Super Simple Text Translation

unit SimpleTextTranslation;
// Lars Fosdal (lars.fosdal@gmail.com) - 2015.03.26 - Super Simple Text Translation
// Add a language, and it is IMPOSSIBLE to miss a translation
// Not much declaration that has to be done.
// Constants can be added anywhere, and lookup is cheap (?).
// You can change the translation by setting a single variable.
// You can change the text of a specific translation by assigning new values.

interface
uses
  SysUtils;

const
  _ = string('');

type
  TPSDLanguage = (ENG, NOR, SWE, GER);
  T_X = Array[TPSDLanguage] of String;

function XLT(const T_ARG:T_X):String; overload;
function XLT(const T_ARG:T_X; const Arguments: Array of const):String; overload;

procedure XLT_Lang(const Lang: TPSDLanguage); overload;
function XLT_Lang: TPSDLanguage; overload;

const
  T_X_Language: T_X = ('ENG', 'NOR', 'SWE', 'GER');
  T_Ready: T_X = ('Ready', 'Klar', _, _);
  T_Yes: T_X = ('Yes', 'Ja', _, _);
  T_No: T_X = ('No', 'Nei', 'Nej', 'Nein');
  T_TheFirst: T_X = ('First', 'Første', 'Första', 'Erste');
  T_TheLast: T_X = ('Last', 'Siste', 'Sista', 'Letzte');

  // Examples
  // T_Date: T_X = ('mm d, yyyy', 'yyyy.mm.dd', 'dd.mm.yy', 'dd.MMM, yyyy');
  // t := FormatDateTime(XLT(T_Date), Now);
  //
  // T_Issue: T_X = ('Issue %d', '%d. utgave', 'Nummer %d', 'Ausgabe %d');
  // t := XLT(T_Issue, [IssueNumber]);

implementation

var
  Language: TPSDLanguage = ENG;

function XLT(const T_ARG:T_X):String;
var
  lang: TPSDLanguage;
begin
  Result := T_ARG[Language];
  if Result = _
  then begin
    lang := High(TPSDLanguage);
    while (lang > Low(TPSDLanguage)) and (T_ARG[Lang] = _)
    do Dec(lang);
    Result := T_ARG[lang];
  end;
  if Result = _
   then raise Exception.Create('No text in T_ARG for language=' + T_X_Language[Language]);
end;

function XLT(const T_ARG:T_X; const Arguments: Array of const):String;
begin
  Result := XLT(T_ARG);
  Result := Format(Result, Arguments);
end;

procedure XLT_Lang(const Lang: TPSDLanguage);
begin
  Language := Lang;
end;

function XLT_Lang: TPSDLanguage;
begin
  Result := Language;
end;

initialization
  XLT_Lang(ENG);
end.