Index: head/usr.bin/sgmlfmt/sgmlfmt.1
===================================================================
--- head/usr.bin/sgmlfmt/sgmlfmt.1	(revision 10482)
+++ head/usr.bin/sgmlfmt/sgmlfmt.1	(revision 10483)
@@ -1,131 +1,164 @@
-.Dd August 28, 1995
+.Dd August 30, 1995
 .Os FreeBSD 2.0.5
 .Dt SGMLFMT 1
 .Sh NAME
 .Nm sgmlfmt
 .Nd Formats SGML files tagged according to the linuxdoc DTD.
 .Sh SYNOPSIS
 .Nm
-.Fl Ar format Op Fl Ar format... 
-.Op Fl Ar links
-.Ar 
+.Fl f Ar format
+.Op Fl links
+.Op Fl i Ar name ...
+.Ar file
 .Sh DESCRIPTION
 The
 .Nm
 command reads SGML files tagged according to the linuxdoc DTD,
 validates them using the
 .Xr sgmls 1
 parser and then converts them to the specified output format.
 The input file must include the following document type
 declaration before any uncommented text:
 .Bd -literal -offset indent
 <!DOCTYPE linuxdoc PUBLIC "-//FreeBSD//DTD linuxdoc//EN">
 .Ed
-.Pp
-The 
-.Fl Ar format
-options for output include the following:
+.Pp Options for
+.Nm
+include the following:
 .Bl -tag -width Ds
-.It Fl html
+.It Fl f Ar format
+Determines the output format which can be one of the following:
+.Bl -tag -width Ds
+.It Ar html
 Generates a set of linked HTML files suitable for use with an
 HTML browser.  A top level file,
 .Pa file.html ,
 contains the title, author, date, abstract and brief table of
 contents for the document.  A file
 .Pa file_toc.html
 contains a complete table of contents.  A series of files named
 .Pa file1.html ,
 .Pa file2.html ...
 .Pa filen.html
 contain the actual text of the document.
-.It Fl latex
+.It Ar latex
 Generates a single output file with the extension
 .Pa .tex
 suitable for processing with LaTeX.  Note that the LaTeX style
 file
 .Pa /usr/share/sgml/FreeBSD/lib/linuxdoc.sty
 must be accessible to LaTeX for correct processing.
-.It Fl ascii
+.It Ar ascii
 Generates a single output file with the extension 
 .Pa .ascii
 suitable for viewing on an ASCII terminal. 
-.It Fl nroff
+.It Ar nroff
 Generates a single output file with the extension
 .Pa .nroff
 suitable processing with
 .Xr nroff 1
 or
 .Xr groff 1 .
 This is actually an intermediate conversion used by the
-.Fl ascii
+.Fl f Ar ascii
 format option.
+.El
 .It Fl links
 When used with the
-.Fl html
-option, for each <label id="foo"> in the document source 
+.Fl f Ar html
+option, for each 
+.Li <label id="foo">
+in the document source 
 .Nm
 generates a symbolic link
 .Pa foo.html
 pointing to the numbered
 .Pa .html
 file containing the reference.  Since the number of the file
 containing a particular section can change when a document
 is modified, this provides a convenient hook by which separate
 documents can provide links into another document without the
 links becoming invalid when the target document is modified.
 When creating a symbolic link, any occurence of a slash (/) in label 
 is replaced with percent (%), while any occurence of a space is replaced
 with an underscore (_).
+.It Fl i Ar name
+Pretend that
+.Dl <!ENTITY % name "INCLUDE">
+occurs at the start of the document type declaration subset in
+the document entity.  Since repeated definitions of an entity are
+ignored, this definition will take precedence over any other
+definitions of this entity in the document type declaration.
+Multiple 
+.Fl i
+options are allowed.  If the declaration replaces the reserved
+name INCLUDE then the new reserved name will be the replacement
+text of the entity.  Typically the document type declaration will
+contain
+.Dl <!ENTITY % name "IGNORE">
+and will use 
+.Li %name; 
+in the status keyword specification of a
+marked section declaration.  In this case the effect of the
+option will be to cause the marked section not to be ignored.
 .El
 .Pp
 If the input file name ends with
 .Pa .sgml ,
 the extension may be omitted on the command line.
 In all cases, the output files are created in the current working
 directory.
 .Sh FILES
 .Pa /usr/share/sgml/FreeBSD/dtd/linuxdoc
 - the linuxdoc DTD.
 .Pp
 .Pa /usr/share/sgml/FreeBSD/rep/
 - directory containing replacement files for
 .Xr sgmlsasp 1 .
 .Pp
 .Pa /usr/share/sgml/FreeBSD/lib/linuxdoc.sty
 - the LaTeX style used in documents produced with the
 .Fl latex
 format option.
 .Sh SEE ALSO
 .Xr sgmls 1 ,
 .Xr sgmlsasp 1 ,
 .Xr groff 1
 .Sh HISTORY
 The
 .Nm
 command appeared in Version 2.0.5 FreeBSD UNIX.
 .Sh AUTHORS
 The
 .Nm
 command was written by John Fieber
 .Aq jfieber@FreeBSD.org .
 The linuxdoc DTD was written by Matt Welsh
 .Aq mdw@cs.cornell.edu 
 and based on the Qwertz DTD written by Tom Gordon
 .Aq thomas.gordon@gmd.de .
 .Sh BUGS
 The ASCII output has many, many bugs including no table of
 contents, no meaningful cross references, and numerous formatting
 errors.
 .Pp
 A line in the SGML source file beginning with a period (.) will
 confuse
 .Xr groff 1
 which is used to generate ASCII output.  
 .Pp
 The divison of the sources file into separate HTML files is
 currently fixed. 
 .Pp
 Although legal according to the DTD, it the ascii formatting gets botched if
-the <heading>...</heading> tags are omitted following a
-sectioning tag such as <sect>.  Furthermore, all text between
-<heading> and </heading> must be on one line.
+the 
+.Li <heading>
+.No ...
+.Li </heading>
+tags are omitted following a
+sectioning tag such as
+.Li <sect> .  Furthermore, all text between
+.Li <heading>
+and
+.Li </heading>
+must be on one line.
Index: head/usr.bin/sgmlfmt/sgmlfmt.pl
===================================================================
--- head/usr.bin/sgmlfmt/sgmlfmt.pl	(revision 10482)
+++ head/usr.bin/sgmlfmt/sgmlfmt.pl	(revision 10483)
@@ -1,686 +1,711 @@
 #!/usr/bin/perl
-# $Id: sgmlfmt.pl,v 1.4 1995/08/25 23:26:49 jfieber Exp $
+# $Id: sgmlfmt.pl,v 1.5 1995/08/29 01:02:12 jfieber Exp $
 
