unclear (Duplicate identifier) error
lazarus / 62-General

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fcu · 2018-02-22 14:21

Hi
try to compile this with fpc 3.0.4 & fpc 3.1.1 , gives this error
(Duplicate identifier "tNode$1$crc7ED07D64")
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i {$mode
delphi}type        tNode<T> = record          data : T;          next
: ^tNode<T>;        end;         tLList<T> = object          procedure
add(const item : T);        private          head : ^tNode<T>;       
end; procedure tLList<T>.add(const item : T);var     tmp : ^tNode<T>;
// Error: Duplicate identifier "tNode$1$crc7ED07D64"begin       
//end; beginend. 
am i doing something wrong or its fpc bug ?

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ASerge · 2018-02-22 15:48

When mode is objfpc:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
Project1;{$APPTYPE CONSOLE}{$MODE OBJFPC} type  generic TNode<T> =
object  public type    PNode = ^TNode;  public var    Data: T;   
Next: PNode;  end;   generic TList<T> = object  private type    PNode
= specialize TNode<T>.PNode;  private var    FHead: PNode;  public   
constructor Init;    destructor Done;    procedure Add(const Item:
T);    procedure PrintAll;  end; constructor TList.Init;begin  FHead
:= nil;end; destructor TList.Done;var  Prev: PNode;begin  while FHead
<> nil do  begin    Prev := FHead;    FHead := FHead^.Next;   
Dispose(Prev);  end;end; procedure TList.Add(const Item: T);var  Tmp:
PNode;begin  New(Tmp);  Tmp^.Data := Item;  Tmp^.Next := FHead;  FHead
:= Tmp;end; procedure TList.PrintAll;var  Cur: PNode;begin  Cur :=
FHead;  while Cur <> nil do  begin    Writeln(Cur^.Data);    Cur :=
Cur^.Next;  end;end; var  List: specialize TList<Integer>;begin 
List.Init;  List.Add(10);  List.Add(20);  List.PrintAll;  List.Done; 
Readln;end.

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fcu · 2018-02-22 16:17

thanks ASerge . but my attention was : what is the cause of this error
just curious , why ( head : ^tNode<T>; ) was allowed inside tLList
class and not in the (add ) procedure  ?

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ASerge · 2018-02-22 16:41

Quote from: fcu on February 22, 2018, 05:17:28 pmthanks ASerge . but
my attention was : what is the cause of this error
just curious , why ( head : ^tNode<T>; ) was allowed inside tLList
class and not in the (add ) procedure  ?
An example for both modes, where it is clearly visible that the types
of pointers are different!
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
Project1;{$APPTYPE CONSOLE}{-$MODE DELPHI}{$MODE OBJFPC} type  {$IFDEF
FPC_OBJFPC}generic{$ENDIF}TNode<T> = object  public type    PItemNode
= ^TNode{$IFDEF FPC_DELPHI}<T>{$ENDIF};  public var    Data: T;   
Next: PItemNode;  end;   {$IFDEF FPC_OBJFPC}generic{$ENDIF}TList<T> =
object  private type    PListNode = {$IFDEF
FPC_OBJFPC}specialize{$ENDIF}TNode<T>.PItemNode;  private var   
FHead: PListNode;  public    constructor Init;    destructor Done;   
procedure Add(const Item: T);    procedure PrintAll;  end; constructor
TList{$IFDEF FPC_DELPHI}<T>{$ENDIF}.Init;begin  FHead :=
nil;end; destructor TList{$IFDEF FPC_DELPHI}<T>{$ENDIF}.Done;var 
Prev: PListNode;begin  while FHead <> nil do  begin    Prev := FHead; 
  FHead := FHead^.Next;    Dispose(Prev);  end;end; procedure
TList{$IFDEF FPC_DELPHI}<T>{$ENDIF}.Add(const Item: T);var  Tmp:
PListNode;begin  New(Tmp);  Tmp^.Data := Item;  Tmp^.Next := FHead; 
FHead := Tmp;end; procedure TList{$IFDEF
FPC_DELPHI}<T>{$ENDIF}.PrintAll;var  Cur: PListNode;begin  Cur :=
FHead;  while Cur <> nil do  begin    Writeln(Cur^.Data);    Cur :=
Cur^.Next;  end;end; var  List: {$IFDEF
FPC_OBJFPC}specialize{$ENDIF}TList<Integer>;begin  List.Init; 
List.Add(10);  List.Add(20);  List.PrintAll;  List.Done;  Readln;end.
Those, when it is written ^TNode<T> the compiler does not understand
what to choose.