Fixing a bug which prevented hyphenation in words followed

immediately by a TOKEN_NODE (e.g. ` ', `~', etc.).

* src/roff/troff/input.cc (process_input_stack <token::TOKEN_NODE>):
Adding possibly_break_line().
* src/roff/troff/env.h (environment): Make possibly_break_line()
public.

Make `~' usable in .tr request.

* src/roff/troff/token.h (token_type): Add TOKEN_STRETCHABLE_SPACE.
(token): Add stretchable_space().
* src/roff/troff/input.cc (token::next, token::delimiter,
token::description, process_input_stack, do_translate,
add_to_node_list, token::process): Use it.
* src/roff/troff/node.h (node): Add fourth parameter to add_char()
for adjusting the space.
* src/roff/troff/node.cc (node::add_char): Implement it.  Add code
for stretchable space.
* src/roff/troff/input.cc (token::add_to_node_list): Use it.
(make_node): Add code for stretchable space.
* src/roff/troff/env.cc (environment::add_char): Use it.
* src/roff/troff/input.cc: Add ESCAPE_TILDE special character.
(get_copy, token::next, transparent_translate, asciify): Use it.

* NEWS, src/roff/troff/troff.man, src/roff/troff/TODO,
doc/groff.texinfo: Updated.
* man/groff.man: Small reorderings.

12 files changed, 218 insertions, 91 deletions

diff --git a/ChangeLog b/ChangeLog
index 36fca847..8d4789dc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,34 @@
+2000-12-02  Werner LEMBERG  <wl@gnu.org>
+
+	Fixing a bug which prevented hyphenation in words followed
+	immediately by a TOKEN_NODE (e.g. `\ ', `\~', etc.).
+
+	* src/roff/troff/input.cc (process_input_stack <token::TOKEN_NODE>):
+	Adding possibly_break_line().
+	* src/roff/troff/env.h (environment): Make possibly_break_line()
+	public.
+
+	Make `\~' usable in .tr request.
+
+	* src/roff/troff/token.h (token_type): Add TOKEN_STRETCHABLE_SPACE.
+	(token): Add stretchable_space().
+	* src/roff/troff/input.cc (token::next, token::delimiter,
+	token::description, process_input_stack, do_translate,
+	add_to_node_list, token::process): Use it.
+	* src/roff/troff/node.h (node): Add fourth parameter to add_char()
+	for adjusting the space.
+	* src/roff/troff/node.cc (node::add_char): Implement it.  Add code
+	for stretchable space.
+	* src/roff/troff/input.cc (token::add_to_node_list): Use it.
+	(make_node): Add code for stretchable space.
+	* src/roff/troff/env.cc (environment::add_char): Use it.
+	* src/roff/troff/input.cc: Add ESCAPE_TILDE special character.
+	(get_copy, token::next, transparent_translate, asciify): Use it.
+
+	* NEWS, src/roff/troff/troff.man, src/roff/troff/TODO,
+	doc/groff.texinfo: Updated.
+	* man/groff.man: Small reorderings.
+
 2000-11-23  Werner LEMBERG  <wl@gnu.org>
 
 	* NEWS: Fixes.
diff --git a/NEWS b/NEWS
index 07e8d9b8..34b4e783 100644
--- a/NEWS
+++ b/NEWS
@@ -4,50 +4,52 @@ are not described.  There are more details in the man pages.
 Groff
 -----
 
-`-mFOO' will now search first for `FOO.tmac' and then for `tmac.FOO'.  The
-old behaviour has been changed to overcome problems with platforms which
-have an 8+3 file name limit, and platforms which have other versions of
-troff installed also.  Additionally, all macro files have been renamed
-using the latter scheme to avoid 8+3 name clashes.
-
-The new environment variable GROFF_BIN_PATH will be checked for programs
-groff is calling (preprocessors, troff, and output devices) before PATH.  If
-not set, it defaults to the directory where the groff binary is located.
-Previously, it was PATH only.  The nroff script will only use GROFF_BIN_PATH
-to find the groff binary but passes both the GROFF_BIN_PATH and PATH
-environment variable to groff.
+o `-mFOO' will now search first for `FOO.tmac' and then for `tmac.FOO'.  The
+  old behaviour has been changed to overcome problems with platforms which
+  have an 8+3 file name limit, and platforms which have other versions of
+  troff installed also. Additionally, all macro files have been renamed
+  using the latter scheme to avoid 8+3 name clashes.
+
+o The new environment variable GROFF_BIN_PATH will be checked for programs
+  groff is calling (preprocessors, troff, and output devices) before PATH. 
+  If not set, it defaults to the directory where the groff binary is
+  located.  Previously, it was PATH only.  The nroff script will only use
+  GROFF_BIN_PATH to find the groff binary but passes both the GROFF_BIN_PATH
+  and PATH environment variable to groff.
 