 # Format an sgml document tagged according to the linuxdoc DTD.
 # by John Fieber <jfieber@freebsd.org> for the FreeBSD documentation
 # project.  
 #
 # Usage: sgmlformat -format [-format ...] [-links] inputfile [inputfile ...]
 #
 #  -format              outputfile         format
 #  -------------------------------------------------------------
 #   -html               inputfile.html     HTML
 #   -txt | -ascii       inputfile.ascii    ascii text
 #   -tex | -latex       inputfile.tex      LaTeX
 #   -nroff              inputfile.nroff    groff for ms macros
 #   -ps                 inputfile.ps       postscript
 #
 #   -links              For each <label id="foo">, make a symbolic
 #                       link foo.html -> inputfile-n.html.  
 #
 # Bugs:
 #
 # Text lines that start with a period (.) confuse the conversions that
 # use groff.  The workaround is to make sure the SGML source doesn't
 # have any periods at the beginning of a line.
 #
 # Although legal by the DTD, it the ascii formatting gets botched if
 # the <heading></heading> tags are omitted following a <sect?>.
 #
 # The whole approach of using sgmlsasp and passing a few things
 # through for processing by this script is doomed.  This whole thing
 # needs to be re-thought and a better DTD should be used anyway.
 #
 #######################################################################
 
