Hello,
currently, I play with the Help authoring Tool
www.HelpNDoc.com and its Pascal Script Editor and Pascal Engine.
I can use TStringList, but I would like implement a own Version of this Class.
For this, I have the following Code:
unit GenericTemplate;
interface
type
TVariantType = (
vtEmpty,
vtBoolean,
vtChar,
vtInteger,
vtString );
TVariant = record
VarType = record
vtBoolean: Boolean;
vtChar: Char;
vtInteger: Integer;
vtString: String;
end;
end;
type
TStringNode = class(TObject)
public
data: string;
prev, next: TStringNode;
constructor Create(const p: TStringNode; const n: TStringNode); overload;
constructor Create(const p: TStringNode); overload;
constructor Create; overload;
end;
type
TStringArray = class(TObject)
private
PNode: TStringNode;
Head: TStringNode;
FCount: Integer;
public
constructor Create(InitialSize: Integer = 0);
procedure Add(const AValue: String);
(* function Get(Index: Integer): String;
procedure SetValue(Index: Integer; const Value: String);*)
function Count: Integer;
end;
implementation
{ TStringNode }
constructor TStringNode.Create;
begin
inherited Create;
prev := nil;
next := nil;
end;
constructor TStringNode.Create(const p: TStringNode);
begin
inherited Create;
if p = nil then raise Exception.Create('TStringNode is nil');
prev := p;
next := nil;
end;
constructor TStringNode.Create(const p: TStringNode; const n: TStringNode);
begin
inherited Create;
if p = nil then raise Exception.Create('TStringNode parent is nil.');
if n = nil then raise Exception.Create('TStringNode next is nil.');
prev := p;
next := n;
end;
{ TStringArray }
constructor TStringArray.Create(InitialSize: Integer);
var
idx: Integer;
begin
inherited Create;
for idx := 0 to initialsize do
begin
Print(idx);
Add(IntToStr(idx) + ': 11');
end;
end;
procedure TStringArray.Add(const AValue: String);
var
n, p: TStringNode;
begin
if PNode = nil then
PNode := TStringNode.Create;
p := PNode;
n := TStringNode.Create;
n.data := AValue;
PNode.next := n;
PNode.prev := p;
end;
function TStringArray.Count: Integer;
var
p: TStringNode;
begin
p := PNode;
while True do
begin
if p.prev = nil then break;
print(p.data);
p := PNode.prev;
end;
result := FCount;
end;
initialization
var
sa: TStringArray;
Print('start...');
sa := TStringArray.Create(2);
try
sa.count;
finally
sa.Free;
Print('done.');
end;
end.
But when I try to "add" Strings to the Array Class, I stuck into a infinite loop when I try to read out the Elements.
So, my Question is now: how can I Add and print Elements when I use next and prev ?
The problem is, I can not use records, because I run into problems with:
foo = record
next: foo;
end;
foo will not evulate.
And I can not use Pointers like:
Pfoo = ^TFoo;
TFoo = FoFo;
Thanks for helping hands
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