 Troff
 -----
 
-A new request `nop' (no operation) has been added which is similar to
-`if 1'.  For example,
+o A new request `nop' (no operation) has been added which is similar to
+  `if 1'.  For example,
 
-.if t \{\
-Hallo!
-.\}
+    .if t \{\
+    Hallo!
+    .\}
 
-can now be written as
+  can now be written as
 
-.if t \{\
-.  nop Hallo!
-.\}
+    .if t \{\
+    .  nop Hallo!
+    .\}
 
-Two new requests `tm1' and `tmc' have been added to improve writing messages
-to the terminal.  `tm1' is similar to `tm' but allows leading whitespace.
-`tmc' is similar to `tm1' but doesn't emit a final newline.
+o Two new requests `tm1' and `tmc' have been added to improve writing
+  messages to the terminal.  `tm1' is similar to `tm' but allows leading
+  whitespace.  `tmc' is similar to `tm1' but doesn't emit a final newline.
 
-A new request `dei' (define indirect) has been added.  The first and second
-parameter of `dei' are taken from string registers instead directly; this
-very special request is needed to make `trace.tmac' independent from the
-escape character (which might even be disabled).
+o A new request `dei' (define indirect) has been added.  The first and
+  second parameter of `dei' are taken from string registers rather than
+  directly; this very special request is needed to make `trace.tmac'
+  independent from the escape character (which might even be disabled).
 
-It is now possible to save and restore the escape character with two new
-requests `ecs' and `ecr'.
+o It is now possible to save and restore the escape character with two new
+  requests `ecs' and `ecr'.
 
-The new escape sequence \B'...' is an analogon to `\A': If the string within
-the delimiters is a valid numeric expression, return character `1', and `0'
-otherwise.
+o The new escape sequence \B'...' is an analogon to `\A': If the string
+  within the delimiters is a valid numeric expression, return character `1',
+  and `0' otherwise.
+
+o The `tr' request can now map characters onto `\~'.
 
 Nroff
 -----
@@ -57,10 +59,10 @@ Option -v shows the version number.
 Grog
 ----
 
-The grog script will now work in non-compatibility mode also (which is the
-default).  As usual, use the `-C' option to activate compatibility mode.
+o The grog script will now work in non-compatibility mode also (which is the
+  default).  As usual, use the `-C' option to activate compatibility mode.
 
-Option -v shows the version number.
+o Option -v shows the version number.
 
 Grops
 -----
@@ -71,7 +73,7 @@ added to select a different prologue file.
 Miscellaneous
 -------------
 
-For security reasons the following changes have been done:
+o For security reasons the following changes have been done:
 
   . The tmac.safer file has been replaced with a built-in solution; .open,
     .opena, .pso, .sy, and .pi are completely disabled in safer mode (which
@@ -93,15 +95,16 @@ For security reasons the following changes have been done:
     Use the `-F' command line option or the GROFF_FONT_PATH environment
     variable if you really need the current directory.
 
-groff will now install its data files into /usr/local/share/groff/<version>
-by default, following the GNU standard.  Additionally, a local tmac
-directory (by default /usr/local/share/groff/site-tmac) will be scanned
-before the standard tmac directory.  Wrapper files for system-specific macro
-packages (if necessary) are put into /usr/local/lib/groff/site-tmac; this
-directory will be searched before the local tmac directory.
+o groff will now install its data files into
+  /usr/local/share/groff/<version> by default, following the GNU standard. 
+  Additionally, a local tmac directory (by default
+  /usr/local/share/groff/site-tmac) will be scanned before the standard tmac
+  directory.  Wrapper files for system-specific macro packages (if
+  necessary) are put into /usr/local/lib/groff/site-tmac; this directory
+  will be searched before the local tmac directory.
 