 # Look in a couple places for the SGML DTD and replacement files
 #
 
+require 'newgetopt.pl';
+
 if (-d "$ENV{'HOME'}/lib/sgml/FreeBSD") {
     $sgmldir = "$ENV{'HOME'}/lib/sgml";
 }
 elsif (-d "$ENV{'HOME'}/sgml/FreeBSD") {
     $sgmldir = "$ENV{'HOME'}/sgml";
 }
 elsif (-d "/usr/share/sgml/FreeBSD" ) {
     $sgmldir = "/usr/share/sgml";
 }
 else {
     die "Cannot locate sgml files!\n";
 }
 
 #
 # Locate the DTD, an SGML declaration, and the replacement files
 #
 
 $dtdbase = "$sgmldir/FreeBSD";
 $dtd = "$dtdbase/dtd/linuxdoc";
 if (-f "$dtd.dec") {
     $decl = "$dtd.dec";
 }
 else {
     $decl = "";
 }
 $replbase = "$dtdbase/rep";
 
 if (! $ENV{"SGML_PATH"}) {
     $ENV{"SGML_PATH"} = "$sgmldir/%O/%C/%T";
 }
 
+sub usage {
+    print "Usage:\n";
+    print "sgmlfmt -f <format> [-i <namea> [-i <nameb> ...]] [-links] filename[.sgml]\n";
+    print "where <format> is one of: html, latex, ascii, nroff\n";
+}
 #
 # Look for the file specified on the command line
 #
 
 sub getfile {
     local($filearg) = @_;
     if (-f "$filearg.sgml") {
 	$file = "$filearg.sgml";
     }
     elsif (-f $filearg) {
 	$file = $filearg;
     }
     else {
 	return 0;
     }
     $fileroot = $file;
     $fileroot =~ s/.*\///;	# drop the path
     $fileroot =~ s/\.sgml$//;	# drop the .sgml
     $filepath = $file;
     $filepath =~ s/\/*[^\/]*$//;	
     if ($filepath eq "") {
 	$ENV{"SGML_PATH"} .= ":.";
     }
     else {
 	$ENV{"SGML_PATH"} .= ":$filepath/%S:.";
     }
     return 1;
 }
 
 #
 # A function to run sgmls and sgmlsasp on the input file.
 #
 # Arguments:
 #   1. A file handle for the output
 #   2. A replacement file (directory actually)
 #
 
 sub sgmlparse {
     local($fhandle, $replacement) = @_;
+    $defines = join(" -i ", @opt_i);
+    if ($defines ne "") {
+	$defines = "-i $defines";
+    }
     $ENV{'SGML_PATH'} = "$replbase/$replacement.%N:$ENV{'SGML_PATH'}";
-    open($fhandle, "sgmls $decl $file | sgmlsasp $replbase/$replacement.mapping |");
+    open($fhandle, "sgmls $defines $decl $file | sgmlsasp $replbase/$replacement.mapping |");
 }
 
 #
 # Generate nroff output
 #
 
 sub gen_nroff {
     open (outfile, ">$fileroot.nroff");
     &sgmlparse(infile, "nroff");
     $\ = "\n";              # automatically add newline on print
     while (<infile>) {
 	chop;
 	# This is supposed to ensure that no text line starts
 	# with a dot (.), thus confusing groff, but it doesn't
 	# appear to work.
 	unless (/^\.DS/.../^\.DE/) {
 	    s/^[ \t]{1,}(.*)/$1/g;
 	}
 	s/^\.[ \t].*/\\\&$&/g;
 	print outfile;
     }
     $\ = "";
     close(infile);
     close(outfile);
 }
 
