* doc/groff.texinfo: Document new .O register and add cross

reference entries.

* NEWS: Updated.

* src/devices/grohtml/grohtml.man: Document new -V and -y options.

* src/devices/grohtml/html-table.cpp: Add support for XHTML 1.1.
(html_table:: emit_colspan, html_table::emit_td): New methods.
(html_table::emit_col):  Use html_table::emit_td.
(html_table::emit_table_header): Use html_table::emit_colspan if
dialect xhtml is specified.
(html_table::finish_row): Updated.

* src/devices/grohtml/html-table.h (html_table): Declare
emit_colspan, emit_td.

* src/devices/grohtml/html-text.cpp: Modified tags to comply with
xhtml if this dialect was requested.

* src/devices/grohtml/html-text.h (html_dialect): New enumeration.
(html_text): Add new variable `dialect'.

* src/devices/grohtml/post-html.cpp: Modify header tags to be XHTML
compliant.
(valid_flag, groff_sig, dialect): New global variables.
(html_printer::handle_valid_flag, html_printer::do_math,
html_printer::write_html_anchor, html_printer::write_xhtml_anchor,
html_printer::do_math, html_printer::handle_valid_flag): New
methods.
(html_printer::emit_line, html_printer::emit_raw,
html_printer::do_check_center, html_printer::write_title,
write_rule, html_printer::writeHeadMetaStyle, generate_img_src,
html_printer::begin_page): Altered to be XHTML compliant.
(html_printer::write_header): Updated.
(html_printer::troff_tag): Call do_math.
(html_printer::insert_split_file, html_printer::do_file_components,
html_printer::write_navigation): Create XHTML file components if
necessary and also produces a groff signature if requested.
(~html_printer): Call writeHeadMetaStyle at appropriate places
depending upon html_dialect.
(html_printer::special): Handle new tags `html<?p>' and `math<?p>'.
(main): Added options -x, -V, and -y.
(usage): Updated.

* src/preproc/eqn/box.cpp: Create a distinction between
the MathML device and the XHTML device.
(do_text): Issue a newline at the end of the equation if XHTML was
specified.
(box::top_level): Prefix the output of an equation by the .MATHML
macro.
(output_string): Suppress \n if XHTML was specified.

* src/preproc/eqn/main.cpp (xhtml): New global flag.
(inline_equation): Skip leading spaces after inline equation for
XHTML device.
(main): Set `xhtml' flag if `-Tmathml:xhtml' is specified.

* src/preproc/eqn/eqn.h (xhtml): New external flag.

* src/preproc/eqn/text.cpp (entity_table): Fix typo.

* src/preproc/html/pre-html.cpp (html_dialect): New enumeration.
(dialect, eqn_flag): New global variables.
(html_system): Improve debugging support.
(alterDeviceTo): Test for -Txhtml when altering device to the image
device and reset to -Txhtml.
(addZ): Renamed to...
(addArg): This.
Introducea a general parameter.
(print_args): New debugging function.
(char_buffer::run_output_filter): Use print_args and addArg rather
than addZ.
(char_buffer::do_html, char_buffer::do_image): Add -rxhtml=1 command
line parameter as an argument to the html generation of text when
xhtml is needed.  Include -e on the command line if mathml is
required.
(scanArguments): Allow -e, -V, -y and -x options.
-V, -y are handled by the back end.  -e sets `eqn_flag'.
-x determines HTML dialect.

* src/roff/groff/groff.cpp (possible_command): New method
`clear_name'.
(main):  Set eflag if -e is present on command line.
Set is_xhtml if -Txhtml is present.
Pass `-x x' to the HTML pre and post processors.
Pass `-e' to the HTML pre processor if required.
Pass `-Tmathml:xhtml' to eqn if XHTML is requested.

* src/roff/troff/input.cpp (init_input_requests): Introduce new
number register `\n[.O]'.

* tmac/s.tmac: (LP): Use .nop for semantic sugar.
(cov*ab-init) reformat.
(@EQ): Use EQN-HTML-IMAGE and friends rather than HTML-IMAGE.
(CHECK-FOOTER-AND-KEEP): Define FS, FE such that they use
<cite></cite> for the html device rather than generate images for
footnotes.

* tmac/troffrc-end: Define EQN-HTML-IMAGE,
EQN-HTML-IMAGE-END, EQN-HTML-IMAGE-RIGHT,
EQN-HTML-IMAGE-LEFT, EQN-HTML-IMAGE-INLINE,
EQN-HTML-DO-IMAGE, EQN-HTML-IMAGE-END as null strings.

* tmac/www.tmac: (HTML<?p>): New macro.
(MATH<?p>): New macro.
(IMG, PIMG, MPIMG, HR): Use XHTML compliant syntax.
(www-emit-ltag): New macro.
(www-push-li): Updated.
(ULS): Ensure that tags are balanced in order by use of
www-emit-ltag.
(ULE): Likewise: Use www-emit-ltag and shut down paragraphs in
order.
(OLS, OLE, DLS, DLE): Ditto.
<global>: Define EQ and EN to EQN-HTML-IMAGE and EQN-HTML-IMAGE-END
respectively.
(www-li-ul, www-li-ol, www-li-dl): Updated.
(EQN-HTML-IMAGE, EQN-HTML-IMAGE-RIGHT, EQN-HTML-IMAGE-LEFT,
EQN-HTML-IMAGE-INLINE, EQN-HTML-DO-IMAGE, EQN-HTML-IMAGE-END,
MATHML): New macros.