-All programs now have option `-v' to show the version number; they will exit
-immediately afterwards, following the GNU standards.
+o All programs now have option `-v' to show the version number; they will
+  exit immediately afterwards, following the GNU standards.
 
 VERSION 1.16.1
 ==============
diff --git a/doc/groff.texinfo b/doc/groff.texinfo
index 03393cec..c5c46432 100644
--- a/doc/groff.texinfo
+++ b/doc/groff.texinfo
@@ -4737,8 +4737,9 @@ The @code{\e} escape can be translated also.
 
 @item
 @findex \%
-Characters can be mapped onto the @code{\%} escape (but @code{\%} can't
-be mapped onto another character).
+@findex \~
+Characters can be mapped onto the @code{\%} and @code{\~} escapes (but
+@code{\%} and @code{\~} can't be mapped onto another character).
 
 @item
 @cindex backspace character
@@ -6354,7 +6355,7 @@ name.
 This would be called as
 
 @example
-.vl $Id: groff.texinfo,v 1.55 2000/11/15 22:29:39 wlemb Exp $
+.vl $Id: groff.texinfo,v 1.56 2000/12/02 21:18:02 wlemb Exp $
 @end example
 
 @xref{Request Arguments}.
diff --git a/man/groff.man b/man/groff.man
index 3f46621c..98e8f030 100644
--- a/man/groff.man
+++ b/man/groff.man
@@ -1057,13 +1057,13 @@ Reset escape character to
 Set escape character to
 .argument c .
 .
-.REQ .ecs
-Save current escape character.
-.
 .REQ .ecr
 Restore escape character saved with
 .request .ecs .
 .
+.REQ .ecs
+Save current escape character.
+.
 .REQ .el anything
 Else part for if-else (\c
 .argument .ie )
@@ -1628,10 +1628,6 @@ Enable track kerning for
 .REQ .tl \f(CB\(cq\fPleft\f(CB\(cq\fPcenter\f(CB\(cq\fPright\f(CB\(cq\fP
 Three-part title.
 .
-.REQ .trf filename
-Transparently output the contents of file
-.argument filename .
-.
 .REQ .tm anything
 Print
 .argument anything
@@ -1661,6 +1657,10 @@ to
 .argument d ,
 etc. on output.
 .
+.REQ .trf filename
+Transparently output the contents of file
+.argument filename .
+.
 .REQ .trnt abcd....
 This is the same as the
 .request .tr
diff --git a/src/roff/troff/TODO b/src/roff/troff/TODO
index 6fd50ff3..79d84e29 100644
--- a/src/roff/troff/TODO
+++ b/src/roff/troff/TODO
@@ -24,7 +24,7 @@ decision of where to break the line.
 Provide a mechanism to control the shape of the rag in non-justified
 text.
 
-Add a discretionary break escape sequence. \B'...'...'...' like TeX.
+Add a discretionary break escape sequence. \='...'...'...' like TeX.
 
 Think about kerning between characters and spaces. (Need to implement
 get_breakpoints and split methods for kern_pair_node class.)
@@ -40,8 +40,6 @@ and has a non-zero hyphen-type. Then we ought to be able to hyphenate,
 but we won't be able to because we will look for the hyphen only in
 font S and not in font R.
 
-Variant of tm which doesn't write a newline.
-
 Perhaps the current input level should be accessible in a number register.
 
 Should \w deal with a newline like \X?
@@ -124,8 +122,6 @@ decrement when it's at the same input level as the request.
 Don't ever change a charinfo.  Create new variants instead and chain
 them together.
 
-Make it possible to tr characters onto \~.
-
 Unix troff appears to read the first character of a request name in
 copy mode.  Should we do the same?
 