 #
 # Generate ASCII output using groff
 #
 
 sub gen_ascii {
     &sgmlparse(infile, "nroff");
     open(outfile, "| groff -T ascii -t -ms | col -b > $fileroot.ascii");
     while (<infile>) {
 	print outfile;
     }
     close(infile);
     close(outfile);
 }
 
 #
 # Generate Postscript output using groff (this is suboptimal
 # for printed output!)
 #
 
 sub gen_ps {
     &sgmlparse(infile, "grops");
     open(outfile, "| groff -T ps -t -ms > $fileroot.ps");
     while (<infile>) {
 	print outfile;
     }
     close(infile);
     close(outfile);
 }
 
 #
 # Generate LaTeX output
 #
 
 sub gen_latex {
     open(outfile, ">$fileroot.tex");
     &sgmlparse(infile, "latex");
     while (<infile>) {
 	print outfile;
     }
     close(infile);
     close(outfile);
 }
 
 
 #
 # Generate HTML output.
 #
 # HTML is generated in two passes.  
 #
 # The first pass takes the output from sgmlsasp and gathers information
 # about the structure of the document that is used in the sceond pass
 # for splitting the file into separate files.  Targets for cross
 # references are also stored in this pass.
 #
 # Based on the information from the first pass, the second pass
 # generates a numbered series of HTML files, a "toplevel" file
 # containing the title, author, abstract and a brief table of
 # contents.  A detailed table of contents is also generated.  The
 # second pass generates links for cross references and URLs.
 
 #
 # Tunable parameters
 #
 $maxlevel = 3;			# max section depth
 $num_depth = 4;			# depth of numbering
 $m_depth = 2;			# depth of menus
 
 
 $sc = 0;			# section counter
 $filecount = 0;			# file counter
 
 # Other variables:
 #
 #  st_xxxx  - Section Table.  Arrays containing information about a
 #             given section.  To be accesssed via the section counter $sc.
 #             
 #  st_ol    - The output level of the given section.  I.E. how many
 #             levels from the table of contents does it lie in terms
 #             of HTML files which is distinct from <sect1>, <sect2> etc.
 #             levels. 
 #
 #  st_sl    - The absolute depth of a section.  Contrast st_ol.
 # 
 #  st_num   - The section number in the form X.Y.Z....
 #
 #  st_file  - The HTML file the section belongs to.
 #
 #  st_header - The text of the section title.
 # 
 #  st_parent - The section number of the given sections parent.
 
 sub gen_html {
     local($i, $sl);
     $tmpfile = "/tmp/sgmlf.$$";
 
     open(bar, ">$tmpfile");
 #    print STDERR "(Pass 1...";
     &sgmlparse(foo, "html");
     while (<foo>) {
 	print bar;
 	# count up the number of files to be generated
 	# and gather assorted info about the document structure
 	if (/^<@@sect>/) {
 	    $sl++;		# current section level
 	    $sc++;		# current section number
 	    $st_sl[$sc] = $sl;
 
 	    # In case this section has subsections, set the parent
 	    # pointer for this level to point at this section.
 	    $parent_pointer[$sl] = $sc;
 
 	    # Figure out who is the parent if this section.
 	    $st_parent[$sc] = $parent_pointer[$sl - 1];
 
 	    # Per level counters
 	    $counter[$sl]++;
 	    $counter[$sl + 1] = 0;
 
 	    # calculate the section number in the form x.y.z.
 	    if ($sl <= $num_depth) {
 		$st_num[$sc] = $st_num[$st_parent[$sc]] . "$counter[$sl].";
 	    }
 
 	    # calculate the file number and output level
 	    if ($sl <= $maxlevel) {
 		$filecount++;
 		$st_ol[$sc] = $sl;
 	    }
 	    else {
 		$st_ol[$sc] = $maxlevel;
 	    }
 
 	    $st_file[$sc] = $filecount;
 
