-                                expressions_list el = null;
-                                function_node fn = null;
-                                if (fpf is common_static_method_call fpf1) { 
-                                    el = fpf1.parameters;
-                                    fn = fpf1.function_node;
-                                }
-                                else if (fpf is compiled_static_method_call fpf2) { 
-                                    el = fpf2.parameters;
-                                    fn = fpf2.function_node;
-                                }
-                                var ccc = syntax_tree_visitor.create_constructor_call(formal_param_type,
-                                     el, factparams[i].location);
+                                syntax_tree_visitor.contextChanger.SaveContextAndUpToGlobalLevel();
+                                var sl = new statement_list();
+                                var rettype = new semantic_type_node(formal_param_type);
+
+                                //expressions_list parameters = null;
+                                //if (fpf is common_static_method_call fpf1) {
+                                //    parameters = fpf1.parameters;
+                                //}
+                                //else if (fpf is compiled_static_method_call fpf2) {
+                                //    parameters = fpf2.parameters;
+                                //}
+
+                                var el = new expression_list();
+                                for (int ii = 1; ii <= formal_param_type.instance_params.Count; ii++)
+                                    el.Add(new dot_node(new ident("x"), new ident("Item" + ii.ToString(),
+                                        factparams[i].location)));
+                                        //parameters[ii-1].location)));
+                                SyntaxTree.expression ex = new SyntaxTree.new_expr(rettype,el);
+                                sl.Add(new SyntaxTree.assign("Result", ex));
+                                // Определим функцию преобразования на внешнем уровне
+                                var fun = BuildSimpleFunctionOneParameter("_conv" + UniqueString(), "x",
+                                    new SyntaxTree.semantic_type_node(factparams[i].type),
+                                    rettype,
+                                    sl
+                                    );
+                                // Теперь ее надо обойти
+                                syntax_tree_visitor.ProcessNode(fun);
+                                // Теперь до нее доберемся
+                                var fn = syntax_tree_visitor.context.last_created_function.sym_info as function_node;
+                                syntax_tree_visitor.contextChanger.RestoreCurrentContext();
+                                //var ccc = syntax_tree_visitor.create_constructor_call(formal_param_type,
+                                //     el, factparams[i].location);
                                 //factparams[i] = ccc;
                                 possible_type_convertions ptci = new possible_type_convertions();
-                                var ttttt = (ccc as compiled_constructor_call).function_node;
-                                ptci.first = new type_conversion(ttttt);
+                                ptci.first = new type_conversion(fn);
                                 ptci.second = null;
                                 ptci.from = factparams[i].type;
                                 ptci.to = formal_param_type;
                                 tc.AddElement(ptci);
                                 return tc;
-                            }*/
+                            }
 
                             //issue #2161 - SSM 12.03.2020
                             //issue #348
diff --git a/TreeConverter/TreeConversion/syntax_tree_visitor.cs b/TreeConverter/TreeConversion/syntax_tree_visitor.cs
index d0dc5755a..608c32a3f 100644
--- a/TreeConverter/TreeConversion/syntax_tree_visitor.cs
+++ b/TreeConverter/TreeConversion/syntax_tree_visitor.cs
@@ -15460,7 +15460,7 @@ namespace PascalABCCompiler.TreeConverter
             {
                 // Отдельно для пустого множества 
                 common_namespace_function_call cnfc = expr as common_namespace_function_call;
-                if (cnfc.type.name == "NewSetEmpty")
+                if (cnfc.type.name == "EmptyCollection")
                 {
                     constant = new common_namespace_function_call_as_constant(expr as common_namespace_function_call, loc);
                     return constant;
@@ -15475,7 +15475,7 @@ namespace PascalABCCompiler.TreeConverter
                 return constant;
             }
             else if (expr is common_namespace_function_call_as_constant cnfcac
-                && cnfcac.type.name == "NewSetEmpty")
+                && cnfcac.type.name == "EmptyCollection")
             {
                 expr = create_constructor_call(tn, new expressions_list(), loc);
                 constant = new common_constructor_call_as_constant(expr as common_constructor_call, loc);
diff --git a/bin/Highlighting/PascalABCNET.xshd b/bin/Highlighting/PascalABCNET.xshd
index 9ac52ebd1..071df0bc2 100644
--- a/bin/Highlighting/PascalABCNET.xshd
+++ b/bin/Highlighting/PascalABCNET.xshd
@@ -235,6 +235,7 @@
 		<Key word = "word" />
 		<Key word = "integer" />
 		<Key word = "BigInteger" />
+		<Key word = "Complex" />
 		<Key word = "longword" />
 		<Key word = "uint64" />
 		<Key word = "cardinal" />
@@ -242,6 +243,7 @@
 		<Key word = "single" />
 		<Key word = "longint" />
 		<Key word = "string" />
+		<Key word = "faststring" />
 		<Key word = "char" />
 		<Key word = "real" />
 		<Key word = "double" />
diff --git a/bin/Lib/PABCSystem.pas b/bin/Lib/PABCSystem.pas
index a544854a4..052651fe7 100644
--- a/bin/Lib/PABCSystem.pas
+++ b/bin/Lib/PABCSystem.pas
@@ -105,7 +105,7 @@ type
   