diff --git a/src/roff/troff/env.cc b/src/roff/troff/env.cc
index 378cfffd..b65742d3 100644
--- a/src/roff/troff/env.cc
+++ b/src/roff/troff/env.cc
@@ -260,6 +260,7 @@ void leader_character()
 
 void environment::add_char(charinfo *ci)
 {
+  int s;
   if (interrupted)
     ;
   // don't allow fields in dummy environments
@@ -275,7 +276,7 @@ void environment::add_char(charinfo *ci)
     if (tab_contents == 0)
       tab_contents = new line_start_node;
     if (ci != hyphen_indicator_char)
-      tab_contents = tab_contents->add_char(ci, this, &tab_width);
+      tab_contents = tab_contents->add_char(ci, this, &tab_width, &s);
     else
       tab_contents = tab_contents->add_discretionary_hyphen();
   }
@@ -283,7 +284,7 @@ void environment::add_char(charinfo *ci)
     if (line == 0)
       start_line();
     if (ci != hyphen_indicator_char)
-      line = line->add_char(ci, this, &width_total);
+      line = line->add_char(ci, this, &width_total, &space_total);
     else
       line = line->add_discretionary_hyphen();
   }
diff --git a/src/roff/troff/env.h b/src/roff/troff/env.h
index 6792ea63..74f23cae 100644
--- a/src/roff/troff/env.h
+++ b/src/roff/troff/env.h
@@ -189,7 +189,6 @@ class environment {
 #ifdef WIDOW_CONTROL
   void mark_last_line();
 #endif /* WIDOW_CONTROL */
-  void possibly_break_line(int forced = 0);
   breakpoint *choose_breakpoint();
   void hyphenate_line();
   void start_field();
@@ -268,6 +267,7 @@ public:
   void set_input_line_position(hunits);	// used by \n(hp
   void interrupt();
   void spread() { spread_flag = 1; }
+  void possibly_break_line(int forced = 0);
   void do_break();			// .br
   void final_break();
   void add_html_tag (const char *name);
diff --git a/src/roff/troff/input.cc b/src/roff/troff/input.cc
index c0661913..f11b5a98 100644
--- a/src/roff/troff/input.cc
+++ b/src/roff/troff/input.cc
@@ -172,6 +172,7 @@ const int VJUSTIFY_REQUEST = 0203;
 const int ESCAPE_E = 0204;
 const int LAST_PAGE_EJECTOR = 0205;
 const int ESCAPE_RIGHT_PARENTHESIS = 0206;
+const int ESCAPE_TILDE = 0207;
 
 #else /* IS_EBCDIC_HOST */
 
@@ -204,6 +205,7 @@ const int VJUSTIFY_REQUEST = 063;
 const int ESCAPE_E = 064;
 const int LAST_PAGE_EJECTOR = 065;
 const int ESCAPE_RIGHT_PARENTHESIS = 066;
+const int ESCAPE_TILDE = 067;
 
 #endif /* IS_EBCDIC_HOST */
 
@@ -909,6 +911,9 @@ static int get_copy(node **nd, int defining)
     case ' ':
       (void)input_stack::get(NULL);
       return ESCAPE_SPACE;
+    case '~':
+      (void)input_stack::get(NULL);
+      return ESCAPE_TILDE;
     case '|':
       (void)input_stack::get(NULL);
       return ESCAPE_BAR;
@@ -1315,6 +1320,11 @@ void token::next()
 	type = TOKEN_NODE;
 	nd = new space_char_hmotion_node(curenv->get_space_width());
 	return;
+      case ESCAPE_TILDE:
+      ESCAPE_TILDE:
+	type = TOKEN_STRETCHABLE_SPACE;
+	nd = new unbreakable_space_node(curenv->get_space_width());
+	return;
       case ESCAPE_e:
       ESCAPE_e:
 	type = TOKEN_ESCAPE;
@@ -1469,9 +1479,7 @@ void token::next()
       case '?':
 	goto ESCAPE_QUESTION;
       case '~':
-	nd = new unbreakable_space_node(curenv->get_space_width());
-	type = TOKEN_NODE;
-	return;
+	goto ESCAPE_TILDE;
       case '"':
 	while ((cc = input_stack::get(NULL)) != '\n' && cc != EOF)
 	  ;
@@ -1786,6 +1794,7 @@ int token::delimiter(int err)
     }
   case TOKEN_NODE:
   case TOKEN_SPACE:
+  case TOKEN_STRETCHABLE_SPACE:
   case TOKEN_TAB:
   case TOKEN_NEWLINE:
     if (err)
@@ -1834,6 +1843,8 @@ const char *token::description()
     return "`\\}'";
   case TOKEN_SPACE:
     return "a space";
+  case TOKEN_STRETCHABLE_SPACE:
+    return "`\\~'";
   case TOKEN_SPECIAL:
     return "a special character";
   case TOKEN_SPREAD:
@@ -2059,6 +2070,8 @@ static int transparent_translate(int cc)
     switch (ci->get_special_translation(1)) {
     case charinfo::TRANSLATE_SPACE:
       return ' ';
+    case charinfo::TRANSLATE_STRETCHABLE_SPACE:
+      return ESCAPE_TILDE;
     case charinfo::TRANSLATE_DUMMY:
       return ESCAPE_AMPERSAND;
     case charinfo::TRANSLATE_HYPHEN_INDICATOR:
@@ -2281,6 +2294,7 @@ void process_input_stack()
     case token::TOKEN_EOF:
       return;
     case token::TOKEN_NODE:
+    case token::TOKEN_STRETCHABLE_SPACE:
       {
 	if (possibly_handle_first_page_transition())
 	  ;
@@ -2292,6 +2306,7 @@ void process_input_stack()
 	  curenv->add_node(tok.nd);
 	  tok.nd = 0;
 	  bol = 0;
+	  curenv->possibly_break_line();
 	}
 	break;
       }
@@ -4798,6 +4813,9 @@ const char *asciify(int c)
   case ESCAPE_SPACE:
     buf[1] = ' ';
     break;
+  case ESCAPE_TILDE:
+    buf[1] = '~';
+    break;
   default:
     if (illegal_input_char(c))
       buf[0] = '\0';
@@ -5036,8 +5054,7 @@ static void init_charset_table()
   page_character = charset_table['%'];
 }
 