 	    # Calculate the highest level node in which this
 	    # node should appear as a menu item.  
 	    $st_pl[$sc] = $sl - $m_depth;
 	    if ($st_pl[$sc] < 0) {
 		$st_pl[$sc] = 0;
 	    }
 	    if ($st_pl[$sc] > $maxlevel) { 
 		$st_pl[$sc] = $maxlevel;
 	    } 
 	}
 	if (/^<@@endsect>/) {
 	    $sl--;
 	}
 
 	# record section titles
 	if (/^<@@head>/) {
 	    chop;
 	    s/^<@@head>//;
 	    $st_header[$sc] = $_;
 	}
 
 	# record the section number that a label occurs in
 	if (/^<@@label>/) {
 	    chop;
 	    s/^<@@label>//;
 	    if ($references{$_} eq "") {
 		$references{$_} = "$filecount";
-		if ($genlinks) {
+		if ($opt_links) {
 		    &extlink($_, "${fileroot}${filecount}.html");
 		}
 	    }
 	    else {
 		print STDERR "Warning: the label `$_' is multiply-defined.\n";
 	    }
 	}
     }
     close(bar);
 
     open(foofile, $tmpfile);
     &html2html(foofile, "boo");
 
     unlink($tmpfile);
 }
 
 #
 # HTML conversion, pass number 2
 #
 
 sub html2html {
     local($infile, $outfile) = @_;
     local($i);
 
     $sc = 0;
     push(@scs, $sc);
 
     open(tocfile, ">${fileroot}_toc.html");
     print tocfile "<HTML>\n";
 
     while (<$infile>) {
 	# change `<' and `>' to `&lt;' and `&gt;' in <pre></pre>
 	if (/<pre>/.../<\/pre>/) {
 	    s/</\&lt;/g;
 	    s/\&lt;([\/]*)pre>/<\1pre>/g;
 	    s/>/\&gt;/g;
 	    s/<([\/]*)pre\&gt;/<\1pre>/g;
 	}
 
 	# remove extraneous empty paragraphs (it is arguable that this
  	# is really a bug with the DTD, but changing it would break
  	# almost every document written to this DTD.)
 	s/<p><\/p>//;
 
       tagsw: {
 	  # titles and headings
 	  if (s/^<@@title>//) {
 	      chop;
 	      $st_header[0] = $_;
 	      $st_parent[0] = -1;
 	      print tocfile "<HEAD>\n<TITLE>$st_header[0]</TITLE>\n</HEAD>\n";
 	      print tocfile "<H1>$st_header[0]</H1>\n";
 	      $header[$st_ol[$sc]] = 
 		  "<HTML>\n<HEAD>\n<TITLE>$st_header[0]</TITLE>\n" . 
 		      "</HEAD>\n<BODY>\n<H1>$st_header[0]</H1>\n"; 
 	      $footer[$st_ol[$sc]] = "</BODY>\n</HTML>\n";
 	      last tagsw;
 	  }
 
 	  #
 	  # HEADER begin
 	  #
 	  if (s/^<@@head>//) {
 	      chop;
 
 	      if ($part == 1) {
 		  $text[0] .= "<H1>Part $partnum:<BR>$_";
 		  last tagsw;
 	      }
 
 	      $href = "\"${fileroot}$st_file[$sc].html#$sc\"";
 
 	      # set up headers and footers
 	      if ($st_sl[$sc] > 0 && $st_sl[$sc] <= $maxlevel) {
 		  $header[$st_ol[$sc]] = 
 		      "<HTML>\n<HEAD>\n<TITLE>$_</TITLE>\n</HEAD>\n" .
 			  "<BODY>\n$navbar[$st_ol[$sc]]\n<HR>\n";
 		  $footer[$st_ol[$sc]] =
 		      "<HR>\n$navbar[$st_ol[$sc]]\n</BODY>\n</HTML>";
 	      }
 
