$ include "seed7_05.s7i";

const func array bitset: powerSet (in bitset: baseSet) is func
  result
    var array bitset: pwrSet is [] (bitset.value);
  local
    var integer: element is 0;
    var integer: index is 0;
    var bitset: aSet is bitset.value;
  begin
    for element range baseSet do
      for key index range pwrSet do
        aSet := pwrSet[index];
        if element not in aSet then
          incl(aSet, element);
          pwrSet &:= aSet;
        end if;
      end for;
    end for;
  end func;

const proc: main is func
  local
    var bitset: aSet is bitset.value;
  begin
    for aSet range powerSet({1, 2, 3, 4}) do
      writeln(aSet);
    end for;
  end func;