-static
-void do_translate(int translate_transparent)
+static void do_translate(int translate_transparent)
 {
   tok.skip();
   while (!tok.newline() && !tok.eof()) {
@@ -5062,6 +5079,9 @@ void do_translate(int translate_transparent)
     if (tok.space())
       ci1->set_special_translation(charinfo::TRANSLATE_SPACE,
 				   translate_transparent);
+    else if (tok.stretchable_space())
+      ci1->set_special_translation(charinfo::TRANSLATE_STRETCHABLE_SPACE,
+				   translate_transparent);
     else if (tok.dummy())
       ci1->set_special_translation(charinfo::TRANSLATE_DUMMY,
 				   translate_transparent);
@@ -5182,17 +5202,18 @@ void check_missing_character()
 int token::add_to_node_list(node **pp)
 {
   hunits w;
+  int s;
   node *n = 0;
   switch (type) {
   case TOKEN_CHAR:
-    *pp = (*pp)->add_char(charset_table[c], curenv, &w);
+    *pp = (*pp)->add_char(charset_table[c], curenv, &w, &s);
     break;
   case TOKEN_DUMMY:
     n = new dummy_node;
     break;
   case TOKEN_ESCAPE:
     if (escape_char != 0)
-      *pp = (*pp)->add_char(charset_table[escape_char], curenv, &w);
+      *pp = (*pp)->add_char(charset_table[escape_char], curenv, &w, &s);
     break;
   case TOKEN_HYPHEN_INDICATOR:
     *pp = (*pp)->add_discretionary_hyphen();
@@ -5206,11 +5227,12 @@ int token::add_to_node_list(node **pp)
     set_number_reg(nm, curenv->get_input_line_position().to_units());
     break;
   case TOKEN_NODE:
+  case TOKEN_STRETCHABLE_SPACE:
     n = nd;
     nd = 0;
     break;
   case TOKEN_NUMBERED_CHAR:
-    *pp = (*pp)->add_char(get_charinfo_by_number(val), curenv, &w);
+    *pp = (*pp)->add_char(get_charinfo_by_number(val), curenv, &w, &s);
     break;
   case TOKEN_RIGHT_BRACE:
     break;
@@ -5218,7 +5240,7 @@ int token::add_to_node_list(node **pp)
     n = new hmotion_node(curenv->get_space_width());
     break;
   case TOKEN_SPECIAL:
-    *pp = (*pp)->add_char(get_charinfo(nm), curenv, &w);
+    *pp = (*pp)->add_char(get_charinfo(nm), curenv, &w, &s);
     break;
   default:
     return 0;
@@ -5280,6 +5302,7 @@ void token::process()
     curenv->newline();
     break;
   case TOKEN_NODE:
+  case TOKEN_STRETCHABLE_SPACE:
     curenv->add_node(nd);
     nd = 0;
     break;
diff --git a/src/roff/troff/node.cc b/src/roff/troff/node.cc
index f5585512..580785ab 100644
--- a/src/roff/troff/node.cc
+++ b/src/roff/troff/node.cc
@@ -3877,6 +3877,8 @@ node *make_node(charinfo *ci, environment *env)
   switch (ci->get_special_translation()) {
   case charinfo::TRANSLATE_SPACE:
     return new space_char_hmotion_node(env->get_space_width());
+  case charinfo::TRANSLATE_STRETCHABLE_SPACE:
+    return new unbreakable_space_node(env->get_space_width());
   case charinfo::TRANSLATE_DUMMY:
     return new dummy_node;
   case charinfo::TRANSLATE_HYPHEN_INDICATOR:
@@ -3910,7 +3912,8 @@ int character_exists(charinfo *ci, environment *env)
   return 0;
 }
 