6 files changed, 496 insertions, 109 deletions

diff --git a/src/devices/grohtml/grohtml.man b/src/devices/grohtml/grohtml.man
index a4d4ece0..d1c6d28c 100644
--- a/src/devices/grohtml/grohtml.man
+++ b/src/devices/grohtml/grohtml.man
@@ -1,5 +1,5 @@
 .ig
-Copyright (C) 1999-2000, 2001, 2002, 2003, 2004, 2006
+Copyright (C) 1999-2000, 2001, 2002, 2003, 2004, 2006, 2007
   Free Software Foundation, Inc.
 
 Permission is granted to make and distribute verbatim copies of this
@@ -58,6 +58,7 @@ grohtml \- html driver for groff
 .OP \-o \%image-vertical-offset
 .OP \-s size
 .OP \-S level
+.OP \-x \%html-dialect
 .RI "[\ " files\|.\|.\|. "\ ]"
 .br
 .ad \na
@@ -130,6 +131,24 @@ to place all image files into directory
 .IR dir .
 .
 .TP
+.B \-e
+This option should not be directly invoked by the user as it is
+an internal option utilized by
+.B groff
+when
+.B \-Thtml
+or
+.B \-Txhtml
+is specified.
+It is used by the
+.B grohtml
+preprocessor to determine whether
+.B eqn
+should attempt to produce MathML (if
+.B \-Txhtml
+is specified).
+.
+.TP
 .BI \-F dir
 Prepend directory
 .IB dir /dev name
@@ -241,6 +260,39 @@ split at the heading level (or higher) defined by
 .B \-v
 Print the version number.
 .
+.TP
+.B \-V
+Create an XHTML validator button at the bottom of each page of
+the document.
+.
+.TP
+.BI \-x dialect
+Select HTML dialect.
+Currently,
+.I dialect
+should be either the digit\~\c
+.B 4
+or the letter\~\c
+.B x
+which indicates whether
+.B grohtml
+should generate HTML\~4 or XHTML, respectively.
+This option should not be directly invoked by the user as it is
+an internal option utilized by
+.B groff
+when
+.B \-Thtml
+or
+.B \-Txhtml
+is specified.
+.
+.TP
+.B \-y
+Produce a right-justified groff signature at the end of the document.
+This is only generated if the
+.B \-V
+flag is also specified.
+.
 .
 .SH USAGE
 There are styles called
diff --git a/src/devices/grohtml/html-table.cpp b/src/devices/grohtml/html-table.cpp
index 7e5b2dc5..c752b766 100644
--- a/src/devices/grohtml/html-table.cpp
+++ b/src/devices/grohtml/html-table.cpp
@@ -1,5 +1,5 @@
 // -*- C++ -*-
-/* Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
  *
  *  Gaius Mulley (gaius@glam.ac.uk) wrote html-table.cpp
  *
@@ -41,6 +41,9 @@ Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */
 #   define FALSE (1==0)
 #endif
 
+extern html_dialect dialect;
+
+
 tabs::tabs ()
   : tab(NULL)
 {
@@ -294,7 +297,7 @@ void html_table::set_linelength (int linelen)
     }
     p = c;
   }
-  if (p != NULL && p->right > 0)
+  if (p != NULL && p->right > 0 && linelength > p->right)
     add_column(p->no+1, p->right, linelength, 'L');
 }
 
@@ -337,10 +340,12 @@ void html_table::emit_table_header (int space)
     out->nl();
 
     out->put_string("<table width=\"100%\"")
-      .put_string(" border=0 rules=\"none\" frame=\"void\"\n")
+      .put_string(" border=\"0\" rules=\"none\" frame=\"void\"\n")
       .put_string("       cellspacing=\"0\" cellpadding=\"0\"");
     out->put_string(">")
       .nl();
+    if (dialect == xhtml)
+      emit_colspan();
     out->put_string("<tr valign=\"top\" align=\"left\"");
     if (space) {
       out->put_string(" style=\"margin-top: ");
@@ -375,6 +380,82 @@ void html_table::set_space (int space)
 }
 
 /*
+ *  emit_colspan - emits a series of colspan entries defining the
+ *                 table columns.
+ */
+
+void html_table::emit_colspan (void)
+{
+  cols *b = columns;
+  cols *c = columns;
+  int   width = 0;
+
+  out->put_string("<colgroup>");
+  while (c != NULL) {
+    if (b != NULL && b != c && is_gap(b))
+      /*
+       *   blank column for gap
+       */
+      out->put_string("<col width=\"")
+	.put_number(is_gap(b))
+	.put_string("%\" class=\"center\"></col>")
+	.nl();
+    
+    width = (get_right(c)*100 + get_effective_linelength()/2)
+	      / get_effective_linelength()
+             - (c->left*100 + get_effective_linelength()/2)
+		/get_effective_linelength();
+    switch (c->alignment) {
+    case 'C':
+      out->put_string("<col width=\"")
+	  .put_number(width)
+	  .put_string("%\" class=\"center\"></col>")
+	  .nl();
+      break;
+    case 'R':
+      out->put_string("<col width=\"")
+	  .put_number(width)
+	  .put_string("%\" class=\"right\"></col>")
+	  .nl();
+      break;
+    default:
+      out->put_string("<col width=\"")
+	  .put_number(width)
+	  .put_string("%\"></col>")
+	  .nl();
+    }
+    b = c;
+    c = c->next;
+  }
+  out->put_string("</colgroup>").nl();
+}
+
+/*
+ *  emit_td - writes out a <td> tag with a corresponding width
+ *            if the dialect is html4.
+ */
+
+void html_table::emit_td (int percentage, const char *s)
+{
+  if (percentage) {
+    if (dialect == html4) {
+      out->put_string("<td width=\"")
+	.put_number(percentage)
+	.put_string("%\"");
+      if (s != NULL)
+	out->put_string(s);
+      out->nl();
+    }
+    else {
+      out->put_string("<td");
+      if (s != NULL)
+	out->put_string(s);
+      out->nl();
+    }
+  }
+}
+
+/*
  *  emit_col - moves onto column, n.
  */
 