   /// Представляет произвольно большое целое число
   BigInteger = System.Numerics.BigInteger;
-
+  
   /// Представляет дату и время
   DateTime = System.DateTime;
   
@@ -181,6 +181,9 @@ type
   /// Представляет изменяемую строку символов
   StringBuilder = System.Text.StringBuilder;
   
+  /// Представляет строку с эффективным изменением
+  faststring = StringBuilder;
+
   /// Тип кодировки символов  
   Encoding = System.Text.Encoding;
   
@@ -483,7 +486,7 @@ type
   end;}
   
 type
-  NewSetEmpty = class;
+  EmptyCollection = class;
   
   /// Тип встроенного множества
   NewSet<T> = record(IEnumerable<T>)
@@ -558,66 +561,77 @@ type
     begin 
       Result._hs := new HashSet<T>(a);
     end;
-
-    static function operator implicit(ns: NewSetEmpty): NewSet<T>; begin end;
     static function operator:=(var s: NewSet<T>; st: NewSet<T>): NewSet<T>; // Эту функцию обязательно здесь определять
     begin
       s._hs := new HashSet<T>(st.hs);
     end;
+    static function operator implicit(ns: EmptyCollection): NewSet<T>; begin end;
   end;
   
-  NewSetEmpty = class 
+  EmptyCollection = class 
   public
-    static function operator=<T>(s1: NewSet<T>; s2: NewSetEmpty): boolean := s1.Count = 0;
-    static function operator=<T>(s2: NewSetEmpty; s1: NewSet<T>): boolean := s1.Count = 0;
-    static function operator<><T>(s1: NewSet<T>; s2: NewSetEmpty): boolean := not (s1 = s2);
-    static function operator<><T>(s2: NewSetEmpty; s1: NewSet<T>): boolean := not (s1 = s2);
-    static function operator><T>(s1: NewSet<T>; s2: NewSetEmpty): boolean := s1.Count > 0;
-    static function operator><T>(s2: NewSetEmpty; s1: NewSet<T>): boolean := False;
-    static function operator<<T>(s1: NewSet<T>; s2: NewSetEmpty): boolean := False;
-    static function operator<<T>(s2: NewSetEmpty; s1: NewSet<T>): boolean := s1.Count > 0;
-    static function operator>=<T>(s1: NewSet<T>; s2: NewSetEmpty): boolean := s1.Count >= 0;
-    static function operator>=<T>(s2: NewSetEmpty; s1: NewSet<T>): boolean := False;
-    static function operator<=<T>(s1: NewSet<T>; s2: NewSetEmpty): boolean := False;
-    static function operator<=<T>(s2: NewSetEmpty; s1: NewSet<T>): boolean := s1.Count >= 0;
+    static function operator=<T>(s1: NewSet<T>; s2: EmptyCollection): boolean := s1.Count = 0;
+    static function operator=<T>(s2: EmptyCollection; s1: NewSet<T>): boolean := s1.Count = 0;
+    static function operator<><T>(s1: NewSet<T>; s2: EmptyCollection): boolean := not (s1 = s2);
+    static function operator<><T>(s2: EmptyCollection; s1: NewSet<T>): boolean := not (s1 = s2);
+    static function operator><T>(s1: NewSet<T>; s2: EmptyCollection): boolean := s1.Count > 0;
+    static function operator><T>(s2: EmptyCollection; s1: NewSet<T>): boolean := False;
+    static function operator<<T>(s1: NewSet<T>; s2: EmptyCollection): boolean := False;
+    static function operator<<T>(s2: EmptyCollection; s1: NewSet<T>): boolean := s1.Count > 0;
+    static function operator>=<T>(s1: NewSet<T>; s2: EmptyCollection): boolean := s1.Count >= 0;
+    static function operator>=<T>(s2: EmptyCollection; s1: NewSet<T>): boolean := False;
+    static function operator<=<T>(s1: NewSet<T>; s2: EmptyCollection): boolean := False;
+    static function operator<=<T>(s2: EmptyCollection; s1: NewSet<T>): boolean := s1.Count >= 0;
     // ToDo: определить то же для массивов на будущее
     
