Add compatibility with POSIX more.

NEWS.VER

@@ -15,6 +15,8 @@
 
 	Major changes between "less" versions 394 and @@VERSION@@
 
+* Add compatibility with POSIX more.
+
 * Allow "/dev/null" as synomym for "-" in LESSHISTFILE.
 
 * Make -f work for directories.

command.c

@@ -23,7 +23,6 @@
 
 extern int erase_char, erase2_char, kill_char;
 extern int sigs;
-extern int quit_at_eof;
 extern int quit_if_one_screen;
 extern int squished;
 extern int hit_eof;
@@ -606,7 +605,7 @@ prompt()
 	 * {{ Relying on "first prompt" to detect a single-screen file
 	 * fails if +G is used, for example. }}
 	 */
-	if ((quit_at_eof == OPT_ONPLUS || quit_if_one_screen) &&
+	if ((get_quit_at_eof() == OPT_ONPLUS || quit_if_one_screen) &&
 	    hit_eof && !(ch_getflags() & CH_HELPFILE) && 
 	    next_ifile(curr_ifile) == NULL_IFILE)
 		quit(QUIT_OK);
@@ -616,7 +615,7 @@ prompt()
 	 * If the -e flag is set and we've hit EOF on the last file,
 	 * and the file is squished (shorter than the screen), quit.
 	 */
-	if (quit_at_eof && squished &&
+	if (get_quit_at_eof() && squished &&
 	    next_ifile(curr_ifile) == NULL_IFILE)
 		quit(QUIT_OK);
 #endif
@@ -1386,7 +1385,7 @@ commands()
 				number = 1;
 			if (edit_next((int) number))
 			{
-				if (quit_at_eof && hit_eof && 
+				if (get_quit_at_eof() && hit_eof && 
 				    !(ch_getflags() & CH_HELPFILE))
 					quit(QUIT_OK);
 				parg.p_string = (number > 1) ? "(N-th) " : "";

forwback.c

@@ -26,7 +26,6 @@ extern int sigs;
 extern int top_scroll;
 extern int quiet;
 extern int sc_width, sc_height;
-extern int quit_at_eof;
 extern int plusoption;
 extern int forw_scroll;
 extern int back_scroll;
@@ -324,7 +323,7 @@ forward(n, force, only_last)
 {
 	POSITION pos;
 
-	if (quit_at_eof && hit_eof && !(ch_getflags() & CH_HELPFILE))
+	if (get_quit_at_eof() && hit_eof && !(ch_getflags() & CH_HELPFILE))
 	{
 		/*
 		 * If the -e flag is set and we're trying to go

less.nro.VER

@@ -806,7 +806,7 @@ By default, any forward movement causes scrolling.
 Changes the default scrolling window size to \fIn\fP lines.
 The default is one screenful.
 The z and w commands can also be used to change the window size.
-The "z" may be omitted for compatibility with
+The "z" may be omitted for compatibility with some versions of 
 .I more.
 If the number
 .I n
@@ -1446,6 +1446,36 @@ filename completion (TAB, ^L)
 .PP
 Less can also be compiled to be permanently in "secure" mode.
 
+.SH "COMPATIBILITY WITH MORE"
+If the environment variable LESS_IS_MORE is set to 1,
+or if the program is invoked via a file link named "more",
+.I less
+behaves (mostly) in conformance with the POSIX "more" command specification.
+In this mode, less behaves differently in these ways:
+.PP
+The \-e option works differently.
+If the \-e option is not set, 
+.I less
+behaves as if the \-E option were set.
+If the \-e option is set, 
+.I less
+behaves as if the \-e and \-F options were set.
+.PP
+The \-m option works differently.
+If the \-m option is not set, the medium prompt is used,
+and it is prefixed with the string "--More--".
+If the \-m option is set, the short prompt is used.
+.PP
+The \-n option acts like the \-z option.
+The normal behavior of the \-n option is unavailable in this mode.
+.PP
+The parameter to the \-p option is taken to be a 
+.I less
+command rather than a search pattern.
+.PP
+The LESS environment variable is ignored,
+and the MORE environment variable is used in its place.
+
 .SH "ENVIRONMENT VARIABLES"
 Environment variables may be specified either in the system environment
 as usual, or in a 
@@ -1538,6 +1568,10 @@ See discussion under SECURITY.
 String to be appended to a directory name in filename completion.
 .IP LESSUTFBINFMT
 Format for displaying non-printable Unicode code points.
+.IP LESS_IS_MORE
+Emulate the 
+.I more
+(1) command.
 .IP LINES
 Sets the number of lines on the screen.
 Takes precedence over the number of lines specified by the TERM variable.

main.c

@@ -32,6 +32,7 @@ public char *	progname;
 public int	quitting;
 public int	secure;
 public int	dohelp;
+public int	less_is_more;
 
