Что не так с обработкой клавиш?

uses graphabc;
 
var
  GetKeyPressed: boolean;
  a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z: boolean;
 
type
  Input = class
    
    class function GetKeyPressed(Key: string): boolean;
    begin
      GetKeyPressed := false;
      if (a = true) and (Key = 'a') then GetKeyPressed := true;
    end;
  end;
 
procedure KeyIsDown(DownKey: integer);
begin
  if DownKey = 65 then a := true;
end;
 
procedure KeyIsUp(UpKey: integer);
begin
  if UpKey = 65 then a := false;
end;
 
begin
  OnKeyDown := KeyIsDown;
  OnKeyUp := KeyIsUp;
  if Input.GetKeyPressed('a') then TextOut(0, 0, 'Key A is pressed;');
end.

  TextOut(0, 20, 'The End.');

uses
  GraphABC;
 
type
  Input = class
    Key : Char;
    Pressed : Boolean;
    
    constructor (Key : Char);
    begin
      Self.Key := Key; Pressed := False;
    end;
    
    procedure Down := Pressed := True;
    procedure Up   := Pressed := False;
    
    function GetKey := Key;
    function GetKeyPressed := Pressed;
    
    procedure Status(X, Y : Integer) :=
      TextOut(X, Y, 'Key "' + Key + '" is ' + (Not Pressed?'not ':'') + 'pressed.');
  end;
 
var KeyA := New Input('a');
 
procedure KeyIsDown(DownKey: integer);
begin
  case DownKey of
    65 : KeyA.Down;
  end;
end;
 
procedure KeyIsUp(UpKey: integer);
begin
  case UpKey of
    65 : KeyA.Up;
  end;
end;
 
begin
  OnKeyDown := KeyIsDown;
  OnKeyUp := KeyIsUp;
  repeat
    KeyA.Status(0, 0);
    Sleep(250);
  until False;
end.