delphi convert set type to array of character-CodePudding

Currently in a legacy code I have a set which I want to convert to array of string so i can pass this as a parameter for existing method.

  //Existing code to be used and converted
  const
  North = 'F';
  Pay = 'P';
  Lynk = 'L';  
  
  TCharSet = set of AnsiChar;
  MySet: TCharSet = [North, Pay, Lynk];

So my question is how do i convert above set to a array of character? Is this doable?

After doing some research found below code and that seems to have enum used to create a set and using TypeInfo to convert the enum to string.

//**Working code**  

  TMyEnum = (meFirst, meSecond, meThird);
  TMySet = set of TMyEnum;
  
function MySetToString(MySet: TMySet): string;
var
  i: TMyEnum;
begin
  Result := '';
  // one way to iterate
  for i := Low(i) to High(i) do
    if i in MySet then
      Result := Result   GetEnumName(TypeInfo(TMyEnum), Ord(i))   ' ';
end;

// call to above method

  set1 := [meFirst, meSecond, meThird];
  ShowMessage(MySetToString(set1));

Any help really appreciated.

CodePudding user response：

//**Working code**  

TMyEnum = (meFirst, meSecond, meThird);
TMySet = set of TMyEnum;
TStrArr = TArray<STRING>;

function MySetToStrings(MySet: TMySet): TStrArr;
var
  i: TMyEnum;
begin
  SetLength(Result,0);
  // one way to iterate
  for i := Low(i) to High(i) do
    if i in MySet then
      Result := Result   [GetEnumName(TypeInfo(TMyEnum), Ord(i))]
end;

// call to above method

var set1 : TMySet;
var arr : TStrArr;
var s : String;

set1 := [meFirst, meSecond, meThird];
arr := MySetToStrings(set1);
for s in arr do ShowMessage(s);

UPDATE (after changed question):

TYPE TCharSet = SET OF AnsiChar;
TYPE TCharArr = TArray<AnsiChar>;

FUNCTION CharSetToCharArr(CONST CharSet : TCharSet) : TCharArr;
  VAR
    C : AnsiChar;

  BEGIN
    SetLength(Result,0);
    FOR C IN CharSet DO Result:=Result [C]
  END;

Your MySet will return this:

CharSetToCharArr(MySet) = ['F','L','P']

ie. a character array containing 3 elements, 'F', 'L' and 'P' in that order (they will always be in ANSI Ordinal order, as sets have no concept of "order").

CodePudding user response：

You can convert each element of the Set to a Char, using Char function. So the code could be something like this:

procedure TForm1.Button1Click(Sender: TObject);
type
  TCharSet = set of AnsiChar;
const
  North = 'F';
  Pay = 'P';
  Lynk = 'L';
var
  MySet: TCharSet;
  myArr: Array of Char;
  c: AnsiChar;
  i: Integer;
begin
  MySet := [North, Pay, Lynk];

  i := 0;
  for c in MySet do
  begin
    SetLength(myArr, Length(myArr) 1);
    myArr[i] := Char(c);
    i := i   1;
  end;

  for i := 0 to Length(myArr)-1 do
    ShowMessage(myArr[i]);
end;