 	      # Add this to the master table of contents
 	      print tocfile "<DD>$st_num[$sc] " . 
 		  "<A HREF=$href>$_";
 
 	      # Calculate the <H?> level to use in the HTML file
 	      $hlevel = $st_sl[$sc] - $st_ol[$sc] + 2;
 	      $shlevel = $st_sl[$sc] - $st_ol[$sc] + 3;
 
 	      $i = $st_ol[$sc];
 
 	      # Add the section header
 	      $text[$i] .= "<H$hlevel><A NAME=\"$sc\"></A>$st_num[$sc] $_";
 	      $i--;
 	      
 	      # And also to the parent 
 	      if ($st_sl[$sc] == $st_ol[$sc] && $i >= 0) {
 		  $text[$i] .= "<H$shlevel>$st_num[$sc] " . 
 			  "<A HREF=$href>$_";
 		  $i--;
 	      }
 
 	      # and to the grandparents
 	      for (; $i >= $st_pl[$sc];  $i--) {
 		  $text[$i] .= "<DD>$st_num[$sc] " .
 		      "<A HREF=$href>$_";
 	      }
 
 	      last tagsw;
 	  }
 
 	  #
 	  # HEADER end
 	  #
 	  if (s/^<@@endhead>//) {
 	      if ($part == 1) {
 		  $text[0] .= "</H1>\n";
 		  $part = 0;
 		  last tagsw;
 	      }
 	      print tocfile "</A></DD>\n";
 
 	      $i = $st_ol[$sc];
 
 	      # Close the section header
 	      $text[$i] .= "</H$hlevel>\n";
 	      $i--;
 
 	      # in the parent...
 	      if ($st_sl[$sc] == $st_ol[$sc] && $i >= 0) {
 		  $text[$i] .= "</A></H$shlevel>\n";
 		  $i--;
 	      }
 
 	      # in the grandparent...
 	      for (; $i >= $st_pl[$sc];  $i--) {
 		  $text[$i] .= "</A></DD>\n";
 	      }
 	      last tagsw;
 	  }
 	  
 	  # sectioning
 	  if (s/^<@@part>//) {
 	      $part = 1;
 	      $partnum++;
 	      last tagsw;
 	  }
 
 	  #
 	  # BEGINNING of a section
 	  #
 	  if (s/^<@@sect>//) {
 	      # Increment the section counter and save it on a stack
 	      # for future reference.
 	      $sc++;
 	      push(@scs, $sc);
 
 	      # Set up the navigation bar
 	      if ($st_file[$sc] > $st_file[$sc - 1]) {
 		  &navbar($st_file[$sc], $filecount, $sc);
 	      }
 
 	      # Prepare for menu entries in the table of contents and
 	      # parent file(s).
 	      if ($st_sl[$sc - 1] < $st_sl[$sc]) {
 		  print tocfile "<DL>\n";
 		  $i = $st_ol[$sc] - 1 - ($st_sl[$sc] == $st_ol[$sc]);
 		  for (; $i >= $st_pl[$sc];  $i--) {
 		      $text[$i] .= "<DL>\n";
 		  }
 	      }
 	      last tagsw;
 	  }
 
 	  #
 	  # END of a section
 	  #
 	  if (s/^<@@endsect>//) {
 	      
 	      # Remember the section number! Subsections may have
 	      # altered the global $sc variable.
 	      local ($lsc) = pop(@scs);
 
 	      # Close off subsection menus we may have created in
 	      # parent file(s).
 	      if ($st_sl[$lsc] > $st_sl[$sc + 1]) {
 		  print tocfile "</DL>\n";
 		  $i = $st_ol[$lsc] - 1 - ($st_sl[$lsc] == $st_ol[$lsc]);
 		  for (; $i >= $st_pl[$lsc];  $i--) {
 		      $text[$i] .= "</DL>\n";
 		  }
 	      }
 
