[v2 PATCH 0/2] Pull Request

[v2 PATCH 0/2] Pull Request

[J William Piggott]

 v2 changelog
 * fix typo in v1
 * move REFORMATION_YEAR to the control struct
 * add more about the --1752-reform option to man page
 * add a second patch with minor style and wording changes

The following changes since commit 43afa84581de8984aa00ef2e9208198929f72ddf:

  lib/mbsalign: encode \x to \xecx (2017-12-20 13:01:43 +0100)

are available in the git repository at:

  git@github.com:jwpi/util-linux.git 171219

for you to fetch changes up to 5be40a1748e3f39ed976edfca3d45240e350cb8b:

  cal: change reformation to reform (2017-12-22 20:22:03 -0500)

----------------------------------------------------------------
J William Piggott (2):
      cal: add --iso and --1752-reform format options
      cal: change reformation to reform

 misc-utils/cal.1 |  25 ++++++++---
 misc-utils/cal.c | 134 ++++++++++++++++++++++++++++++++++---------------------
 2 files changed, 100 insertions(+), 59 deletions(-)

[v2 PATCH 1/2] cal: add --iso and --1752-reform format options

[J William Piggott]

Signed-off-by: J William Piggott <elseifthen@gmx.com>
---
 misc-utils/cal.1 |  21 ++++++++---
 misc-utils/cal.c | 104 +++++++++++++++++++++++++++++++++++--------------------
 2 files changed, 82 insertions(+), 43 deletions(-)

diff --git a/misc-utils/cal.1 b/misc-utils/cal.1
index f1084edba..6706d9df2 100644
--- a/misc-utils/cal.1
+++ b/misc-utils/cal.1
@@ -55,12 +55,21 @@ abbreviated month name according to the current locales.
 .SH OPTIONS
 .TP
 \fB\-1\fR, \fB\-\-one\fR
-Display single month output.
-(This is the default.)
+Display single month output (default).
 .TP
 \fB\-3\fR, \fB\-\-three\fR
 Display three months spanning the date.
 .TP
+.B \-\-1752-reform
+Display calendars based upon the Chesterfield's Act (default).
+This means that dates previous to Sept 14, 1752 will be Julian calendar dates.
+.RB See \ BUGS \ below.
+.TP
+.B \-\-iso
+Display calendars based upon the ISO 8601 proleptic Gregorian format.
+This means that dates previous to calendar reform use extrapolated Gregorian
+dates instead of Julian calendar dates.
+.TP
 \fB\-n , \-\-months\fR \fInumber\fR
 Display \fInumber\fR of months, starting from the month containing the date.
 .TP
@@ -148,14 +157,16 @@ See
 for more details about colorization configuration.
 .SH BUGS
 .PP
-The
+The default
 .B cal
-program uses the 3rd of September 1752 as the date of the Gregorian calendar
+format uses the 3rd of September 1752 as the date of the Gregorian calendar
 reformation -- that is when it happened in Great Britain and its colonies
 (including what is now the USA).  Starting at that date, eleven days were eliminated
 by this reformation, so the calendar for that month is rather unusual.
 The actual historical dates at which the calendar reform happened in all the
-different countries (locales) are ignored.
+different countries (locales), including its introduction by Pope Gregory XIII
+in October 1582, are ignored. The Gregorian calendar is a refinement to the
+Julian calendar improving its synchronization with solar cycles.
 .PP
 Alternative calendars, such as the Umm al-Qura, the Solar Hijri, the Ge'ez,
 or the lunisolar Hindu, are not supported.
diff --git a/misc-utils/cal.c b/misc-utils/cal.c
index 39f2bdcba..140c89840 100644
--- a/misc-utils/cal.c
+++ b/misc-utils/cal.c
@@ -160,7 +160,6 @@ enum {
 	DECEMBER
 };
 
-#define REFORMATION_YEAR	1752		/* Signed-off-by: Lord Chesterfield */
 #define REFORMATION_MONTH	SEPTEMBER
 #define	NUMBER_MISSING_DAYS	11		/* 11 day correction */
 #define YDAY_AFTER_MISSING	258             /* 14th in Sep 1752 */
@@ -206,6 +205,7 @@ struct cal_control {
 	const char *full_month[MONTHS_IN_YEAR];	/* month names */
 	const char *abbr_month[MONTHS_IN_YEAR];	/* abbreviated month names */
 