-    static function operator+(first, second: NewSetEmpty): NewSetEmpty := new NewSetEmpty;
-    static function operator-(first, second: NewSetEmpty): NewSetEmpty := new NewSetEmpty;
-    static function operator*(first, second: NewSetEmpty): NewSetEmpty := new NewSetEmpty;
-    static function operator+<T>(first: NewSetEmpty; second: array of T): NewSet<T>;
+    static function operator+(first, second: EmptyCollection): EmptyCollection := new EmptyCollection;
+    static function operator-(first, second: EmptyCollection): EmptyCollection := new EmptyCollection;
+    static function operator*(first, second: EmptyCollection): EmptyCollection := new EmptyCollection;
+    static function operator+<T>(first: EmptyCollection; second: array of T): NewSet<T>;
     begin 
       Result.hs.UnionWith(second);
     end;
-    static function operator+<T>(first: array of T; second: NewSetEmpty): NewSet<T>;
+    static function operator+<T>(first: array of T; second: EmptyCollection): NewSet<T>;
     begin 
       Result.hs.UnionWith(first);
     end;
-    static function operator+<T>(first: NewSet<T>; second: NewSetEmpty): NewSet<T> := first;
-    static function operator+<T>(first: NewSetEmpty; second: NewSet<T>): NewSet<T> := second;
-    static function operator*<T>(first: NewSet<T>; second: NewSetEmpty): NewSet<T>; begin end;
-    static function operator*<T>(first: NewSetEmpty; second: NewSet<T>): NewSet<T>; begin end;
-    static function operator-<T>(first: NewSet<T>; second: NewSetEmpty): NewSet<T> := first;
-    static function operator-<T>(first: NewSetEmpty; second: NewSet<T>): NewSet<T>; begin end;
+    static function operator+<T>(first: NewSet<T>; second: EmptyCollection): NewSet<T> := first;
+    static function operator+<T>(first: EmptyCollection; second: NewSet<T>): NewSet<T> := second;
+    static function operator*<T>(first: NewSet<T>; second: EmptyCollection): NewSet<T>; begin end;
+    static function operator*<T>(first: EmptyCollection; second: NewSet<T>): NewSet<T>; begin end;
+    static function operator-<T>(first: NewSet<T>; second: EmptyCollection): NewSet<T> := first;
+    static function operator-<T>(first: EmptyCollection; second: NewSet<T>): NewSet<T>; begin end;
     
-    static function operator*<T>(first: NewSetEmpty; second: array of T): NewSet<T>; begin end;
-    static function operator*<T>(first: array of T; second: NewSetEmpty): NewSet<T>; begin end;
-    static function operator-<T>(first: NewSetEmpty; second: array of T): NewSet<T>; begin end;
-    static function operator-<T>(first: array of T; second: NewSetEmpty): NewSet<T>;
+    static function operator*<T>(first: EmptyCollection; second: array of T): NewSet<T>; begin end;
+    static function operator*<T>(first: array of T; second: EmptyCollection): NewSet<T>; begin end;
+    static function operator-<T>(first: EmptyCollection; second: array of T): NewSet<T>; begin end;
+    static function operator-<T>(first: array of T; second: EmptyCollection): NewSet<T>;
     begin 
       Result.hs.UnionWith(first);
     end;
     function ToString: string; override := '{}';
     function ToSet<T>(): NewSet<T>; begin end; 
 
