if ($i) {
    if ($DB::dbline[$i] == 0) {
      $s->output("Line $i not breakable.\n");
    }
    else {
      $DB::dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
    }
  }
}

sub _find_subline {
  my $name = shift;
  $name =~ s/\'/::/;
  $name = "${DB::package}\:\:" . $name if $name !~ /::/;
  $name = "main" . $name if substr($name,0,2) eq "::";
  my($fname, $from, $to) = ($DB::sub{$name} =~ /^(.*):(\d+)-(\d+)$/);
  if ($from) {
    local *DB::dbline = "::_<$fname";
    ++$from while $DB::dbline[$from] == 0 && $from < $to;
    return $from;
  }
  return undef;
}

sub clr_breaks {
  my $s = shift;
  my $i;
  if (@_) {
    while (@_) {
      $i = shift;
      $i = _find_subline($i) if ($i =~ /\D/);
      $s->output("Subroutine not found.\n") unless $i;
      if (defined $DB::dbline{$i}) {
        $DB::dbline{$i} =~ s/^[^\0]+//;
        if ($DB::dbline{$i} =~ s/^\0?$//) {
          delete $DB::dbline{$i};
        }
      }
    }
  }
  else {
    for ($i = 1; $i <= $#DB::dbline ; $i++) {
      if (defined $DB::dbline{$i}) {
        $DB::dbline{$i} =~ s/^[^\0]+//;
        if ($DB::dbline{$i} =~ s/^\0?$//) {
          delete $DB::dbline{$i};
        }
      }
    }
  }
}

sub set_action {
  my $s = shift;
  my $i = shift;
  my $act = shift;
  $i = _find_subline($i) if ($i =~ /\D/);
  $s->output("Subroutine not found.\n") unless $i;
  if ($i) {
    if ($DB::dbline[$i] == 0) {
      $s->output("Line $i not actionable.\n");
    }
    else {
      $DB::dbline{$i} =~ s/\0[^\0]*//;
      $DB::dbline{$i} .= "\0" . $act;
    }
  }
}

sub clr_actions {
  my $s = shift;
  my $i;
  if (@_) {
    while (@_) {
      my $i = shift;
      $i = _find_subline($i) if ($i =~ /\D/);
      $s->output("Subroutine not found.\n") unless $i;
      if ($i && $DB::dbline[$i] != 0) {
	$DB::dbline{$i} =~ s/\0[^\0]*//;
	delete $DB::dbline{$i} if $DB::dbline{$i} =~ s/^\0?$//;
      }
    }
  }
  else {
    for ($i = 1; $i <= $#DB::dbline ; $i++) {
      if (defined $DB::dbline{$i}) {
	$DB::dbline{$i} =~ s/\0[^\0]*//;
	delete $DB::dbline{$i} if $DB::dbline{$i} =~ s/^\0?$//;
      }
    }
  }
}

sub prestop {
  my ($client, $val) = @_;
  return defined($val) ? $preeval->{$client} = $val : $preeval->{$client};
}

sub poststop {
  my ($client, $val) = @_;