+	int reform_year;		/* Gregorian reform year */
 	int colormode;			/* day and week number highlight */
 	int num_months;			/* number of requested months */
 	int span_months;		/* span the date */
@@ -230,7 +230,7 @@ struct cal_month {
 };
 
 /* function prototypes */
-static int leap_year(int32_t year);
+static int leap_year(const struct cal_control *ctl, int32_t year);
 static int monthname_to_number(struct cal_control *ctl, const char *name);
 static void headers_init(struct cal_control *ctl);
 static void cal_fill_month(struct cal_month *month, const struct cal_control *ctl);
@@ -238,8 +238,10 @@ static void cal_output_header(struct cal_month *month, const struct cal_control
 static void cal_output_months(struct cal_month *month, const struct cal_control *ctl);
 static void monthly(const struct cal_control *ctl);
 static void yearly(const struct cal_control *ctl);
-static int day_in_year(int day, int month, int32_t year);
-static int day_in_week(int day, int month, int32_t year);
+static int day_in_year(const struct cal_control *ctl, int day,
+		       int month, int32_t year);
+static int day_in_week(const struct cal_control *ctl, int day,
+		       int month, int32_t year);
 static int week_number(int day, int month, int32_t year, const struct cal_control *ctl);
 static int week_to_day(const struct cal_control *ctl);
 static int center_str(const char *src, char *dest, size_t dest_size, size_t width);
@@ -252,7 +254,13 @@ int main(int argc, char **argv)
 	char *term;
 	time_t now;
 	int ch = 0, yflag = 0, Yflag = 0;
+
+/*
+ * FIXME Dec 19 2017 - After an appropriate mourning period change reform_year
+ * to -1 making the default output format the proleptic Gregorian calendar.
+ */
 	static struct cal_control ctl = {
+		.reform_year = 1752,
 		.weekstart = SUNDAY,
 		.num_months = 1,		/* default is "cal -1" */
 		.span_months = 0,
@@ -265,7 +273,9 @@ int main(int argc, char **argv)
 	};
 
 	enum {
-		OPT_COLOR = CHAR_MAX + 1
+		OPT_COLOR = CHAR_MAX + 1,
+		OPT_ISO,
+		OPT_1752_REFORM
 	};
 
 	static const struct option longopts[] = {
@@ -279,6 +289,8 @@ int main(int argc, char **argv)
 		{"year", no_argument, NULL, 'y'},
 		{"week", optional_argument, NULL, 'w'},
 		{"color", optional_argument, NULL, OPT_COLOR},
+		{"iso", no_argument, NULL, OPT_ISO},
+		{"1752-reform", no_argument, NULL, OPT_1752_REFORM},
 		{"version", no_argument, NULL, 'V'},
 		{"twelve", no_argument, NULL, 'Y'},
 		{"help", no_argument, NULL, 'h'},
@@ -335,7 +347,8 @@ int main(int argc, char **argv)
 		val.string = nl_langinfo(_NL_TIME_WEEK_1STDAY);
 
 		wfd = val.word;
-		wfd = day_in_week(wfd % 100, (wfd / 100) % 100, wfd / (100 * 100));
+		wfd = day_in_week(&ctl, wfd % 100, (wfd / 100) % 100,
+				  wfd / (100 * 100));
 		ctl.weekstart = (wfd + *nl_langinfo(_NL_TIME_FIRST_WEEKDAY) - 1) % DAYS_IN_WEEK;
 	}
 #endif
@@ -390,6 +403,12 @@ int main(int argc, char **argv)
 				ctl.colormode = colormode_or_err(optarg,
 						_("unsupported color mode"));
 			break;
+		case OPT_1752_REFORM:
+			ctl.reform_year = 1752;
+			break;
+		case OPT_ISO:
+			ctl.reform_year = -1;
+			break;
 		case 'V':
 			printf(UTIL_LINUX_VERSION);
 			return EXIT_SUCCESS;
@@ -451,10 +470,12 @@ int main(int argc, char **argv)
 		if (ctl.req.year == INT32_MAX)
 			errx(EXIT_FAILURE, _("illegal year value"));
 		if (ctl.req.day) {
-			int dm = days_in_month[leap_year(ctl.req.year)][ctl.req.month];
+			int dm = days_in_month[leap_year(&ctl, ctl.req.year)]
+					      [ctl.req.month];
 			if (ctl.req.day > dm)
 				errx(EXIT_FAILURE, _("illegal day value: use 1-%d"), dm);
-			ctl.req.day = day_in_year(ctl.req.day, ctl.req.month, ctl.req.year);
+			ctl.req.day = day_in_year(&ctl, ctl.req.day,
+						  ctl.req.month, ctl.req.year);
 		} else if ((int32_t) (local_time->tm_year + 1900) == ctl.req.year) {
 			ctl.req.day = local_time->tm_yday + 1;
 		}
@@ -476,7 +497,7 @@ int main(int argc, char **argv)
 
