#!/usr/bin/perl

sub head
{
  if($pageno>1)
  {
    print "\n";
    $lineno++;
    print "_c_o_m_m_e_n_t";
    print "#072";
  }
  my $i=$linewidth/2-length($pageno);
  print " " x $i.(-$pageno)."-";
  my $i=$linewidth/2-2-length($program);
  print " " x $i.$program."\n";
  $lineno=1;
  if($pageno>1)
  {
    print ";\n";
    $lineno++;
  }
  $pageno++;
}

sub expandtab
{
  my $l1 = $_[0];
  my $l2 = "";
  my $l3 = length($l1);
# print "l1: $l1 l3: $l3\n";
  my $p=0;
  for(my $i=0; $i<$l3; $i++)
  {
    my $c=substr($l1,$i,1);
    if($c eq "\t")
    {
      do
      {
	$l2 .= " ";
	$p++;
      } while(($p%8)!=0);
    }
    else
    {
      $l2 .= $c;
      $p++ if(($c ne "_") && ($c ne "|"));
    }
  }
  return $l2;
}



$indent=0;
$pageheight=48;
$skiplines=6;
$lineno=1;
$pageno=1;
$linewidth=72;
$program="PLOT-2";
head();

while($l = <>)
{
  chomp($l);
  $l = expandtab($l);
  $lineno++;
  $newpage=0;
  if($l =~ /_b_e_g_i_n/)
  {
    $indent++;
  }
  elsif($l =~ /_e_n_d/)
  {
    $indent--;
  }
  elsif($l =~ /_p_r_o_c_e_d_u_r_e/)
  {
    if($indent==1)
    {
      $newpage=1;
    }
  }
  if($lineno>($pageheight-$skiplines))
  {
    $newpage=1;
  }
  if($newpage)
  {
    head();
  }
# print $indent." ".$l."\n";
  print $l."\n";
}