-    static function operator implicit<T>(Self: NewSetEmpty): array of T; 
+    static function operator implicit<T>(Self: EmptyCollection): array of T; 
     begin
-      Result := new T[0];
+      Result := new T[0]//System.Array.Empty&<T>;
     end;
-    static function operator implicit<T>(Self: NewSetEmpty): HashSet<T>; 
+    static function operator implicit<T>(Self: EmptyCollection): HashSet<T>; 
     begin
       Result := new HashSet<T>;
     end;
+    static function operator implicit<T>(Self: EmptyCollection): SortedSet<T>; 
+    begin
+      Result := new SortedSet<T>;
+    end;
+    static function operator implicit<T>(Self: EmptyCollection): List<T>; 
+    begin
+      Result := new List<T>;
+    end;
+    static function operator implicit<K,V>(Self: EmptyCollection): Dictionary<K,V>; 
+    begin
+      Result := new Dictionary<K,V>;
+    end;
   end;  
   
 type
@@ -667,7 +681,7 @@ type
   end;
 
 /// Значение пустого множества  
-function EmptySet: NewSetEmpty;
+function EmptySet: EmptyCollection;
 
 /// Генератор множества
 function __NewSetCreatorInternal<T>(params a: array of T): NewSet<T>;
@@ -14689,6 +14703,81 @@ begin
     &to.IndexValue := Self.Count - &to.IndexValue + 1;
   Result := SystemSliceStringImplQuestion(Self, situation, from.IndexValue, &to.IndexValue, step, 0);
 end;
+
+//--------------------------------------------
+//>>     Методы расширения типа faststring (StringBuilder) # Extension methods for faststring (StringBuilder)
+//--------------------------------------------
+/// Возвращает индекс вхождения подстроки в быструю строку  
+function IndexOf(Self: faststring; subs: string; from: integer := 0): integer; extensionmethod;
+begin
+  var lens := Self.Length;
+  var lens1 := subs.Length;
+  
+  if (from < 0) or (lens1 > lens - from) then
+  begin
+    Result := -1;
+    exit;
+  end;
+  
+  if lens1 = 0 then 
+  begin
+    Result := from; 
+    exit; 
+  end;
+  
+  for var i := from to lens - lens1 do
+  begin
+    var found := True;
+    for var j := 0 to lens1 - 1 do
+    begin
+      if Self[i + j] <> subs[j + 1] then
+      begin
+        found := False;
+        break;
+      end;
+    end;
+    
+    if found then 
+    begin
+      Result := i; 
+      exit; 
+    end;
+  end;  
+  
+  Result := -1; 
+end;
+
+/// Преобразует быструю строку в последовательность символов
+function ToSequence(Self: faststring): sequence of char; extensionmethod;
+begin
+  for var i:=0 to Self.Length - 1 do
+    yield Self[i];
+end;
+
+function operator in(subs: string; s: faststring): boolean; extensionmethod;
+begin
+  Result := s.IndexOf(subs) <> -1;
+end;
+
+/// Замещает n вхождений указанной строки на другую строку (все при n = 0)
+function Replace(Self: faststring; OldValue, NewValue: string; n: integer): faststring; extensionmethod;
+begin
+  if n = 0 then
+    Self.Replace(OldValue, NewValue)   // стандартный метод StringBuilder
+  else begin
+    var from := 0;
+    loop n do
+    begin
+      var index := Self.IndexOf(OldValue, from);
+      if index = -1 then exit;
+      Self.Remove(index, OldValue.Length);
+      Self.Insert(index, NewValue);
+      from := index + NewValue.Length;
+    end;
+  end;
+  Result := Self;
+end;
+
 //--------------------------------------------
 //>>     Методы расширения типа Func # Extension methods for Func
 //--------------------------------------------
@@ -15415,7 +15504,7 @@ end;}
 
 // Присваивание реализовано в PABCExtensions. Здесь не работает
 
-var _emptyset: NewSetEmpty := new NewSetEmpty;
+var _emptyset: EmptyCollection := new EmptyCollection;
 
 type 
   SetCreatorFunctionAttribute = class(Attribute)