@@ -405,11 +486,7 @@ void html_table::emit_col (int n)
     
     // have we a gap?
     if (last_col != NULL) {
-      if (is_gap(b))
-	out->put_string("<td width=\"")
-	    .put_number(is_gap(b))
-	    .put_string("%\"></td>")
-	    .nl();
+      emit_td(is_gap(b), "></td>");
       b = b->next;
     }
 
@@ -421,17 +498,9 @@ void html_table::emit_col (int n)
 		/ get_effective_linelength()
 	      - (b->left*100 + get_effective_linelength()/2)
 		  /get_effective_linelength();
-      if (width)
-	out->put_string("<td width=\"")
-	    .put_number(width)
-	    .put_string("%\"></td>")
-	    .nl();
+      emit_td(width, "></td>");
       // have we a gap?
-      if (is_gap(b))
-	out->put_string("<td width=\"")
-	    .put_number(is_gap(b))
-	    .put_string("%\"></td>")
-	    .nl();
+      emit_td(is_gap(b), "></td>");
       b = b->next;
     }
     width = (get_right(b)*100 + get_effective_linelength()/2)
@@ -440,22 +509,13 @@ void html_table::emit_col (int n)
 		/get_effective_linelength();
     switch (b->alignment) {
     case 'C':
-      out->put_string("<td width=\"")
-	  .put_number(width)
-	  .put_string("%\" align=center>")
-	  .nl();
+      emit_td(width, " align=center>");
       break;
     case 'R':
-      out->put_string("<td width=\"")
-	  .put_number(width)
-	  .put_string("%\" align=right>")
-	  .nl();
+      emit_td(width, " align=right>");
       break;
     default:
-      out->put_string("<td width=\"")
-	  .put_number(width)
-	  .put_string("%\">")
-	  .nl();
+      emit_td(width);
     }
     // remember column, b
     last_col = b;
@@ -477,7 +537,13 @@ void html_table::finish_row (void)
     
     if (n > 0)
       emit_col(n);
-    out->put_string("</td>").nl();
+#if 1
+    if (last_col != NULL) {
+      out->put_string("</td>");
+      last_col = NULL;
+    }
+#endif
+    out->put_string("</tr>").nl();
   }
 }
 
diff --git a/src/devices/grohtml/html-table.h b/src/devices/grohtml/html-table.h
index dc6cebe2..5f1cfe56 100644
--- a/src/devices/grohtml/html-table.h
+++ b/src/devices/grohtml/html-table.h
@@ -1,5 +1,5 @@
 // -*- C++ -*-
-/* Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
  *
  *  Gaius Mulley (gaius@glam.ac.uk) wrote html-table.h
  *
@@ -93,6 +93,8 @@ public:
   void  finish_row        (void);
   int   get_effective_linelength (void);
   void  set_space         (int space);
+  void  emit_colspan      (void);
+  void  emit_td           (int percentage, const char *s = ">");
 
   tabs          *tab_stops;    /* tab stop positions */
   simple_output *out;
@@ -121,7 +123,7 @@ public:
   // the indent is shutdown when it is deleted
 
 private:
-  void end     (void);
+  void end    (void);
   int         is_used;
   int         pg;        // values of the registers as passed via initialization
   int         ll;
diff --git a/src/devices/grohtml/html-text.cpp b/src/devices/grohtml/html-text.cpp
index b58d5e4a..f2b36025 100644
--- a/src/devices/grohtml/html-text.cpp
+++ b/src/devices/grohtml/html-text.cpp
@@ -1,5 +1,5 @@
 // -*- C++ -*-
-/* Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
+/* Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007
  * Free Software Foundation, Inc.
  *
  *  Gaius Mulley (gaius@glam.ac.uk) wrote html-text.cpp
@@ -44,10 +44,11 @@ Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */
 #undef DEBUGGING
 // #define DEBUGGING
 
-html_text::html_text (simple_output *op) :
-  stackptr(NULL), lastptr(NULL), out(op), space_emitted(TRUE),
-  current_indentation(-1), pageoffset(-1), linelength(-1),
-  blank_para(TRUE), start_space(FALSE)
+html_text::html_text (simple_output *op, html_dialect d) :
+  stackptr(NULL), lastptr(NULL), out(op), dialect(d),
+  space_emitted(TRUE), current_indentation(-1),
+  pageoffset(-1), linelength(-1), blank_para(TRUE),
+  start_space(FALSE)
 {
 }
 
@@ -165,8 +166,12 @@ void html_text::end_tag (tag_definition *t)
 		     delete t->indent;
 		   t->indent = NULL;
                    break;
-  case SMALL_TAG:  out->put_string("</small>"); break;
-  case BIG_TAG:    out->put_string("</big>"); break;
+  case SMALL_TAG:  if (dialect != xhtml || (! is_in_pre ()))
+                     out->put_string("</small>");
+                   break;
+  case BIG_TAG:    if (dialect != xhtml || (! is_in_pre ()))
+                     out->put_string("</big>");
+                   break;
   case COLOR_TAG:  out->put_string("</font>"); break;
 
   default:
@@ -196,8 +201,10 @@ void html_text::issue_tag (const char *tagname, const char *arg,
     out->put_string(STYLE_VERTICAL_SPACE);
     out->put_string("\"");
   }
+#if 0
   if (space == TRUE || space == FALSE)
     out->put_string(" valign=\"top\"");
+#endif
   out->put_string(">");
 }
 
