#ifndef lint
static char rcsid[] = "$Header: text.c,v 0.0 88/06/22 05:22:51 on Rel $";
#endif
#include <stdio.h>
#include <ctype.h>
#include "pps.h"
/*
 * "Lexical analizer" for plain text (e.g. the output of nroff(1)):
 * Prints _\b. and .\b_ in italics; c\bc in bold.
 */
FILE *yyin = stdin;
FILE *yyout = stdout;
char *keywords[1];

static
struct ca {
	char c;		/* character to print */
	char a;		/* font to use */
} ca[BUFSIZ];

#define ITALIC	'S'
#define NORM	'I'
#define BOLD	'K'

/*
 * Add character c at position cap.
 */
static
caput(c, cap)
register c;
register struct ca *cap;
{
	switch (cap->c) {
		case '_':
			cap->a = ITALIC;
			break;
		case '\0':
		case ' ':
			cap->a = NORM;
			break;
		default:
			switch (c) {
				case '_':
					cap->a = ITALIC;
					return;
				default:
					if (cap->c == c)
						cap->a = BOLD;
				case ' ':
					break;
			}
	}
	cap->c = c;
}

/*
 * Print text collected so far.
 */
static
caflush(caend)
struct ca *caend;
{
	char buf[BUFSIZ];
	register struct ca *cap;
	static struct ca zeroca;

	for (cap = ca; cap < caend;) {
		register char *cp = buf;

		while (cap < caend && cap->a == *font) {
			*cp++ = cap->c;
			*cap++ = zeroca;
		}
		*cp = '\0';
		echo(buf);
		sput();
		if (cap->a)
			*font = cap->a;
	}
}

/*
 * Process input text:
 *	Call space() for [\t\n\f],
 *	Save others in ca.
 */
yylex()
{
	register struct ca *cap = ca;
	static char sp[2];

	for (;;) {
		register c;

		while (isprint(c = getc(yyin)) || c == ' ')
			caput(c, cap++);
		
		switch (c) {
			default:
				continue;
			case '\b':
				if (cap > ca)
					cap--;
				continue;
			case '\r':	/* BUG -- won't work after \t */
				cap = ca;
				continue;
			case '\t':
			case '\n':
			case '\f':
			case EOF:
				break;
		}
		caflush(cap);
		cap = ca;
		if (c == EOF)
			return;
		*sp = c;
		space(sp);
	}
}