 	      # If this section is below $maxlevel, write it now.
 	      if ($st_sl[$lsc] <= $maxlevel) {
 		  open(SECOUT, ">${fileroot}$st_file[$lsc].html");
 		  print SECOUT "$header[$st_ol[$lsc]]  $text[$st_ol[$lsc]] " . 
 		      "$footer[$st_ol[$lsc]]";
 		  $text[$st_ol[$lsc]] = "";
 		  close(SECOUT);
 	      }
 	      last tagsw;
 	  }		
 
 	  # cross references
 	  if (s/^<@@label>//) {
 	      chop;
 	      $text[$st_ol[$sc]] .= "<A NAME=\"$_\"></A>";
 	      last tagsw;
 	  }
 	  if (s/^<@@ref>//) {
 	      chop;
 	      $refname = $_;
 	      if ($references{$_} eq "") {
 		  print "Warning: Reference to $_ has no defined target\n";
 	      }
 	      else {
 		  $text[$st_ol[$sc]] .= 
 		      "<A HREF=\"${fileroot}$references{$_}.html#$_\">";
 	      }
 	      last tagsw;
 	  }
 	  if (s/^<@@endref>//) {
 #	      $text[$st_ol[$sc]] .= "</A>";
 	      last tagsw;
 	  }
 	  if (s/^<@@refnam>//) {
 	      $text[$st_ol[$sc]] .= "$refname</A>";
 	      last tagsw;
 	  }
 	  # URLs
 	  if (s/^<@@url>//) {
 	      chop;
 	      $urlname = $_;
 	      $text[$st_ol[$sc]] .= "<A HREF=\"$urlname\">";
 	      last tagsw;
 	  }
 	  if (s/^<@@urlnam>//) {
 	      $text[$st_ol[$sc]] .= "$urlname</A>";
 	      last tagsw;
 	  }
 	  if (s/^<@@endurl>//) {
 #	      $text[$st_ol[$sc]] .= "</A>";
 	      last tagsw;
 	  }
 	  
 
 	  # If nothing else did anything with this line, just print it.
 	  $text[$st_ol[$sc]] .= "$_";
       }
     }
 
     print tocfile "</HTML>";
     open(SECOUT, ">$fileroot.html");
     print SECOUT "$header[0] $text[0] $footer[0]";
     close(SECOUT);
     close tocfile;
 }
 
 # navbar
 #
 # Generate a navigation bar to go on the top and bottom of the page.
 
 sub navbar {
     local ($fnum, $fmax, $sc) = @_;
     local ($i, $itext, $prv, $nxt);
 
     # Generate the section hierarchy
 
     $navbar[$st_ol[$sc]] =
 	"<B><A HREF=\"${fileroot}.html\"><EM>$st_header[0]</EM></A>\n";
     $i = $st_parent[$sc];
     while ($i > 0) {
 	$itext = " : <A HREF=\"${fileroot}$st_file[$i].html\"><EM>$st_header[$i]</EM></A>\n$itext";
 	$i = $st_parent[$i];
     }
     $navbar[$st_ol[$sc]] .= "$itext : <EM>$st_header[$sc]</EM><BR>\n";
 
     # Generate previous and next pointers
 
     # Previous pointer must be in a different file AND must be at the
     # same or higher section level.  If the current node is the
     # beginning of a chapter, then previous will go to the beginning
     # of the previous chapter, not the end of the previous chapter.
 
     $prv = $sc;
     while ($prv >= 0 && $st_file[$prv] >= $st_file[$sc] - 1) { 
 	$prv--; 
     }
     $prv++;
     $navbar[$st_ol[$sc]] .=
 	"Previous: <A HREF=\"${fileroot}$st_file[$prv].html\"><EM>$st_header[$prv]</EM></A><BR>\n";
 
     # Then next pointer must be in a higher numbered file OR the home
     # page of the document.
 
     $nxt = $sc;
     if ($st_file[$nxt] == $filecount) { 
 	$nxt = 0; 
     }
     else {
 	while ($st_file[$nxt] == $st_file[$sc]) {
 	    $nxt++;
 	}
     }
 