 	if (0 < ctl.req.week) {
 		int yday = week_to_day(&ctl);
-		int leap = leap_year(ctl.req.year);
+		int leap = leap_year(&ctl, ctl.req.year);
 		int m = 1;
 
 		if (yday < 1)
@@ -532,9 +553,9 @@ int main(int argc, char **argv)
 }
 
 /* leap year -- account for gregorian reformation in 1752 */
-static int leap_year(int32_t year)
+static int leap_year(const struct cal_control *ctl, int32_t year)
 {
-	if (year <= REFORMATION_YEAR)
+	if (year <= ctl->reform_year)
 		return !(year % 4);
 	else
 		return ( !(year % 4) && (year % 100) ) || !(year % 400);
@@ -618,15 +639,15 @@ static void headers_init(struct cal_control *ctl)
 
 static void cal_fill_month(struct cal_month *month, const struct cal_control *ctl)
 {
-	int first_week_day = day_in_week(1, month->month, month->year);
+	int first_week_day = day_in_week(ctl, 1, month->month, month->year);
 	int month_days;
 	int i, j, weeklines = 0;
 
 	if (ctl->julian)
-		j = day_in_year(1, month->month, month->year);
+		j = day_in_year(ctl, 1, month->month, month->year);
 	else
 		j = 1;
-	month_days = j + days_in_month[leap_year(month->year)][month->month];
+	month_days = j + days_in_month[leap_year(ctl, month->year)][month->month];
 
 	/* True when Sunday is not first day in the output week. */
 	if (ctl->weekstart) {
@@ -644,7 +665,9 @@ static void cal_fill_month(struct cal_month *month, const struct cal_control *ct
 			continue;
 		}
 		if (j < month_days) {
-			if (month->year == REFORMATION_YEAR && month->month == REFORMATION_MONTH && (j == 3 || j == 247))
+			if (month->year == ctl->reform_year &&
+			    month->month == REFORMATION_MONTH &&
+			    (j == 3 || j == 247))
 				j += NUMBER_MISSING_DAYS;
 			month->days[i] = j;
 			j++;
@@ -726,9 +749,9 @@ static void cal_output_months(struct cal_month *month, const struct cal_control
 				if (ctl->julian)
 					reqday = ctl->req.day;
 				else
-					reqday =
-					    ctl->req.day + 1 - day_in_year(1, i->month,
-									   i->year);
+					reqday = ctl->req.day + 1 -
+						 day_in_year(ctl, 1, i->month,
+							     i->year);
 			}
 
 			if (ctl->weektype) {
@@ -847,11 +870,12 @@ static void yearly(const struct cal_control *ctl)
  * day_in_year --
  *	return the 1 based day number within the year
  */
-static int day_in_year(int day, int month, int32_t year)
+static int day_in_year(const struct cal_control *ctl,
+		       int day, int month, int32_t year)
 {
 	int i, leap;
 
-	leap = leap_year(year);
+	leap = leap_year(ctl, year);
 	for (i = 1; i < month; i++)
 		day += days_in_month[leap][i];
 	return day;
@@ -864,7 +888,8 @@ static int day_in_year(int day, int month, int32_t year)
  *	3 Sep. 1752 through 13 Sep. 1752, and returns invalid weekday
  *	during the period of 11 days.
  */
-static int day_in_week(int day, int month, int32_t year)
+static int day_in_week(const struct cal_control *ctl, int day,
+		       int month, int32_t year)
 {
 	/*
 	* The magic constants in the reform[] array are, in a simplified
@@ -886,20 +911,21 @@ static int day_in_week(int day, int month, int32_t year)
 	static const int reform[] = { 0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4 };
 	static const int old[]    = { 5, 1, 0, 3, 5, 1, 3, 6, 2, 4, 0, 2 };
 
