Roff in C (blank lines & leading spaces)

[Tim Maroney]

The posting of the C version of roff created the following comment:

> The posted version of this program does not work and was apparently
> never tested.  As posted, any request at the beginning of a text file
> causes the whole file to be skipped because of a logic error in the
> basic input routine, called "suck()."  It is well named.  Leading
> spaces do not cause a line break since the logic to do this is missing.
> Blank lines disappear.  Doubtless there are other bugs as well.
> 
> Pity.  Would have been useful.

The statement about an initial request gobbling the whole file is just plain
false.  I have tested it with a few different requests as the first line of
the text file, without any problems.  It would have been nice if the person
had told us what request caused this error.

However, he was right that blank lines and lines with leading spaces do not
create the desired effect.  Fortunately, this is easy to fix.  Here is the
new version of the function readline() which provides the desired
functionality.  Just replace the old version of the function with this.

readline()
{
	int startline, doingword;
	isrequest = 0;
	startline = 1;
	doingword = 0;
	c=suck();
	if (c == '\n') {
		o_sp = 1;
		writebreak();
		goto out;
	}
	else if (isspace(c))
		writebreak();
	for (;;) {
		if (c==EOF) {
			if (doingword) bumpword();
			break;
		}
		if (c!=o_cc && o_ig) {
			while (c!='\n' && c!=EOF) c=suck();
			break;
		}
		if (isspace(c) && !doingword) {
			startline=0;
			switch (c) {
			case ' ':
				assyline[assylen++]=' ';
				break;
			case '\t':
				tabulate();
				break;
			case '\n':
				goto out;
			}
			c = suck();
			continue;
		}
		if (isspace(c) && doingword) {
			bumpword();
			if (c=='\t') tabulate();
			else if (assylen) assyline[assylen++]=' ';
			doingword=0;
			if (c=='\n') break;
		}
		if (!isspace(c)) {
			if (doingword) *holdp++ = o_ul? c|UNDERL: c;
			else if (startline && c==o_cc && !o_li) {
				isrequest=1;
				return readreq();
			}
			else {
				doingword=1;
				holdp=holdword;
				*holdp++ = o_ul? c|UNDERL: c;
			}
		}
		startline=0;
		c = suck();
	}
out:
	if (o_ul) o_ul--;
	center=o_ce;
	if (o_ce) o_ce--;
	if (o_li) o_li--;
	return c!=EOF;
}

Now what roff really needs is to separate the UNIX dependencies from the
rest of the code, and to add font support.  I intend to use it with the
smallc compiler on CP/M.  When I finish converting it, I will post the
smallc version here.
-=-
Tim Maroney, Carnegie-Mellon University Computation Center
ARPA:	Tim.Maroney at CMU-CS-K	uucp:	seismo!cmu-cs-k!tim
CompuServe:	74176,1360	audio:	shout "Hey, Tim!"

"Remember all ye that existence is pure joy; that all the sorrows are
but as shadows; they pass & are done; but there is that which remains."
Liber AL, II:9.