Issue a STYLE message when normalizing the date format in .Dd/.TH.

Leah Neukirchen pointed out that mdoclint(1) used to warn about a
leading zero before the day number, so we know that both NetBSD and
Void Linux want the message.  It does no harm on OpenBSD because
Mdocdate always does the right thing anyway.
jmc@ agrees that it makes sense in contexts not using Mdocdate.

5 files changed, 29 insertions, 14 deletions

diff --git a/mandoc.1 b/mandoc.1
index 482af608..76b3cda5 100644
--- a/mandoc.1
+++ b/mandoc.1
@@ -1,4 +1,4 @@
-.\"	$Id: mandoc.1,v 1.225 2018/05/03 14:21:46 schwarze Exp $
+.\"	$Id: mandoc.1,v 1.226 2018/07/28 18:34:15 schwarze Exp $
 .\"
 .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 .\" Copyright (c) 2012, 2014-2018 Ingo Schwarze <schwarze@openbsd.org>
@@ -15,7 +15,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: May 3 2018 $
+.Dd $Mdocdate: July 28 2018 $
 .Dt MANDOC 1
 .Os
 .Sh NAME
@@ -853,6 +853,16 @@ Consider using the conventional
 date format
 .Dq "Month dd, yyyy"
 instead.
+.It Sy "normalizing date format to" : No ...
+.Pq mdoc , man
+The
+.Ic \&Dd
+or
+.Ic \&TH
+macro provides an abbreviated month name or a day number with a
+leading zero.
+In the formatted output, the month name is written out in full
+and the leading zero is omitted.
 .It Sy "lower case character in document title"
 .Pq mdoc , man
 The title is still used as given in the
diff --git a/mandoc.c b/mandoc.c
index 3e16d2c6..1279b52e 100644
--- a/mandoc.c
+++ b/mandoc.c
@@ -1,7 +1,7 @@
-/*	$Id: mandoc.c,v 1.103 2017/07/03 13:40:19 schwarze Exp $ */
+/*	$Id: mandoc.c,v 1.104 2018/07/28 18:34:15 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2011-2015, 2017 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2011-2015, 2017, 2018 Ingo Schwarze <schwarze@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -541,6 +541,9 @@ mandoc_normdate(struct roff_man *man, char *in, int ln, int pos)
 		if (t > time(NULL) + 86400)
 			mandoc_msg(MANDOCERR_DATE_FUTURE, man->parse,
 			    ln, pos, cp);
+		else if (*in != '$' && strcmp(in, cp) != 0)
+			mandoc_msg(MANDOCERR_DATE_NORM, man->parse,
+			    ln, pos, cp);
 		return cp;
 	}
 
diff --git a/mandoc.h b/mandoc.h
index fef9be8f..dbc266cc 100644
--- a/mandoc.h
+++ b/mandoc.h
@@ -1,7 +1,7 @@
-/*	$Id: mandoc.h,v 1.247 2018/03/16 15:05:44 schwarze Exp $ */
+/*	$Id: mandoc.h,v 1.248 2018/07/28 18:34:15 schwarze Exp $ */
 /*
  * Copyright (c) 2010, 2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2010-2017 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2010-2018 Ingo Schwarze <schwarze@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -56,6 +56,7 @@ enum	mandocerr {
 	MANDOCERR_STYLE, /* ===== start of style suggestions ===== */
 
 	MANDOCERR_DATE_LEGACY, /* legacy man(7) date format: Dd ... */
+	MANDOCERR_DATE_NORM, /* normalizing date format to: ... */
 	MANDOCERR_TITLE_CASE, /* lower case character in document title */
 	MANDOCERR_RCS_REP, /* duplicate RCS id: ... */
 	MANDOCERR_SEC_TYPO,  /* possible typo in section name: Sh ... */
diff --git a/mdoc.7 b/mdoc.7
index 1efd8cf0..5c07434c 100644
--- a/mdoc.7
+++ b/mdoc.7
@@ -1,7 +1,7 @@
-.\"	$Id: mdoc.7,v 1.270 2017/10/23 13:54:41 schwarze Exp $
+.\"	$Id: mdoc.7,v 1.271 2018/07/28 18:34:15 schwarze Exp $
 .\"
 .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
-.\" Copyright (c) 2010, 2011, 2013-2017 Ingo Schwarze <schwarze@openbsd.org>
+.\" Copyright (c) 2010, 2011, 2013-2018 Ingo Schwarze <schwarze@openbsd.org>
 .\"
 .\" Permission to use, copy, modify, and distribute this software for any
 .\" purpose with or without fee is hereby granted, provided that the above
@@ -15,7 +15,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: October 23 2017 $
+.Dd $Mdocdate: July 28 2018 $
 .Dt MDOC 7
 .Os
 .Sh NAME
@@ -1234,7 +1234,7 @@ The
 .Ar month
 is the full English month name, the
 .Ar day
-is an optionally zero-padded numeral, and the
+is an integer number, and the
 .Ar year
 is the full four-digit year.
 .Pp
@@ -1264,8 +1264,8 @@ If no date string is given, the current date is used.
 .Pp
 Examples:
 .Dl \&.Dd $\&Mdocdate$
-.Dl \&.Dd $\&Mdocdate: July 21 2007$
-.Dl \&.Dd July 21, 2007
+.Dl \&.Dd $\&Mdocdate: July 2 2018$
+.Dl \&.Dd July 2, 2018
 .Pp
 See also
 .Sx \&Dt
diff --git a/read.c b/read.c
index 0fc4f6e3..0a583445 100644
--- a/read.c
+++ b/read.c
@@ -1,7 +1,7 @@
-/*	$Id: read.c,v 1.195 2018/03/16 15:05:44 schwarze Exp $ */
+/*	$Id: read.c,v 1.196 2018/07/28 18:34:15 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2010-2017 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2010-2018 Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2010, 2012 Joerg Sonnenberger <joerg@netbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
@@ -94,6 +94,7 @@ static	const char * const	mandocerrs[MANDOCERR_MAX] = {
 	"generic style suggestion",
 
 	"legacy man(7) date format",
+	"normalizing date format to",
 	"lower case character in document title",
 	"duplicate RCS id",
 	"possible typo in section name",