Author: Christian Cristofori

Sometime Pos is not enough, because you need to find the position of the first 
character of a sub string in a string from the end of that string. There's the 
solution.

Answer:
1   
2   function RPos(Substr: string; S: string): Integer;
3   var
4     i: Integer;
5   begin
6     Result := 0;
7     if ((Length(S) > 0) and (Length(Substr) > 0)) then
8       if (Length(S) >= Length(Substr)) then
9         for i:= (Length(S) - Length(Substr)) downto 1 do
10          if (Copy(S, i, Length(Substr)) = Substr) then
11          begin
12            Result := i;
13            Exit;
14          end;
15  end;