How to build sets of letters for the currently selected language

Problem/Question/Abstract:

Is there any way to enumerate the contents of a set? Just now I have a set of char, each char is a lower case character, and need to add the corresponding upper case characters to the set. Any other way than looping through the set range and do an inclusion check each time?

Answer:

No. If you are after building sets of letters for the currently selected language you could do it using API functions like IsCharAlpha and IsCharUpper:


unit Charsets;

interface

type
  TCharSet = set of AnsiChar;

const
  Signs: TCharset = ['-', '+'];
  Numerals: TCharset = ['0'..'9'];
  HexNumerals: TCharset = ['A'..'F', 'a'..'f', '0'..'9'];
  IntegerChars: TCharset = ['0'..'9', '-', '+'];
var
  Letters, LowerCaseLetters, UpperCaseLetters: TCharSet;
  FloatChars, SciFloatChars: TCharset;
  AlphaNum, NonAlphaNum: TCharset;

  { Need to call this again when locale changes.  }
procedure SetupCharsets;

implementation

uses
  Windows, Sysutils;

procedure SetupCharsets;
var
  ch: AnsiChar;
begin
  LowerCaseLetters := [];
  UpperCaseLetters := [];
  AlphaNum := [];
  NonAlphaNum := [];
  for ch := Low(ch) to High(ch) do
  begin
    if IsCharAlpha(ch) then
      if IsCharUpper(ch) then
        Include(UpperCaseLetters, ch)
      else
        Include(LowerCaseLetters, ch);
    if IsCharAlphanumeric(ch) then
      Include(AlphaNum, ch)
    else
      Include(NonAlphaNum, ch);
  end;
  Letters := LowerCaseLetters + UpperCaseLetters;
  FloatChars := IntegerChars;
  Include(FloatChars, DecimalSeparator);
  SciFloatChars := FloatChars + ['e', 'E'];
end;

initialization
  SetupCharsets;

end.