SetLength (Invalid Argument)

BackDreamBackDream
edited 8:25PM in FastScript
Hello,

I'm trying to make this simple script work: 
var
  s: string;
begin
  s := 'hello world';
  SetLength(s, 5);  
end.
but everytime the scripter gets to the SetLength procedure it raises an Invalid Argument exception.

Looking into your code (v1.6, fs_isysrtti.pas, line 197) i read: 
AddMethod('procedure SetLength(var S: Variant; L: Integer)', CallMethod5, FCatStr);
so I suppose when the S (variant) is evaluated it appears to represent a variable of the wrong type. Exception comes up at line 571 of the Variants.pas file of Delphi 7 (update 1).

Is function/procedure/method overloading supported? Can you help and/or fix the problem?

Thank you in advance.

Comments

  • AlexTZAlexTZ
    edited 8:25PM
    Fix the fs_isysrtti.pas file:
    function TFunctions.CallMethod5(Instance: TObject; ClassType: TClass;
  const MethodName: String; var Params: Variant): Variant;
var
  s: String;
  v: Variant;
begin
  if MethodName = 'LENGTH' then
    Result := Length(Params[0])
  else if MethodName = 'COPY' then
    Result := Copy(Params[0], Integer(Params[1]), Integer(Params[2]))
  else if MethodName = 'POS' then
    Result := Pos(Params[0], Params[1])
  else if MethodName = 'DELETE' then
  begin
    s := Params[0];
    Delete(s, Integer(Params[1]), Integer(Params[2]));
    Params[0] := s;
  end
  else if MethodName = 'INSERT' then
  begin
    s := Params[1];
    Insert(Params[0], s, Integer(Params[2]));
    Params[1] := s;
  end
  else if MethodName = 'UPPERCASE' then
    Result := AnsiUppercase(Params[0])
  else if MethodName = 'LOWERCASE' then
    Result := AnsiLowercase(Params[0])
  else if MethodName = 'TRIM' then
    Result := Trim(Params[0])
  else if MethodName = 'NAMECASE' then
    Result := NameCase(Params[0])
  else if MethodName = 'COMPARETEXT' then
    Result := AnsiCompareText(Params[0], Params[1])
  else if MethodName = 'CHR' then
    Result := Chr(Integer(Params[0]))
  else if MethodName = 'ORD' then
    Result := Ord(String(Params[0])[1])
  else if MethodName = 'SETLENGTH' then
  begin
    if (TVarData(Params[0]).VType = varString) or
      (TVarData(Params[0]).VType = varOleStr) then
    begin
      s := Params[0];
      SetLength(s, Integer(Params[1]));
      Params[0] := s;
    end
    else
    begin
      v := Params[0];
      VarArrayRedim(v, Integer(Params[1]));
      Params[0] := v;
    end;
  end
end;

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