-node *node::add_char(charinfo *ci, environment *env, hunits *widthp)
+node *node::add_char(charinfo *ci, environment *env,
+		     hunits *widthp, int *spacep)
 {
   node *res;
   switch (ci->get_special_translation()) {
@@ -3918,6 +3921,11 @@ node *node::add_char(charinfo *ci, environment *env, hunits *widthp)
     res = new space_char_hmotion_node(env->get_space_width(), this);
     *widthp += res->width();
     return res;
+  case charinfo::TRANSLATE_STRETCHABLE_SPACE:
+    res = new unbreakable_space_node(env->get_space_width(), this);
+    *widthp += res->width();
+    *spacep += res->nspaces();
+    return res;
   case charinfo::TRANSLATE_DUMMY:
     return new dummy_node(this);
   case charinfo::TRANSLATE_HYPHEN_INDICATOR:
diff --git a/src/roff/troff/node.h b/src/roff/troff/node.h
index 6a602dc3..9dc05308 100644
--- a/src/roff/troff/node.h
+++ b/src/roff/troff/node.h
@@ -52,7 +52,7 @@ struct node {
   node *last;
   node();
   node(node *n);
-  node *add_char(charinfo *c, environment *, hunits *widthp);
+  node *add_char(charinfo *c, environment *, hunits *widthp, int *spacep);
 
   virtual ~node();
   virtual node *copy() = 0;
diff --git a/src/roff/troff/token.h b/src/roff/troff/token.h
index f6707f2a..0bcb72c7 100644
--- a/src/roff/troff/token.h
+++ b/src/roff/troff/token.h
@@ -1,5 +1,5 @@
 // -*- C++ -*-
-/* Copyright (C) 1989, 1990, 1991, 1992 Free Software Foundation, Inc.
+/* Copyright (C) 1989, 1990, 1991, 1992, 2000 Free Software Foundation, Inc.
      Written by James Clark (jjc@jclark.com)
 
 This file is part of groff.
@@ -50,6 +50,7 @@ class token {
     TOKEN_REQUEST,
     TOKEN_RIGHT_BRACE,
     TOKEN_SPACE,		// ` ' -- ordinary space
+    TOKEN_STRETCHABLE_SPACE,	// \~
     TOKEN_SPECIAL,		// a special character -- \' \` \- \(xx
     TOKEN_SPREAD,		// \p -- break and spread output line 
     TOKEN_TAB,			// tab
@@ -66,7 +67,8 @@ public:
   void skip();
   int eof();
   int nspaces();		// 1 if space, 2 if double space, 0 otherwise
-  int space();			// is it a space or double space?
+  int space();			// is the current token a space?
+  int stretchable_space();	// is the current token a stretchable space?
   int white_space();		// is the current token space or tab?
   int special();                // is the current token a special character?
   int newline();		// is the current token a newline?
@@ -125,6 +127,11 @@ inline int token::space()
   return type == TOKEN_SPACE;
 }
 