@@ -258,8 +265,12 @@ void html_text::start_tag (tag_definition *t)
 		     issue_tag("", (char *)t->arg1);
 		   }
                    out->enable_newlines(FALSE); break;
-  case SMALL_TAG:  issue_tag("<small", (char *)t->arg1); break;
-  case BIG_TAG:    issue_tag("<big", (char *)t->arg1); break;
+  case SMALL_TAG:  if (dialect != xhtml || (! is_in_pre ()))
+                     issue_tag("<small", (char *)t->arg1);
+                   break;
+  case BIG_TAG:    if (dialect != xhtml || (! is_in_pre ()))
+                     issue_tag("<big", (char *)t->arg1);
+                   break;
   case BREAK_TAG:  break;
   case COLOR_TAG:  issue_color_begin(&t->col); break;
 
@@ -652,9 +663,11 @@ void html_text::do_emittext (const char *s, int length)
     int text = remove_break();
     check_emit_text(stackptr);
     if (text) {
-      if (is_present(PRE_TAG)) {
+      if (is_present(PRE_TAG))
 	out->nl();
-      } else
+      else if (dialect == xhtml)
+	out->put_string("<br/>").nl();
+      else
 	out->put_string("<br>").nl();
     }
   } else
diff --git a/src/devices/grohtml/html-text.h b/src/devices/grohtml/html-text.h
index e0e3cc75..d6e11cd8 100644
--- a/src/devices/grohtml/html-text.h
+++ b/src/devices/grohtml/html-text.h
@@ -1,5 +1,5 @@
 // -*- C++ -*-
-/* Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
+/* Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007
  * Free Software Foundation, Inc.
  *
  *  Gaius Mulley (gaius@glam.ac.uk) wrote html-text.h
@@ -32,6 +32,12 @@ Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */
 #define STYLE_VERTICAL_SPACE "1em"
 
 /*
+ *  supported html dialects.
+ */
+
+typedef enum {xhtml, html4} html_dialect;
+
+/*
  *  html tags
  */
 
@@ -56,7 +62,7 @@ typedef struct tag_definition {
 
 class html_text {
 public:
-         html_text         (simple_output *op);
+         html_text         (simple_output *op, html_dialect d);
         ~html_text         (void);
   void   flush_text        (void);
   void   do_emittext       (const char *s, int length);
@@ -105,6 +111,7 @@ private:
   tag_definition   *stackptr;    /* the current paragraph state */
   tag_definition   *lastptr;     /* the end of the stack        */
   simple_output    *out;
+  html_dialect      dialect;     /* which dialect of html?      */
   int               space_emitted;   /* just emitted a space?   */
   int               current_indentation;   /* current .in value */
   int               pageoffset;            /* .po value         */
diff --git a/src/devices/grohtml/post-html.cpp b/src/devices/grohtml/post-html.cpp
index 3d93dc72..4a6e0cbc 100644
--- a/src/devices/grohtml/post-html.cpp
+++ b/src/devices/grohtml/post-html.cpp
@@ -1,5 +1,5 @@
 // -*- C++ -*-
-/* Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006
+/* Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
  * Free Software Foundation, Inc.
  *
  *  Gaius Mulley (gaius@glam.ac.uk) wrote post-html.cpp
@@ -90,6 +90,10 @@ static int base_point_size = 0;                      /* which troff font size ma
 static int split_level = 2;                          /* what heading level to split at?          */
 static string head_info;                             /* user supplied information to be placed   */
                                                      /* into <head> </head>                      */
+static int valid_flag = FALSE;                       /* has user requested a valid flag at the   */
+                                                     /* end of each page?                        */
+static int groff_sig = FALSE;                        /* "This document was produced using"       */
+html_dialect dialect = html4;                        /* which html dialect should grohtml output */
 
 
 /*
@@ -1570,6 +1574,8 @@ void header_desc::write_headings (FILE *f, int force)
 
       headers.start_from_head();
       header_filename.start_from_head();
+      if (dialect == xhtml)
+	fputs("<p>", f);
       do {
 	g = headers.get_data();
 	fputs("<a href=\"", f);
@@ -1589,12 +1595,18 @@ void header_desc::write_headings (FILE *f, int force)
 	h++;
 	fputs("\">", f);
 	fputs(g->text_string, f);
-        fputs("</a><br>\n", f);
+        fputs("</a>", f);
+	if (dialect == xhtml)
+	  fputs("<br/>\n", f);
+	else
+	  fputs("<br>\n", f);
 	headers.move_right();
 	if (multiple_files && (! header_filename.is_empty()))
 	  header_filename.move_right();
       } while (! headers.is_equal_to_head());
       fputs("\n", f);
+      if (dialect == xhtml)
+	fputs("</p>\n", f);
     }
   }
 }
@@ -2091,6 +2103,10 @@ class html_printer : public printer {
   int  round_width                    (int x);
   void handle_tag_within_title        (text_glob *g);
   void writeHeadMetaStyle             (void);
+  void handle_valid_flag              (void);
+  void do_math                        (text_glob *g);
+  void write_html_anchor              (text_glob *h);
+  void write_xhtml_anchor             (text_glob *h);
   // ADD HERE
 
 public:
@@ -2167,7 +2183,10 @@ void html_printer::end_of_line()
 void html_printer::emit_line (text_glob *)
 {
   // --fixme-- needs to know the length in percentage
-  html.put_string("<hr>");
+  if (dialect == xhtml)
+    html.put_string("<hr/>");
+  else
+    html.put_string("<hr>");
 }
 