-	if (year != REFORMATION_YEAR + 1)
+	if (year != ctl->reform_year + 1)
 		year -= month < MARCH;
 	else
 		year -= (month < MARCH) + 14;
-	if (REFORMATION_YEAR < year
-	    || (year == REFORMATION_YEAR && REFORMATION_MONTH < month)
-	    || (year == REFORMATION_YEAR && month == REFORMATION_MONTH && 13 < day)) {
+	if (ctl->reform_year < year
+	    || (year == ctl->reform_year && REFORMATION_MONTH < month)
+	    || (year == ctl->reform_year
+	    && month == REFORMATION_MONTH && 13 < day)) {
 		int64_t long_year = year;
-		return (long_year + (year / 4) - (year / 100) + (year / 400) + reform[month - 1] +
-			day) % DAYS_IN_WEEK;
+		return (long_year + (year / 4) - (year / 100) + (year / 400) +
+			reform[month - 1] + day) % DAYS_IN_WEEK;
 	}
-	if (year < REFORMATION_YEAR
-	    || (year == REFORMATION_YEAR && month < REFORMATION_MONTH)
-	    || (year == REFORMATION_YEAR && month == REFORMATION_MONTH && day < 3))
+	if (year < ctl->reform_year
+	    || (year == ctl->reform_year && month < REFORMATION_MONTH)
+	    || (year == ctl->reform_year && month == REFORMATION_MONTH && day < 3))
 		return (year + year / 4 + old[month - 1] + day) % DAYS_IN_WEEK;
 	return NONEDAY;
 }
@@ -914,7 +940,7 @@ static int day_in_week(int day, int month, int32_t year)
 static int week_number(int day, int month, int32_t year, const struct cal_control *ctl)
 {
 	int fday = 0, yday;
-	const int wday = day_in_week(1, JANUARY, year);
+	const int wday = day_in_week(ctl, 1, JANUARY, year);
 
 	if (ctl->weektype & WEEK_NUM_ISO)
 		fday = wday + (wday >= FRIDAY ? -2 : 5);
@@ -930,8 +956,8 @@ static int week_number(int day, int month, int32_t year, const struct cal_contro
 	if (day > DAYS_IN_MONTH)
 		month = JANUARY;
 
-	yday = day_in_year(day,month,year);
-	if (year == REFORMATION_YEAR && yday >= YDAY_AFTER_MISSING)
+	yday = day_in_year(ctl, day, month, year);
+	if (year == ctl->reform_year && yday >= YDAY_AFTER_MISSING)
 		fday -= NUMBER_MISSING_DAYS;
 
 	/* Last year is last year */
@@ -942,10 +968,10 @@ static int week_number(int day, int month, int32_t year, const struct cal_contro
 	 * days than 365 making this check invalid, but reformation year ended
 	 * on Sunday and in week 51, so it's ok here. */
 	if (ctl->weektype == WEEK_NUM_ISO && yday >= 363
-	    && day_in_week(day, month, year) >= MONDAY
-	    && day_in_week(day, month, year) <= WEDNESDAY
-	    && day_in_week(31, DECEMBER, year) >= MONDAY
-	    && day_in_week(31, DECEMBER, year) <= WEDNESDAY)
+	    && day_in_week(ctl, day, month, year) >= MONDAY
+	    && day_in_week(ctl, day, month, year) <= WEDNESDAY
+	    && day_in_week(ctl, 31, DECEMBER, year) >= MONDAY
+	    && day_in_week(ctl, 31, DECEMBER, year) <= WEDNESDAY)
 		return week_number(1, JANUARY, year + 1, ctl);
 
 	return (yday + fday) / DAYS_IN_WEEK;
@@ -962,7 +988,7 @@ static int week_to_day(const struct cal_control *ctl)
 {
 	int yday, wday;
 
