Added HigherOrder.Map<T1,T2> with some overloads

samples/higher_order_functions/MainFormU.dfm

@@ -47,7 +47,7 @@ object MainForm: TMainForm
   object btnMapAddStars: TButton
     Left = 8
     Top = 27
-    Width = 95
+    Width = 74
     Height = 30
     Caption = 'Add Stars'
     TabOrder = 0
@@ -61,7 +61,6 @@ object MainForm: TMainForm
     Anchors = [akLeft, akTop, akBottom]
     ItemHeight = 13
     TabOrder = 1
-    ExplicitHeight = 219
   end
   object btnFilterBetween: TButton
     Left = 380
@@ -81,7 +80,6 @@ object MainForm: TMainForm
     Anchors = [akLeft, akTop, akBottom]
     ItemHeight = 13
     TabOrder = 3
-    ExplicitHeight = 219
   end
   object btnReduceSum: TButton
     Left = 194
@@ -100,7 +98,6 @@ object MainForm: TMainForm
     Anchors = [akLeft, akTop, akBottom]
     ItemHeight = 13
     TabOrder = 5
-    ExplicitHeight = 219
   end
   object btnReduceMin: TButton
     Left = 194
@@ -152,7 +149,7 @@ object MainForm: TMainForm
   object btnMapCapitalize: TButton
     Left = 8
     Top = 63
-    Width = 95
+    Width = 74
     Height = 30
     Caption = 'Capitalize'
     TabOrder = 11
@@ -175,7 +172,6 @@ object MainForm: TMainForm
     Anchors = [akLeft, akTop, akBottom]
     ItemHeight = 13
     TabOrder = 13
-    ExplicitHeight = 219
   end
   object btnForEachWithException: TButton
     Left = 566
@@ -186,4 +182,22 @@ object MainForm: TMainForm
     TabOrder = 14
     OnClick = btnForEachWithExceptionClick
   end
+  object btnMap2: TButton
+    Left = 88
+    Top = 27
+    Width = 100
+    Height = 30
+    Caption = 'Map Enumerable'
+    TabOrder = 15
+    OnClick = btnMap2Click
+  end
+  object btnMap2Array: TButton
+    Left = 88
+    Top = 63
+    Width = 100
+    Height = 30
+    Caption = 'Map Array'
+    TabOrder = 16
+    OnClick = btnMap2ArrayClick
+  end
 end

samples/higher_order_functions/MainFormU.pas

@@ -51,6 +51,8 @@ type
     btnJustLoop: TButton;
     lbForEach: TListBox;
     btnForEachWithException: TButton;
+    btnMap2: TButton;
+    btnMap2Array: TButton;
     procedure btnMapAddStarsClick(Sender: TObject);
     procedure btnReduceSumClick(Sender: TObject);
     procedure btnFilterBetwenClick(Sender: TObject);
@@ -62,6 +64,8 @@ type
     procedure btnMapCapitalizeClick(Sender: TObject);
     procedure btnJustLoopClick(Sender: TObject);
     procedure btnForEachWithExceptionClick(Sender: TObject);
+    procedure btnMap2Click(Sender: TObject);
+    procedure btnMap2ArrayClick(Sender: TObject);
   private
     procedure FillList(Data: TArray<String>; AStrings: TStrings); overload;
     procedure FillList(Data: TArray<Integer>; AStrings: TStrings); overload;
@@ -74,6 +78,9 @@ var
 
 implementation
 
+uses
+  System.Generics.Collections;
+
 {$R *.dfm}
 
 
@@ -170,6 +177,57 @@ begin
     end);
 end;
 
+procedure TMainForm.btnMap2ArrayClick(Sender: TObject);
+begin
+  lbMap.Clear;
+  var lInput: TArray<Integer>;
+
+  SetLength(lInput, 10);
+  for var I := 1 to Length(lInput) do
+  begin
+    lInput[I-1] := I * 10;
+  end;
+
+  var lListOfStr := HigherOrder.Map<Integer, String>(
+    lInput, function(const Item: Integer): String
+            begin
+              Result := '**' + Item.ToString;
+            end);
+  try
+    lbMap.Items.AddStrings(lListOfStr.ToArray);
+  finally
+    lListOfStr.Free;
+  end;
+end;
+
+procedure TMainForm.btnMap2Click(Sender: TObject);
+begin
+  lbMap.Clear;
+  var lList := TList<TButton>.Create;
+  try
+    for var lControl in Self.GetControls([ceftEnabled]) do
+    begin
+      if lControl is TButton then
+      begin
+        lList.Add(TButton(lControl));
+      end;
+    end;
+
+    var lListOfStr := HigherOrder.Map<TButton, String>(
+      lList, function(const Item: TButton): String
+             begin
+               Result := String(Item.Caption).ToUpper;
+             end);
+    try
+      lbMap.Items.AddStrings(lListOfStr.ToArray);
+    finally
+      lListOfStr.Free;
+    end;
+  finally
+    lList.Free;
+  end;
+end;
+
 procedure TMainForm.btnMapAddStarsClick(Sender: TObject);
 var
   InputData, OutputData: TArray<string>;

sources/MVCFramework.Utils.pas

@@ -30,7 +30,8 @@ interface
 
 uses
   MVCFramework.Serializer.Commons, JsonDataObjects,
-  MVCFramework.DuckTyping, System.Classes, System.SysUtils;
+  MVCFramework.DuckTyping, System.Classes, System.SysUtils,
+  System.Generics.Collections;
 
 type
   EHOError = class(Exception)
@@ -54,19 +55,27 @@ type
   end;
 
