Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!umich!samsung!usc!sdsu!crash!pnet01!cwr
From: cwr@pnet01.cts.com (Will Rose)
Newsgroups: comp.os.minix
Subject: PC MINIX 1.5.0 nroff/roff
Message-ID: <1448@crash.cts.com>
Date: 12 Feb 90 02:36:01 GMT
Sender: root@crash.cts.com
Organization: People-Net [pnet01], El Cajon CA
Lines: 129

I've been looking at the roff version recently posted to this group by
by R Hall, and comparing it with the nroff in the 1.5.0 distribution.  One
problem is that I don't have a definitive guide to the 'real' nroff, so I'm
not clear as to what is an extension, and what is a standard feature.
 
Although nroff blows up with a shower of error messages when compiled as
distributed, the cure is simple - change the variable i in line 176 of
main.c from a long to an int.  It then compiles with two pointer warnings
in macros.c, and seems to work as intended.  One difficulty with this
version is that it includes a fair amount of atari-specific code for eg:
a VT52 terminal emulation, and a lot of atari screen specific escape
characters.  I personally prefer roff's approach of post-processors to
translate a series of standard escapes into sequences suitable for each
specific piece of hardware.  Can some expert say which approach fits
better with the standard Unix method (whatever that is)?
 
As far as features are concerned, both nroff and roff have useful things
the other lacks.  Nroff has many more escape codes, but these are highly
atari-specific; it also has the ability to redirect nroff error messages 
to a file, and accepts the - option to take input from stdin.  The one
capability nroff has that roff badly needs is the -m option, which reads
macro libraries from the standard directory /usr/lib/tmac.
 
Roff implements a diversion trap for endnotes, but not a witholding trap
for footnotes.  I don't know how much extra work this would be.  Neither
program implements conditionals.
 
On the whole, Roff looks more general and easier to port and extend than
Nroff.  Is it worth trying to set up a standard set of escapes (fonts,
super/subscript, continuous underline, etc. to make porting easier?  Has
anyone added some of the missing bits?
 
The following shell script is a roff post-processor for the Epson RX-80.
 
================================ cut here ==============================
echo x - termeprx.c
sed '/^X/s///' > termeprx.c << '/'
X/* roff post-processor for Epson RX-80.  Version 0.2 of 10 Feb 90 */
X
X#include "stdio.h"
X#include "term.h"
X
Xchar progname[] = "termeprx";
Xint Offset ;  /* super/subscript commands are absolute not relative */
X
Xmain()
X{
X  register int c;
X
X  Offset = 0 ;
X  while (!feof(stdin)) {
X       c = getchar();
X       switch (c) {
X       case ESCAPE:    getpc();        break;
X       case EOF:       break;
X       default:        putchar(c);     break;
X       }
X  }
X}
X
Xgetpc()
X{
X  register int c;
X
X  c = getchar();
X  switch (c) {
X      case ROMAN:      roman();        break;
X      case ITALIC:     italic();       break;
X      case BOLD:       bold();         break;
X      case HALFUP:     if (Offset < 0)
X                               middle() ;
X                       else if (Offset == 0)
X                               halfup() ;
X                       break;
X      case HALFDOWN:   if (Offset > 0)
X                               middle() ;
X                       else if (Offset == 0)
X                               halfdown() ;
X                       break;
X      default:
X       fprintf(stderr, "%s:  unrecognized output escape sequence ESC-0x%x
\n", progname, c);
X       break;
X  }
X}
X
Xroman()
X{
X  printf("\0335\033H"); /* cancel italic and bold */
X}
X
Xitalic()
X{
X  printf("\0334");
X}
X
Xbold()
X{
X  printf("\033G");
X}
X
Xhalfup()
X{
X  printf("\033S\060");
X  Offset = 1 ;
X}
X
Xhalfdown()
X{
X  printf("\033S\061");
X  Offset = -1 ;
X}
X
Xmiddle() /* reset halfup or halfdown */
X{
X  printf("\033T");
X  Offset = 0 ;
X}
/
-----------------------------------------------------------------------
"If heaven too had passions  | Will Rose
     even heaven would       | UUCP: {nosc ucsd hplabs!hp-sdd}!crash!pnet01!cw
     grow old."  -  Li Ho.   | ARPA: crash!pnet01!cwr@nosc.mil
                             | INET: cwr@pnet01.cts.com


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