+inline int token::stretchable_space()
+{
+  return type == TOKEN_STRETCHABLE_SPACE;
+}
+
 inline int token::special()
 { 
   return type == TOKEN_SPECIAL;
diff --git a/src/roff/troff/troff.man b/src/roff/troff/troff.man
index d266317b..6a20049b 100644
--- a/src/roff/troff/troff.man
+++ b/src/roff/troff/troff.man
@@ -34,9 +34,17 @@ the original English.
 .\" so use \(ts instead of ".
 .tr \(ts"
 .TH @G@TROFF @MAN1EXT@ "@MDATE@" "Groff Version @VERSION@"
+.
+.
 .SH NAME
+.
+.
 @g@troff \- format documents
+.
+.
 .SH SYNOPSIS
+.
+.
 .nr a \n(.j
 .ad l
 .nr i \n(.i
@@ -65,15 +73,23 @@ the original English.
 .PP
 It is possible to have whitespace between a command line option and its
 parameter.
+.
+.
 .SH DESCRIPTION
+.
+.
 This manual page describes the GNU version of
 .BR troff ,
 which is part of the groff document formatting system.
-It is highly compatible with Unix troff.
+It is highly compatible with UNIX troff.
 Usually it should be invoked using the groff command, which will
 also run preprocessors and postprocessors in the appropriate
 order and with the appropriate options.
+.
+.
 .SH OPTIONS
+.
+.
 .TP \w'\-dname=s'u+2n
 .B \-a
 Generate an
@@ -236,9 +252,15 @@ Search directory (or directory path)
 .I dir
 for macro files.
 This is scanned before all other macro directories.
+.
+.
 .SH USAGE
-Only the features not in Unix troff are described here.
+.
+.
+Only the features not in UNIX troff are described here.
+.
 .SS Long names
+.
 The names of number registers, fonts, strings/macros/diversions,
 special characters can be of any length. In escape sequences, where
 you can use 
@@ -262,7 +284,9 @@ Interpolate string
 .BI \en[ xxx ]
 Interpolate number register
 .IR xxx .
+.
 .SS Fractional pointsizes
+.
 A
 .I
 scaled point
@@ -345,7 +369,9 @@ Be sure not to confuse the
 and
 .B z
 scale indicators.
+.
 .SS Numeric expressions
+.
 .LP
 Spaces are permitted in a number expression within parentheses.
 .LP
@@ -374,7 +400,9 @@ If
 .I c
 is missing, ignore scaling indicators in the evaluation of
 .IR e .
+.
 .SS New escape sequences
+.
 .TP
 .BI \eA' anything '
 This expands to
@@ -528,7 +556,7 @@ to have been defined as a macro and thus contain newlines
 (it is not permitted for the argument to
 .B \eX
 to contain newlines).
-The inclusion of newlines requires an extension to the Unix troff output
+The inclusion of newlines requires an extension to the UNIX troff output
 format, and will confuse drivers that do not know about this
 extension.
 .TP
@@ -559,7 +587,7 @@ In a macro, this gives the
 or
 .IR nnn -th
 argument.
-Macros can have a unlimited number of arguments.
+Macros can have an unlimited number of arguments.
 .TP
 .BI \e? anything \e?
 When used in a diversion, this will transparently embed
@@ -659,7 +687,9 @@ This is like
 except that
 .B \e"
 does not ignore the terminating newline.
+.
 .SS New requests
+.
 .TP
 .BI .aln\  xx\ yy
 Create an alias
@@ -1422,7 +1452,7 @@ transparently throughput into a diversion with
 .BR \e! .
 For example,
 .RS
-.LP
+.IP
 .nf
 .ft B
 \&.tr ab
@@ -1521,14 +1551,16 @@ is read in copy mode;
 a leading
 .B \(ts
 will be stripped.
+.
 .SS Extended requests
+.
 .TP
 .BI .cf\  filename
 When used in a diversion, this will embed in the diversion an object which,
 when reread, will cause the contents of
 .I filename
 to be transparently copied through to the output.
-In Unix troff, the
+In UNIX troff, the
 contents of
 .I filename
 is immediately copied through to the output regardless of whether
@@ -1574,11 +1606,11 @@ if the end of a sentence occurs at the end of a line in fill mode, then
 both an inter-word space and a sentence space will be added;
 if two spaces follow the end of a sentence in the middle of a line,
 then the second space will be a sentence space.
-Note that the behaviour of Unix troff will be exactly