     $navbar[$st_ol[$sc]] .=
 	"Next: <A HREF=\"${fileroot}$st_file[$nxt].html\"><EM>$st_header[$nxt]</EM></A>\n";
 
     $navbar[$st_ol[$sc]] .= "</B>\n";
 
 }
 
 
 # extlink
 #
 # creates a symbolic link from the name in a reference to the numbered
 # html file.  Since the file number that any given section has is 
 # subject to change as the document goes through revisions, this allows
 # for a fixed target that separate documents can hook into.
 #
 # Slashes (/) in the reference are converted to percents (%) while
 # spaces ( ) are converted to underscores (_);
 
 sub extlink {
     local ($ref, $fn) = @_;
 
     $ref =~ s/\//%/g;
     $ref =~ s/ /_/g;
 
     $file = "$ref.html";
 
     if (-e $file) {
 	if (-l $file) {
 	    unlink($file);
 	    symlink($fn, $file);
 	}
 	else {
 	    print "Warning: $file exists and is not a symbolic link\n";
 	}
     }
     else {
 	symlink($fn, $file);
     }
 }
 
 # Now, read the command line and take appropriate action
 
-$fcount = 0;
-for (@ARGV) {
-    if (/^-.*/) {
-	s/^-//;
-	$gen{$_} = 1;
+sub main {
+    # Check arguments
+    if (!&NGetOpt('f=s', 'links', 'i:s@')) {
+	&usage;
+	exit 1;
     }
-    else {
-	@infiles[$fcount] = $_;
-	$fcount++;
+    if (@ARGV == 0) {
+	print "An input file must be specified.\n";
+	&usage;
+	exit 1;
     }
-}
+    if (&getfile($ARGV[0]) == 0) {
+	print "Cannot locate specified file: $ARGV[0]\n";
+	&usage;
+	exit 1;
+    }
 
-for ($i = 0; $i < $fcount; $i++) {
-    if (&getfile($infiles[$i])) {
-	if ($gen{'html'}) { 
-	    print "generating $fileroot.html";
-	    if ($gen{'links'}) {
-		$genlinks = 1;
-		print " with external links";
-	    }
-	    else {
-		$genlinks = 0;
-	    }
-	    print "...\n"; &gen_html(); }
-	if ($gen{'tex'} || $gen{'latex'}) { 
-	    print "generating $fileroot.tex...\n"; &gen_latex(); }
-	if ($gen{'nroff'}) { 
-	    print "generating $fileroot.nroff...\n"; &gen_nroff(); }
-	if ($gen{'txt'} || $gen{'ascii'}) { 
-	    print "generating $fileroot.ascii...\n"; &gen_ascii(); }
-	if ($gen{'ps'}) { 
-	    print "generating $fileroot.ps...\n"; &gen_ps(); }
+    # Generate output
+    if ($opt_f eq 'html') {
+	print "generating $fileroot.html";
+	if ($opt_links == 1) {
+	    print " with external links";
+	}
+	print "...\n"; &gen_html(); 
     }
+    elsif ($opt_f eq 'tex' || $opt_f eq 'latex') {
+	print "generating $fileroot.tex...\n"; &gen_latex(); 
+    }
+    elsif ($opt_f eq 'nroff') { 
+	print "generating $fileroot.nroff...\n"; &gen_nroff();
+    }
+    elsif ($opt_f eq 'ascii') {
+	print "generating $fileroot.ascii...\n"; &gen_ascii(); 
+    }
+    elsif ($opt_f eq 'ps') { 
+	print "generating $fileroot.ps...\n"; &gen_ps(); 
+    }
     else {
-	print "Input file $infiles[$i] not found\n";
+	if ($opt_f eq "") {
+	    print "An output format must be specified with the -f option.\n";
+	}
+	else {
+	    print "\"$opt_f\" is an unknown output format.\n";
+	}
+	&usage;
+	exit 1;
     }
+
 }
+
+&main;
 
 exit 0;