-	wday = day_in_week(1, JANUARY, ctl->req.year);
+	wday = day_in_week(ctl, 1, JANUARY, ctl->req.year);
 	yday = ctl->req.week * DAYS_IN_WEEK - wday;
 
 	if (ctl->weektype & WEEK_NUM_ISO)
@@ -1022,6 +1048,8 @@ static void __attribute__((__noreturn__)) usage(void)
 	fputs(_(" -y, --year            show the whole year\n"), out);
 	fputs(_(" -Y, --twelve          show the next twelve months\n"), out);
 	fputs(_(" -w, --week[=<num>]    show US or ISO-8601 week numbers\n"), out);
+	fputs(_("     --1752-reform     use Chesterfield's Act format\n"), out);
+	fputs(_("     --iso             use ISO 8601 proleptic Gregorian format\n"), out);
 	fputs(_("     --color[=<when>]  colorize messages (auto, always or never)\n"), out);
 	fprintf(out,
 	        "                         %s\n", USAGE_COLORS_DEFAULT);

[v2 PATCH 2/2] cal: change reformation to reform

[J William Piggott]

The proper term is calendar reform:
https://en.wikipedia.org/wiki/Calendar_reform

The term reformation is mostly associated with religion.

Also fix the reform[] array comment
and remove some extraneous tabs/spaces.

Signed-off-by: J William Piggott <elseifthen@gmx.com>
---
 misc-utils/cal.1 |  4 ++--
 misc-utils/cal.c | 42 ++++++++++++++++++++++--------------------
 2 files changed, 24 insertions(+), 22 deletions(-)

diff --git a/misc-utils/cal.1 b/misc-utils/cal.1
index 6706d9df2..a107f7b34 100644
--- a/misc-utils/cal.1
+++ b/misc-utils/cal.1
@@ -160,9 +160,9 @@ for more details about colorization configuration.
 The default
 .B cal
 format uses the 3rd of September 1752 as the date of the Gregorian calendar
-reformation -- that is when it happened in Great Britain and its colonies
+reform -- that is when it happened in Great Britain and its colonies
 (including what is now the USA).  Starting at that date, eleven days were eliminated
-by this reformation, so the calendar for that month is rather unusual.
+by this reform, so the calendar for that month is rather unusual.
 The actual historical dates at which the calendar reform happened in all the
 different countries (locales), including its introduction by Pope Gregory XIII
 in October 1582, are ignored. The Gregorian calendar is a refinement to the
diff --git a/misc-utils/cal.c b/misc-utils/cal.c
index 140c89840..aa05e3ac1 100644
--- a/misc-utils/cal.c
+++ b/misc-utils/cal.c
@@ -160,23 +160,23 @@ enum {
 	DECEMBER
 };
 
-#define REFORMATION_MONTH	SEPTEMBER
-#define	NUMBER_MISSING_DAYS	11		/* 11 day correction */
+#define REFORM_MONTH		SEPTEMBER
+#define NUMBER_MISSING_DAYS	11		/* 11 day correction */
 #define YDAY_AFTER_MISSING	258             /* 14th in Sep 1752 */
 
 #define MONTHS_IN_YEAR		DECEMBER
 #define DAYS_IN_MONTH		31
-#define	MAXDAYS			42		/* slots in a month array */
-#define	SPACE			-1		/* used in day array */
+#define MAXDAYS			42		/* slots in a month array */
+#define SPACE			-1		/* used in day array */
 
 #define SMALLEST_YEAR		1
 
-#define	DAY_LEN			3		/* 3 spaces per day */
-#define	WEEK_LEN		(DAYS_IN_WEEK * DAY_LEN)
+#define DAY_LEN			3		/* 3 spaces per day */
+#define WEEK_LEN		(DAYS_IN_WEEK * DAY_LEN)
 #define MONTHS_IN_YEAR_ROW	3		/* month columns in year view */
-#define WNUM_LEN                3
+#define WNUM_LEN		3
 
-#define FMT_ST_CHARS 300	/* 90 suffices in most locales */
+#define FMT_ST_CHARS		300	/* 90 suffices in most locales */
 
 static const int days_in_month[2][13] = {
 	{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
@@ -552,7 +552,7 @@ int main(int argc, char **argv)
 	return EXIT_SUCCESS;
 }
 