+Note that the behaviour of UNIX troff will be exactly
 that exhibited by GNU troff if a second argument is never given to the
 .B ss
 request.
-In GNU troff, as in Unix troff, you should always
+In GNU troff, as in UNIX troff, you should always
 follow a sentence with either a newline or two spaces.
 .TP
 .BI .ta\  n1\ n2\|.\|.\|.nn \ T\  r1\ r2\|.\|.\|.\|rn
@@ -1603,7 +1635,9 @@ For example,
 .LP
 will set tabs every half an inch.
 .RE
+.
 .SS New number registers
+.
 The following read-only registers are available:
 .TP
 .B \en[.C]
@@ -1840,7 +1874,9 @@ Note that the traditional
 number register
 .B \en(yr
 is the current year minus 1900.
+.
 .SS Miscellaneous
+.
 .B @g@troff
 predefines a single (read/write) string-based register,
 .BR \e*(.T ,
@@ -1857,7 +1893,7 @@ which is defined to be\ 1 if
 is called with the
 .B -T
 command line option, and zero otherwise.  This behaviour is different to
-Unix troff.
+UNIX troff.
 .LP
 Fonts not listed in the
 .SM DESC
@@ -1947,7 +1983,14 @@ the condition will also be true if
 has been defined by the
 .B char
 request.
+.LP
+The
+.B tr
+request can now map characters onto
+.BR \e~ .
+.
 .SS Warnings
+.
 The warnings that can be given by
 .B troff
 are divided into the following categories.
@@ -2073,10 +2116,12 @@ that are useful with traditional macro packages.
 .TP
 .B w
 All warnings.
+.
 .SS Incompatibilities
+.
 .LP
 Long names cause some incompatibilities.
-Unix troff will interpret
+UNIX troff will interpret
 .IP
 .B
 \&.dsabcd
@@ -2087,7 +2132,7 @@ with contents
 .BR cd .
 Normally, GNU troff will interpret this as a call of a macro named
 .BR dsabcd .
-Also Unix troff will interpret
+Also UNIX troff will interpret
 .B \e*[
 or
 .B \en[
@@ -2112,14 +2157,14 @@ GNU troff
 does not allow the use of the escape sequences
 .BR \\e\e|\e^\e&\e}\e{\e (space) \e'\e`\e-\e_\e!\e%\ec
 in names of strings, macros, diversions, number registers,
-fonts or environments; Unix troff does.
+fonts or environments; UNIX troff does.
 The
 .B \eA
 escape sequence may be helpful in avoiding use of these
 escape sequences in names.
 .LP
 Fractional pointsizes cause one noteworthy incompatibility.
-In Unix troff the
+In UNIX troff the
 .B ps 
 request ignores scale indicators and so
 .IP
@@ -2173,7 +2218,7 @@ is turned into one output
 and the resulting output
 .BR \e s
 are not interpreted as escape characters when they are reread.
-Unix troff would interpret them as escape characters
+UNIX troff would interpret them as escape characters
 when they were reread and would end up printing one
 .BR \e .
 The correct way to obtain a printable
@@ -2182,7 +2227,7 @@ is to use the
 .B \ee
 escape sequence: this will always print a single instance of the
 current escape character, regardless of whether or not it is used in a
-diversion; it will also work in both GNU troff and Unix troff.
+diversion; it will also work in both GNU troff and UNIX troff.
 If you wish for some reason to store in a diversion an escape
 sequence that will be interpreted when the diversion is reread,
 you can either use the traditional
@@ -2190,7 +2235,11 @@ you can either use the traditional
 transparent output facility, or, if this is unsuitable, the new
 .B \e?
 escape sequence.
+.
+.
 .SH ENVIRONMENT
+.
+.
 .TP
 .SM
 .B GROFF_TMAC_PATH
@@ -2222,7 +2271,11 @@ will scan directories given in the
 option before these, and in standard directories
 .RB ( @FONTPATH@ )
 after these.
+.
+.
 .SH FILES
+.
+.
 .Tp \w'@FONTDIR@/devname/DESC'u+3n
 .B @MACRODIR@/troffrc
 Initialization file (called before any other macro package).
@@ -2259,7 +2312,11 @@ command line option or the
 .B GROFF_MACRO_PATH
 environment variable to add these directories to the search path if
 necessary.
+.
+.
 .SH "SEE ALSO"
+.
+.
 .BR groff (@MAN1EXT@),
 .BR @g@tbl (@MAN1EXT@),
 .BR @g@pic (@MAN1EXT@),