   TMapClosure<T> = reference to function(const Item: T): T;
+  TMapClosure2<T1,T2> = reference to function(const Item: T1): T2;
   TForEachClosure<T> = reference to procedure(const Item: T);
   TMapReduceClosure<T> = reference to function(const Left: T; const Right: T): T;
   TPredicateClosure<T> = reference to function(const Item: T): Boolean;
 
   HigherOrder = class sealed
+  public
     class function Map<T>(const InputArray: TArray<T>;
-      const MapClosure: TMapClosure<T>): TArray<T>;
+      const MapClosure: TMapClosure<T>): TArray<T>; overload;
+    class function Map<T1,T2>(const List: TEnumerable<T1>;
+      const MapClosure: TMapClosure2<T1, T2>): TList<T2>; overload;
+    class function Map<T1,T2>(const InputArray: TArray<T1>;
+      const MapClosure: TMapClosure2<T1, T2>): TList<T2>; overload;
     class function Reduce<T>(const InputArray: TArray<T>;
       const ReduceFunction: TMapReduceClosure<T>; InitValue: T): T;
     class function Filter<T>(const InputArray: TArray<T>;
       const FilterFunction: TPredicateClosure<T>): TArray<T>;
     class procedure ForEach<T>(const InputArray: TArray<T>;
-      const ForEachClosure: TForEachClosure<T>);
+      const ForEachClosure: TForEachClosure<T>); overload;
+    class procedure ForEach<T>(const Enumerable: TEnumerable<T>;
+      const ForEachClosure: TForEachClosure<T>); overload;
   end;
 
 function NewJSONSerializer: IMVCJSONSerializer;
@@ -87,7 +96,6 @@ uses
   IdHashMessageDigest,
   IdHashSHA,
 {$ENDIF}
-  System.Generics.Collections,
   MVCFramework.Serializer.JsonDataObjects,
   MVCFramework.Commons,
   System.TypInfo;
@@ -241,6 +249,78 @@ begin
   end;
 end;
 
+class procedure HigherOrder.ForEach<T>(const Enumerable: TEnumerable<T>; const ForEachClosure: TForEachClosure<T>);
+var
+  lIdx: Integer;
+  lItem: T;
+begin
+  lIdx := 0;
+  try
+    for lItem in Enumerable do
+    begin
+      ForEachClosure(lItem);
+      Inc(lIdx);
+    end;
+  except
+    on E: Exception do
+    begin
+      raise EHOForEachError.CreateFmt
+        ('ForEach error at element %d - [Class: %s][Message: %s]',
+        [lIdx, E.ClassName, E.Message]);
+    end;
+  end;
+end;
+
+class function HigherOrder.Map<T1, T2>(const List: TEnumerable<T1>; const MapClosure: TMapClosure2<T1, T2>): TList<T2>;
+var
+  lIdx: Integer;
+  lItem: T1;
+begin
+  Result := nil;
+  lIdx := 0;
+  try
+    Result := TList<T2>.Create;
+    for lItem in List do
+    begin
+      Result.Add(MapClosure(lItem));
+      Inc(lIdx);
+    end;
+  except
+    on E: Exception do
+    begin
+      Result.Free;
+      raise EHOMapError.CreateFmt
+        ('Map error at index %d - [Class: %s][Message: %s]',
+        [lIdx, E.ClassName, E.Message]);
+    end;
+  end;
+end;
+
+class function HigherOrder.Map<T1, T2>(const InputArray: TArray<T1>; const MapClosure: TMapClosure2<T1, T2>): TList<T2>;
+var
+  lIdx: Integer;
+  lItem: T1;
+begin
+  Result := nil;
+  lIdx := 0;
+  try
+    Result := TList<T2>.Create;
+    for lItem in InputArray do
+    begin
+      Result.Add(MapClosure(lItem));
+      Inc(lIdx);
+    end;
+  except
+    on E: Exception do
+    begin
+      Result.Free;
+      raise EHOMapError.CreateFmt
+        ('Map error at index %d - [Class: %s][Message: %s]',
+        [lIdx, E.ClassName, E.Message]);
+    end;
+  end;
+end;
+
 class function HigherOrder.Map<T>(const InputArray: TArray<T>;
   const MapClosure: TMapClosure<T>): TArray<T>;
 var