-/* leap year -- account for gregorian reformation in 1752 */
+/* leap year -- account for gregorian reform in 1752 */
 static int leap_year(const struct cal_control *ctl, int32_t year)
 {
 	if (year <= ctl->reform_year)
@@ -666,7 +666,7 @@ static void cal_fill_month(struct cal_month *month, const struct cal_control *ct
 		}
 		if (j < month_days) {
 			if (month->year == ctl->reform_year &&
-			    month->month == REFORMATION_MONTH &&
+			    month->month == REFORM_MONTH &&
 			    (j == 3 || j == 247))
 				j += NUMBER_MISSING_DAYS;
 			month->days[i] = j;
@@ -884,7 +884,7 @@ static int day_in_year(const struct cal_control *ctl,
 /*
  * day_in_week
  *	return the 0 based day number for any date from 1 Jan. 1 to
- *	31 Dec. 9999.  Assumes the Gregorian reformation eliminates
+ *	31 Dec. 9999.  Assumes the Gregorian reform eliminates
  *	3 Sep. 1752 through 13 Sep. 1752, and returns invalid weekday
  *	during the period of 11 days.
  */
@@ -895,8 +895,11 @@ static int day_in_week(const struct cal_control *ctl, int day,
 	* The magic constants in the reform[] array are, in a simplified
 	* sense, the remaining days after slicing into one week periods the total
 	* days from the beginning of the year to the target month. That is,
-	* weeks + reform[] days gets us to the target month. The exception is,
-	* that for the months past February 'DOY - 1' must be used.
+	* weeks + reform[] days gets us to the target month. Subtract one from
+	* the total days, before removing full weeks, to count the first day of
+	* the year. The exception is, the first two months need an extra day,
+	* because they are considered part of the previous year in the leap
+	* year handling scheme.
 	*
 	*   DoY (Day of Year): total days to the target month
 	*
@@ -916,16 +919,15 @@ static int day_in_week(const struct cal_control *ctl, int day,
 	else
 		year -= (month < MARCH) + 14;
 	if (ctl->reform_year < year
-	    || (year == ctl->reform_year && REFORMATION_MONTH < month)
-	    || (year == ctl->reform_year
-	    && month == REFORMATION_MONTH && 13 < day)) {
+	    || (year == ctl->reform_year && REFORM_MONTH < month)
+	    || (year == ctl->reform_year && month == REFORM_MONTH && 13 < day)) {
 		int64_t long_year = year;
 		return (long_year + (year / 4) - (year / 100) + (year / 400) +
 			reform[month - 1] + day) % DAYS_IN_WEEK;
 	}
 	if (year < ctl->reform_year
-	    || (year == ctl->reform_year && month < REFORMATION_MONTH)
-	    || (year == ctl->reform_year && month == REFORMATION_MONTH && day < 3))
+	    || (year == ctl->reform_year && month < REFORM_MONTH)
+	    || (year == ctl->reform_year && month == REFORM_MONTH && day < 3))
 		return (year + year / 4 + old[month - 1] + day) % DAYS_IN_WEEK;
 	return NONEDAY;
 }
@@ -964,8 +966,8 @@ static int week_number(int day, int month, int32_t year, const struct cal_contro
 	if (yday + fday < DAYS_IN_WEEK)
 		return week_number(31, DECEMBER, year - 1, ctl);
 
-	/* Or it could be part of the next year.  The reformation year had less
-	 * days than 365 making this check invalid, but reformation year ended
+	/* Or it could be part of the next year.  The reform year had less
+	 * days than 365 making this check invalid, but reform year ended
 	 * on Sunday and in week 51, so it's ok here. */
 	if (ctl->weektype == WEEK_NUM_ISO && yday >= 363
 	    && day_in_week(ctl, day, month, year) >= MONDAY

Re: [v2 PATCH 0/2] Pull Request

[J William Piggott]

Karel,

If you'd like --gregorian and --julian to mean exclusively using their
respective calendar system, then we could:

* change --iso to --gregorian and let the man page explain that it is proleptic.

* depreciate --julian in favor of --ordinal (--doy or --day-of-year). IMO, this
   should be done regardless.

* create a private --roma that is the complement to --gregorian; then after an
   appropriate mourning period change it to --julian and make it public.

RFC:
Can/should the new cal(1) options have short versions?

>From Documentation/howto-contribute.txt:
"... it is not recommended to add short command line options [to POSIX utils]
before they are part of the standard."

But most of cal(1)'s options already have short versions and the standard says
there are no options for cal(1).

If we use my above idea then --julian will have -j, so IMO --gregorian should
have -g. It would also be nice for --ordinal to have -o.