 #if LOGFILE
 public int	logfile = -1;
@@ -56,6 +57,8 @@ static char consoleTitle[256];
 
 extern int	missing_cap;
 extern int	know_dumb;
+extern int	quit_if_one_screen;
+extern int	pr_type;
 
 
 /*
@@ -111,12 +114,28 @@ main(argc, argv)
 	is_tty = isatty(1);
 	get_term();
 	init_cmds();
-	init_prompt();
 	init_charset();
 	init_line();
 	init_cmdhist();
 	init_option();
-	s = lgetenv("LESS");
+
+	/*
+	 * If the name of the executable program is "more",
+	 * act like LESS_IS_MORE is set.
+	 */
+	for (s = argv[0] + strlen(argv[0]);  s > argv[0];  s--)
+	{
+		if (s[-1] == '/')
+			break;
+		if (s[-1] == '\\')
+			break;
+	}
+	if (strcmp(s, "more") == 0)
+		less_is_more = 1;
+
+	init_prompt();
+
+	s = lgetenv(less_is_more ? "MORE" : "LESS");
 	if (s != NULL)
 		scan_option(save(s));
 
@@ -141,6 +160,9 @@ main(argc, argv)
 		quit(QUIT_OK);
 	}
 
+	if (less_is_more && get_quit_at_eof())
+		quit_if_one_screen = TRUE;
+
 #if EDITOR
 	editor = lgetenv("VISUAL");
 	if (editor == NULL || *editor == '\0')

optfunc.c

@@ -37,7 +37,6 @@ extern int sc_height;
 extern int secure;
 extern int dohelp;
 extern int any_display;
-extern int less_is_more;
 extern char openquote;
 extern char closequote;
 extern char *prproto[];
@@ -55,6 +54,7 @@ extern int logfile;
 public char *tagoption = NULL;
 extern char *tags;
 extern int jump_sline;
+extern int less_is_more;
 #endif
 #if MSDOS_COMPILER
 extern int nm_fg_color, nm_bg_color;
@@ -267,7 +267,7 @@ opt_p(type, s)
 		 * In "more" mode, the -p argument is a command,
 		 * not a search string, so we don't need a slash.
 		 */
-		if (!less_is_more);
+		if (!less_is_more)
 			ungetsc("/");
 		break;
 	}

option.c

@@ -29,6 +29,8 @@ static char *optstring();
 static int flip_triple();
 
 extern int screen_trashed;
+extern int less_is_more;
+extern int quit_at_eof;
 extern char *every_first_cmd;
 
 /* 
@@ -132,6 +134,10 @@ scan_option(s)
 			s--;
 			optc = 'z';
 			break;
+		case 'n':
+			if (less_is_more)
+				optc = 'z';
+			break;
 		}
 
 		/*
@@ -631,3 +637,15 @@ getnum(sp, printopt, errp)
 		n = -n;
 	return (n);
 }
+
+/*
+ * Get the value of the -e flag.
+ */
+	public int
+get_quit_at_eof()
+{
+	if (!less_is_more)
+		return quit_at_eof;
+	/* When less_is_more is set, the -e flag semantics are different. */
+	return quit_at_eof ? OPT_ON : OPT_ONPLUS;
+}

prompt.c

@@ -30,6 +30,7 @@ extern int linenums;
 extern int hshift;
 extern int sc_height;
 extern int jump_sline;
+extern int less_is_more;
 extern IFILE curr_ifile;
 #if EDITOR
 extern char *editor;
@@ -52,6 +53,8 @@ static constant char h_proto[] =
   "HELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done";
 static constant char w_proto[] =
   "Waiting for data";
+static constant char more_proto[] =
+  "--More--(?eEND ?x- Next\\: %x.:?pB%pB\\%:byte %bB?s/%s...%t)";
 
 public char *prproto[3];
 public char constant *eqproto = e_proto;
@@ -68,7 +71,7 @@ static char *mp;
 init_prompt()
 {
 	prproto[0] = save(s_proto);
-	prproto[1] = save(m_proto);
+	prproto[1] = save(less_is_more ? more_proto : m_proto);
 	prproto[2] = save(M_proto);
 	eqproto = save(e_proto);
 	hproto = save(h_proto);
@@ -561,9 +564,11 @@ eq_message()
 pr_string()
 {
 	char *prompt;
+	int type;
 
+	type = (!less_is_more) ? pr_type : pr_type ? 0 : 1;
 	prompt = pr_expand((ch_getflags() & CH_HELPFILE) ?
-				hproto : prproto[pr_type],
+				hproto : prproto[type],
 			sc_width-so_s_width-so_e_width-2);
 	new_file = 0;
 	return (prompt);

version.c

@@ -674,6 +674,7 @@ v395  1/12/07	Update Unicode tables (thanks to Charles Levert);
 		make -f work for directories; support DESTDIR in Makefile;
 		fix setset_t detection in configure; 
 		make "t" cmd traverse tags in correct order
+v396  1/13/07	Add compatibility with POSIX more.
 */
 
-char version[] = "395";
+char version[] = "396";