Join {

              get initial outer and inner tuples                INITIALIZE

              do forever {

                  while (outer != inner) {                    SKIP_TEST

                      if (outer < inner)

                          advance outer                        SKIPOUTER_ADVANCE

                      else

                          advance inner                        SKIPINNER_ADVANCE

                  }

                  mark inner position                            SKIP_TEST

                  do forever {

                      while (outer == inner) {

                          join tuples                            JOINTUPLES

                          advance inner position                NEXTINNER

                      }

                      advance outer position                    NEXTOUTER

                      if (outer == mark)                        TESTOUTER

                          restore inner position to mark        TESTOUTER

                      else

                          break    // return to top of outer loop

                  }

              }

          }