$ include "seed7_05.s7i";

const func integer: repeatLength (in string: text) is func
  result
    var integer: length is 0;
  local
    var integer: pos is 0;
  begin
    for pos range succ(length(text) div 2) downto 1 until length <> 0 do
      if startsWith(text, text[pos ..]) then
        length := pred(pos);
      end if;
    end for;
  end func;

const proc: main is func
  local
    var string: line is "";
    var integer: length is 0;
  begin
    for line range [] ("1001110011", "1110111011", "0010010010", "1010101010",
                       "1111111111", "0100101101", "0100100", "101", "11", "00", "1") do
      length := repeatLength(line);
      if length = 0 then
        writeln("No rep-string for " <& literal(line));
      else
        writeln("Longest rep-string for " <& literal(line) <& ": " <& literal(line[.. length]));
      end if;
    end for;
  end func;