 /*
@@ -2206,13 +2225,22 @@ void html_printer::emit_raw (text_glob *g)
     switch (next_tag) {
 
     case CENTERED:
-      current_paragraph->do_para("align=center", space);
+      if (dialect == html4)
+	current_paragraph->do_para("align=\"center\"", space);
+      else
+	current_paragraph->do_para("class=\"center\"", space);
       break;
     case LEFT:
-      current_paragraph->do_para(&html, "align=left", get_troff_indent(), pageoffset, linelength, space);
+      if (dialect == html4)
+	current_paragraph->do_para(&html, "align=\"left\"", get_troff_indent(), pageoffset, linelength, space);
+      else
+	current_paragraph->do_para(&html, "class=\"left\"", get_troff_indent(), pageoffset, linelength, space);
       break;
     case RIGHT:
-      current_paragraph->do_para(&html, "align=right", get_troff_indent(), pageoffset, linelength, space);
+      if (dialect == html4)
+	current_paragraph->do_para(&html, "align=\"right\"", get_troff_indent(), pageoffset, linelength, space);
+      else
+	current_paragraph->do_para(&html, "class=\"right\"", get_troff_indent(), pageoffset, linelength, space);
       break;
     default:
       fatal("unknown enumeration");
@@ -2308,9 +2336,12 @@ static string &generate_img_src (const char *filename)
   while (filename && (filename[0] == ' ')) {
     filename++;
   }
-  if (exists(filename))
+  if (exists(filename)) {
     *s += string("<img src=\"") + filename + "\" "
 	  + "alt=\"Image " + filename + "\">";
+    if (dialect == xhtml)
+      *s += "</img>";
+  }
   return *s;
 }
 
@@ -2409,14 +2440,60 @@ void html_printer::do_title (void)
   }
 }
 
+/*
+ *  write_html_anchor - writes out an anchor.  The style of the anchor
+ *                      dependent upon simple_anchor.
+ */
+
+void html_printer::write_html_anchor (text_glob *h)
+{
+  if (dialect == html4) {
+    if (h != NULL) {
+      html.put_string("<a name=\"");
+      if (simple_anchors) {
+	string buffer(ANCHOR_TEMPLATE);
+
+	buffer += as_string(header.no_of_headings);
+	buffer += '\0';
+	html.put_string(buffer.contents());
+      } else
+	html.put_string(header.header_buffer);
+      html.put_string("\"></a>").nl();
+    }
+  }
+}
+
+/*
+ *  write_xhtml_anchor - writes out an anchor.  The style of the anchor
+ *                       dependent upon simple_anchor.
+ */
+
+void html_printer::write_xhtml_anchor (text_glob *h)
+{
+  if (dialect == xhtml) {
+    if (h != NULL) {
+      html.put_string(" id=\"");
+      if (simple_anchors) {
+	string buffer(ANCHOR_TEMPLATE);
+
+	buffer += as_string(header.no_of_headings);
+	buffer += '\0';
+	html.put_string(buffer.contents());
+      } else
+	html.put_string(header.header_buffer);
+      html.put_string("\"");
+    }
+  }
+}
+
 void html_printer::write_header (void)
 {
   if (! header.header_buffer.empty()) {
+    text_glob *a = NULL;
     int space = current_paragraph->retrieve_para_space() || seen_space;
 
-    if (header.header_level > 7) {
+    if (header.header_level > 7)
       header.header_level = 7;
-    }
 
     // firstly we must terminate any font and type faces
     current_paragraph->done_para();
@@ -2427,33 +2504,22 @@ void html_printer::write_header (void)
       header.no_of_headings++;
       style st;
 
-      text_glob *h=new text_glob();
-      h->text_glob_html(&st,
+      a = new text_glob();
+      a->text_glob_html(&st,
 			header.headings.add_string(header.header_buffer),
 			header.header_buffer.length(),
 			header.no_of_headings, header.header_level,
 			header.no_of_headings, header.header_level);
 
-      header.headers.add(h,
+      // and add this header to the header list
+      header.headers.add(a,
 			 header.no_of_headings,
 			 header.no_of_headings, header.no_of_headings,
-			 header.no_of_headings, header.no_of_headings);   // and add this header to the header list
-
-      // lastly we generate a tag
-
-      html.nl().nl().put_string("<a name=\"");
-      if (simple_anchors) {
-	string buffer(ANCHOR_TEMPLATE);
-
-	buffer += as_string(header.no_of_headings);
-	buffer += '\0';
-	html.put_string(buffer.contents());
-      } else {
-	html.put_string(header.header_buffer);
-      }
-      html.put_string("\"></a>").nl();
+			 header.no_of_headings, header.no_of_headings);
     }
 
