Re: [fpc-pascal] evaluation of set constant

[Howard Page-Clark]

On 22/12/10 1:15, Torsten Bonde Christiansen wrote:

type
   TMyType = (a, b, c ,d);
   TMyTypes = set of TMyTypes;

const
   SetX:        TMyTypes = (a, b);
   SetY:        TMyTypes = (c, d);
   SetCombined: TMyTypes = SetX + SetY;   // this gives me an "Error: Illegal 
expression"

Because you have not declared your sets with the correct square brackets.
Try this sample:

unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, Forms, Controls, Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  end;

  TMyType = (a, b, c , d);
  TMyTypes = set of TMyType;

const
  SetX:      TMyTypes = [a, b];
  SetY:      TMyTypes = [c, d];
  typeNames: array [TMyType] of string = ('a', 'b', 'c', 'd');

var
  Form1: TForm1;

implementation

{$R *.lfm}

{ TForm1 }

procedure TForm1.Button1Click(Sender: TObject);
var SetCombined: TMyTypes;
    myType: TMyType;
    s: string;
begin
  s := '';
  setCombined :=  SetY + SetX;
  for myType in setCombined do
    s := s + typenames[myType];
  ShowMessage(s);
end;

end.

HTH

Howard
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