return $1;
}

sub next {
  my $s = shift;
  $DB::single = 2;
  $running = 1;
}

sub step {
  my $s = shift;
  $DB::single = 1;
  $running = 1;
}

sub cont {
  my $s = shift;
  my $i = shift;
  $s->set_tbreak($i) if $i;
  for ($i = 0; $i <= $#stack;) {
	$stack[$i++] &= ~1;
  }
  $DB::single = 0;
  $running = 1;
}

####
# XXX caller must experimentally determine $i (since it depends
# on how many client call frames are between this call and the DB call).
# Such is life.
#
sub ret {
  my $s = shift;
  my $i = shift;      # how many levels to get to DB sub
  $i = 0 unless defined $i;
  $stack[$#stack-$i] |= 1;
  $DB::single = 0;
  $running = 1;
}

####
# XXX caller must experimentally determine $start (since it depends
# on how many client call frames are between this call and the DB call).
# Such is life.
#
sub backtrace {
  my $self = shift;
  my $start = shift;
  my($p,$f,$l,$s,$h,$w,$e,$r,$a, @a, @ret,$i);
  $start = 1 unless $start;
  for ($i = $start; ($p,$f,$l,$s,$h,$w,$e,$r) = caller($i); $i++) {
    @a = @DB::args;
    for (@a) {
      s/'/\\'/g;
      s/([^\0]*)/'$1'/ unless /^-?[\d.]+$/;
      s/([\200-\377])/sprintf("M-%c",ord($1)&0177)/eg;
      s/([\0-\37\177])/sprintf("^%c",ord($1)^64)/eg;
    }
    $w = $w ? '@ = ' : '$ = ';
    $a = $h ? '(' . join(', ', @a) . ')' : '';
    $e =~ s/\n\s*\;\s*\Z// if $e;
    $e =~ s/[\\\']/\\$1/g if $e;
    if ($r) {
      $s = "require '$e'";
    } elsif (defined $r) {
      $s = "eval '$e'";
    } elsif ($s eq '(eval)') {
      $s = "eval {...}";
    }
    $f = "file `$f'" unless $f eq '-e';
    push @ret, "$w&$s$a from $f line $l";
    last if $DB::signal;
  }
  return @ret;
}

sub _outputall {
  my $c;
  for $c (@clients) {
    $c->output(@_);
  }
}

sub trace_toggle {
  my $s = shift;
  $DB::trace = !$DB::trace;
}


####
# without args: returns all defined subroutine names
# with subname args: returns a listref [file, start, end]
#
sub subs {
  my $s = shift;
  if (@_) {
    my(@ret) = ();
    while (@_) {
      my $name = shift;
      push @ret, [$DB::sub{$name} =~ /^(.*)\:(\d+)-(\d+)$/]