+    html.nl().nl();
+
     if (manufacture_headings) {
       // line break before a header
       if (!current_paragraph->emitted_text())
@@ -2462,11 +2528,14 @@ void html_printer::write_header (void)
       if (header.header_level<4) {
 	html.put_string("<b><font size=\"+1\">");
 	html.put_string(header.header_buffer);
-	html.put_string("</font></b>").nl();
+	html.put_string("</font>").nl();
+	write_html_anchor(a);
+        html.put_string("</b>").nl();
       }
       else {
 	html.put_string("<b>");
-	html.put_string(header.header_buffer);
+	html.put_string(header.header_buffer).nl();
+	write_html_anchor(a);
 	html.put_string("</b>").nl();
       }
     }
@@ -2474,8 +2543,10 @@ void html_printer::write_header (void)
       // and now we issue the real header
       html.put_string("<h");
       html.put_number(header.header_level);
+      write_xhtml_anchor(a);
       html.put_string(">");
-      html.put_string(header.header_buffer);
+      html.put_string(header.header_buffer).nl();
+      write_html_anchor(a);
       html.put_string("</h");
       html.put_number(header.header_level);
       html.put_string(">").nl();
@@ -2810,10 +2881,15 @@ void html_printer::do_check_center(void)
 	int space = current_paragraph->retrieve_para_space() || seen_space;
 	current_paragraph->done_para();
 	supress_sub_sup = TRUE;
-	current_paragraph->do_para("align=center", space);
+	if (dialect == html4)
+	  current_paragraph->do_para("align=\"center\"", space);
+	else
+	  current_paragraph->do_para("class=\"center\"", space);
       } else
-	if (strcmp("align=center",
-		   current_paragraph->get_alignment()) != 0) {
+	if ((strcmp("align=\"center\"",
+		    current_paragraph->get_alignment()) != 0) &&
+	    (strcmp("class=\"center\"",
+		    current_paragraph->get_alignment()) != 0)) {
 	  /*
 	   *  different alignment, so shutdown paragraph and open
 	   *  a new one.
@@ -2821,7 +2897,10 @@ void html_printer::do_check_center(void)
 	  int space = current_paragraph->retrieve_para_space() || seen_space;
 	  current_paragraph->done_para();
 	  supress_sub_sup = TRUE;
-	  current_paragraph->do_para("align=center", space);
+	  if (dialect == html4)
+	    current_paragraph->do_para("align=\"center\"", space);
+	  else
+	    current_paragraph->do_para("class=\"center\"", space);
 	} else
 	  /*
 	   *  same alignment, if we have emitted text then issue a break.
@@ -2898,7 +2977,10 @@ void html_printer::insert_split_file (void)
 
     split_file += string("-");
     split_file += as_string(header.no_of_level_one_headings);
-    split_file += string(".html");
+    if (dialect == xhtml)
+      split_file += string(".xhtml");
+    else
+      split_file += string(".html");
     split_file += '\0';
 
     file_list.set_file_name(split_file);
@@ -3092,9 +3174,15 @@ void html_printer::troff_tag (text_glob *g)
    *  firstly skip over devtag:
    */
   char *t=(char *)g->text_string+strlen("devtag:");
-
   if (strncmp(g->text_string, "html</p>:", strlen("html</p>:")) == 0) {
     do_end_para(g);
+  } else if (strncmp(g->text_string, "html<?p>:", strlen("html<?p>:")) == 0) {
+    if (current_paragraph->emitted_text())
+      html.put_string(g->text_string+9);
+    else
+      do_end_para(g);
+  } else if (strncmp(g->text_string, "math<?p>:", strlen("math<?p>:")) == 0) {
+    do_math(g);
   } else if (g->is_eol()) {
     do_eol();
   } else if (g->is_eol_ce()) {
@@ -3177,6 +3265,19 @@ void html_printer::troff_tag (text_glob *g)
 }
 
 /*
+ *  do_math - prints out the equation
+ */
+
+void html_printer::do_math (text_glob *g)
+{
+  do_font(g);
+  if (current_paragraph->emitted_text())
+    html.put_string(g->text_string+9);
+  else
+    do_end_para(g);
+}
+
+/*
  *  is_in_middle - returns TRUE if the positions left..right are in the center of the page.
  */
 
@@ -4720,7 +4821,10 @@ void html_printer::write_title (int in_head)
     } else {
       title.has_been_written = TRUE;
       if (title.with_h1) {
-	html.put_string("<h1 align=center>");
+	if (dialect == xhtml)
+	  html.put_string("<h1>");
+	else
+	  html.put_string("<h1 align=\"center\">");
 	html.put_string(title.text);
 	html.put_string("</h1>").nl().nl();
       }
@@ -4737,8 +4841,12 @@ void html_printer::write_title (int in_head)
 
 static void write_rule (void)
 {
-  if (auto_rule)
-    fputs("<hr>\n", stdout);
+  if (auto_rule) {
+    if (dialect == xhtml)
+      fputs("<hr/>\n", stdout);
+    else
+      fputs("<hr>\n", stdout);
+  }
 }
 
 void html_printer::begin_page(int n)
@@ -4757,7 +4865,7 @@ void html_printer::begin_page(int n)
   output_hpos            = -1;
   output_vpos            = -1;
   output_vpos_max        = -1;
-  current_paragraph      = new html_text(&html);
+  current_paragraph      = new html_text(&html, dialect);
   do_indent(get_troff_indent(), pageoffset, linelength);
   current_paragraph->do_para("", FALSE);
 }
@@ -4815,7 +4923,13 @@ void html_printer::write_navigation (const string &top, const string &prev,
   int need_bar = FALSE;
 
   if (multiple_files) {
+    current_paragraph->done_para();
     write_rule();
+    if (groff_sig)
+      fputs("\n\n<table width=\"100%\" border=\"0\" rules=\"none\"\n"
+	    "frame=\"void\" cellspacing=\"1\" cellpadding=\"0\">\n"
+	    "<colgroup><col class=\"left\"></col><col class=\"right\"></col></colgroup>\n"
+	    "<tr><td class=\"left\">", stdout);
     fputs("[ ", stdout);
     if ((strcmp(prev.contents(), "") != 0) && prev != top && prev != current) {
       emit_link(prev, "prev");
@@ -4833,6 +4947,16 @@ void html_printer::write_navigation (const string &top, const string &prev,
       emit_link(top, "top");
     }
     fputs(" ]\n", stdout);
+    handle_valid_flag();
+
+    if (groff_sig) {
+      fputs("</td><td class=\"right\"><i><small>"
+	    "This document was produced using "
+	    "<a href=\"http://www.gnu.org/software/groff/\">"
+	    "groff-", stdout);
+      fputs(Version_string, stdout);
+      fputs("</a>.</small></i></td></tr></table>\n", stdout);
+    }
     write_rule();
   }
 }
@@ -4857,7 +4981,10 @@ void html_printer::do_file_components (void)
 
   file_list.start_of_list();
   top = string(job_name);
-  top += string(".html");
+  if (dialect == xhtml)
+    top += string(".xhtml");
+  else
+    top += string(".html");
   top += '\0';
   next = file_list.next_file_name();
   next += '\0';
@@ -4870,6 +4997,12 @@ void html_printer::do_file_components (void)
     
     file_list.move_next();
     if (file_list.is_new_output_file()) {
+#ifdef LONG_FOR_TIME_T
+      long t;
+#else
+      time_t t;
+#endif
+
       if (fragment_no > 1)
 	write_navigation(top, prev, next, current);
       prev = current;
@@ -4881,7 +5014,27 @@ void html_printer::do_file_components (void)
       fflush(stdout);
       freopen(split_file.contents(), "w", stdout);
       fragment_no++;
-      writeHeadMetaStyle();
+      if (dialect == xhtml)
+	writeHeadMetaStyle();
+
+      html.begin_comment("Creator     : ")
+	.put_string("groff ")
+	.put_string("version ")
+	.put_string(Version_string)
+	.end_comment();
+
+      t = time(0);
+      html.begin_comment("CreationDate: ")
+	.put_string(ctime(&t), strlen(ctime(&t))-1)
+	.end_comment();
+
+      if (dialect == html4)
+	writeHeadMetaStyle();
+
+      html.put_string("<title>");
+      html.put_string(split_file.contents());
+      html.put_string("</title>").nl().nl();
+
       fputs(head_info.contents(), stdout);
       fputs("</head>\n", stdout);
       write_navigation(top, prev, next, current);
@@ -4891,8 +5044,27 @@ void html_printer::do_file_components (void)
   }
   if (fragment_no > 1)
     write_navigation(top, prev, next, current);
-  else
+  else {
+    current_paragraph->done_para();
     write_rule();
+    if (valid_flag && dialect == xhtml) {
+      if (groff_sig)
+	fputs("\n\n<table width=\"100%\" border=\"0\" rules=\"none\"\n"
+	      "frame=\"void\" cellspacing=\"1\" cellpadding=\"0\">\n"
+	      "<colgroup><col class=\"left\"></col><col class=\"right\"></col></colgroup>\n"
+	      "<tr><td class=\"left\">", stdout);
+      handle_valid_flag();
+      if (groff_sig) {
+	fputs("</td><td class=\"right\"><i><small>"
+	      "This document was produced using "
+	      "<a href=\"http://www.gnu.org/software/groff/\">"
+	      "groff-", stdout);
+	fputs(Version_string, stdout);
+	fputs("</a>.</small></i></td></tr></table>\n", stdout);
+      }
+      write_rule();
+    }
+  }
 }
 
 /*
@@ -4902,21 +5074,43 @@ void html_printer::do_file_components (void)
 
 void html_printer::writeHeadMetaStyle (void)
 {
-  fputs("<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\"\n", stdout);
-  fputs("\"http://www.w3.org/TR/html4/loose.dtd\">\n", stdout);
-
-  fputs("<html>\n", stdout);
-  fputs("<head>\n", stdout);
-  fputs("<meta name=\"generator\" "
-	      "content=\"groff -Thtml, see www.gnu.org\">\n", stdout);
-  fputs("<meta http-equiv=\"Content-Type\" "
-	      "content=\"text/html; charset=US-ASCII\">\n", stdout);
-  fputs("<meta name=\"Content-Style\" content=\"text/css\">\n", stdout);
-
-  fputs("<style type=\"text/css\">\n", stdout);
-  fputs("       p     { margin-top: 0; margin-bottom: 0; }\n", stdout);
-  fputs("       pre   { margin-top: 0; margin-bottom: 0; }\n", stdout);
-  fputs("       table { margin-top: 0; margin-bottom: 0; }\n", stdout);
+  if (dialect == html4) {
+    fputs("<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\"\n", stdout);
+    fputs("\"http://www.w3.org/TR/html4/loose.dtd\">\n", stdout);
+    fputs("<html>\n", stdout);
+    fputs("<head>\n", stdout);
+    fputs("<meta name=\"generator\" "
+	  "content=\"groff -Thtml, see www.gnu.org\">\n", stdout);
+    fputs("<meta http-equiv=\"Content-Type\" "
+	  "content=\"text/html; charset=US-ASCII\">\n", stdout);
+    fputs("<meta name=\"Content-Style\" content=\"text/css\">\n", stdout);
+    fputs("<style type=\"text/css\">\n", stdout);
+  }
+  else {
+    fputs("<?xml version=\"1.0\" encoding=\"us-ascii\"?>\n", stdout);
+    fputs("<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN\"\n", stdout);
+    fputs(" \"http://www.w3.org/TR/MathML2/dtd/xhtml-math11-f.dtd\"\n", stdout);
+    fputs(" [<!ENTITY mathml \"http://www.w3.org/1998/Math/MathML\">]>\n", stdout);
+
+    fputs("<html xmlns=\"http://www.w3.org/1999/xhtml\" xml:lang=\"en\">\n",
+	  stdout);
+    fputs("<head>\n", stdout);
+    fputs("<meta name=\"generator\" "
+	  "content=\"groff -Txhtml, see www.gnu.org\"/>\n", stdout);
+    fputs("<meta http-equiv=\"Content-Type\" "
+	  "content=\"text/html; charset=US-ASCII\"/>\n", stdout);
+    fputs("<meta name=\"Content-Style\" content=\"text/css\"/>\n", stdout);
+    fputs("<style type=\"text/css\">\n", stdout);
+    fputs("       .center { text-align: center }\n", stdout);
+    fputs("       .right  { text-align: right }\n", stdout);
+  }
+  fputs("       p       { margin-top: 0; margin-bottom: 0; "
+	"vertical-align=\"top\" }\n", stdout);
+  fputs("       pre     { margin-top: 0; margin-bottom: 0; "
+	"vertical-align=\"top\" }\n", stdout);
+  fputs("       table   { margin-top: 0; margin-bottom: 0; "
+	"vertical-align=\"top\" }\n", stdout);
+  fputs("       h1      { text-align: center }\n", stdout);
   fputs("</style>\n", stdout);
 }
 
@@ -4932,6 +5126,10 @@ html_printer::~html_printer()
     current_paragraph->flush_text();
   html.end_line();
   html.set_file(stdout);
+
+  if (dialect == xhtml)
+    writeHeadMetaStyle();
+
   html.begin_comment("Creator     : ")
     .put_string("groff ")
     .put_string("version ")
@@ -4943,7 +5141,8 @@ html_printer::~html_printer()
     .put_string(ctime(&t), strlen(ctime(&t))-1)
     .end_comment();
 
-  writeHeadMetaStyle();
+  if (dialect == html4)
+    writeHeadMetaStyle();
 
   write_title(TRUE);
   head_info += '\0';
@@ -5123,9 +5322,12 @@ void html_printer::special(char *s, const environment *env, char type)
        * requesting that the formatting move right by the appropriate
        * amount.
        */
-    } else if (strncmp(s, "html</p>:", 9) == 0) {
+    } else if ((strncmp(s, "html</p>:", 9) == 0) ||
+	       (strncmp(s, "html<?p>:", 9) == 0) ||
+	       (strncmp(s, "math<?p>:", 9) == 0)) {
       int r=font::res;   /* resolution of the device */
       font *f=sbuf_style.f;
+      string t;
 
       if (f == NULL) {
 	int found=FALSE;
@@ -5133,6 +5335,17 @@ void html_printer::special(char *s, const environment *env, char type)
 	f = font::load_font("TR", &found);
       }
 
+      if (strncmp(s, "math<?p>:", 9) == 0) {
+	if (strncmp((char *)&s[9], "<math>", 6) == 0) {
+	  s[9] = '\0';
+	  t = s;
+	  t += "<math xmlns=\"http://www.w3.org/1998/Math/MathML\">";
+	  t += (char *)&s[15];
+	  t += '\0';
+	  s = (char *)&t[0];
+	}
+      }
+
       /*
        *  need to pass all of string through to html output during flush
        */
@@ -5148,6 +5361,7 @@ void html_printer::special(char *s, const environment *env, char type)
        * requesting that the formatting move right by the appropriate
        * amount.
        */
+
     } else if (strncmp(s, "index:", 6) == 0) {
       cutoff_heading = atoi(&s[6]);
     } else if (strncmp(s, "assertion:[", 11) == 0) {
@@ -5211,6 +5425,21 @@ int html_printer::round_width(int x)
   return n * r;
 }
 
+/*
+ *  handle_valid_flag - emits a valid xhtml 1.1 button, provided -V and -x
+ *                      were supplied on the command line.
+ */
+
+void html_printer::handle_valid_flag (void)
+{
+  if (valid_flag && dialect == xhtml)
+    fputs("<p>"
+	  "<a href=\"http://validator.w3.org/check?uri=referer\"><img "
+	  "src=\"http://www.w3.org/Icons/valid-xhtml11\" "
+	  "alt=\"Valid XHTML 1.1 Transitional\" height=\"31\" width=\"88\" /></a>\n"
+	  "</p>\n", stdout);
+}
+
 int main(int argc, char **argv)
 {
   program_name = argv[0];
@@ -5222,7 +5451,7 @@ int main(int argc, char **argv)
     { "version", no_argument, 0, 'v' },
     { NULL, 0, 0, 0 }
   };
-  while ((c = getopt_long(argc, argv, "a:bdD:F:g:hi:I:j:lno:prs:S:v",
+  while ((c = getopt_long(argc, argv, "a:bdD:eF:g:hi:I:j:lno:prs:S:vVx:y",
 			  long_options, NULL))
 	 != EOF)
     switch(c) {
@@ -5240,6 +5469,9 @@ int main(int argc, char **argv)
     case 'D':
       /* handled by pre-html */
       break;
+    case 'e':
+      /* handled by pre-html */
+      break;
     case 'F':
       font::command_line_font_dir(optarg);
       break;
@@ -5285,6 +5517,21 @@ int main(int argc, char **argv)
       printf("GNU post-grohtml (groff) version %s\n", Version_string);
       exit(0);
       break;
+    case 'V':
+      valid_flag = TRUE;
+      break;
+    case 'x':
+      if (strcmp(optarg, "x") == 0) {
+	dialect = xhtml;
+	simple_anchors = TRUE;
+      } else if (strcmp(optarg, "4") == 0)
+	dialect = html4;
+      else
+	printf("unsupported html dialect %s (defaulting to html4)\n", optarg);
+      break;
+    case 'y':
+      groff_sig = TRUE;
+      break;
     case CHAR_MAX + 1: // --help
       usage(stdout);
       exit(0);
@@ -5307,6 +5554,6 @@ int main(int argc, char **argv)
 
 static void usage(FILE *stream)
 {
-  fprintf(stream, "usage: %s [-vblnh] [-D dir] [-I image_stem] [-F dir] [files ...]\n",
+  fprintf(stream, "usage: %s [-vbelnhVy] [-D dir] [-I image_stem] [-F dir] [-x x] [files ...]\n",
 	  program_name);
 }