[project @ Provide support for formatting the day as an ordinal (e.g.…

… 1st, 22nd)]

doc/local-time.texinfo

@@ -584,6 +584,8 @@ FORMAT is a list containing one or more of strings, characters, and keywords.  S
 *microseconds
 @item :nsec
 *nanoseconds
+@item :ordinal-day
+day of month as an ordinal (e.g. 1st, 23rd)
 @item :long-weekday
 long form of weekday (e.g. Sunday, Monday)
 @item :short-weekday

src/local-time.lisp

@@ -1512,6 +1512,21 @@ elements."
                         (* (or offset-minute 0) 60))
                      offset))))))
 
+(defun ordinalize (day)
+  "Return an ordinal string representing the position of DAY in a sequence (1st, 2nd, 3rd, 4th, etc)."
+  (declare (type (integer 1 31) day))
+  (flet ((suffix ()
+           (if (<= 11 day 13)
+               "th"
+               (multiple-value-bind (quotient remainder) (floor day 10)
+                 (declare (ignore quotient))
+                 (case remainder
+                   (1 "st")
+                   (2 "nd")
+                   (3 "rd")
+                   (t "th"))))))
+    (format nil "~d~a" day (suffix))))
+
 (defun %construct-timestring (timestamp format timezone)
   "Constructs a string representing TIMESTAMP given the FORMAT of the string and the TIMEZONE.  See the documentation of FORMAT-TIMESTRING for the structure of FORMAT."
   (declare (type timestamp timestamp)
@@ -1550,6 +1565,8 @@ elements."
              (princ (1+ (mod (1- hour) 12)) result))
             ((eql fmt :ampm)
              (princ (if (< hour 12) "am" "pm") result))
+            ((eql fmt :ordinal-day)
+             (princ (ordinalize day) result))
             ((or (stringp fmt) (characterp fmt))
              (princ fmt result))
             (t

tests/tests.lisp

@@ -252,7 +252,21 @@
 
       "04:03"
       (format-timestring nil test-timestamp
-                         :format '((:hour 2) #\: (:min 2))))))
+                         :format '((:hour 2) #\: (:min 2)))
+
+      "5th"
+      (format-timestring nil test-timestamp
+                         :format '(:ordinal-day)))))
+
+(test format-timestring/ordinals
+  (flet ((format-ordinal (day)
+           (format-timestring nil (encode-timestamp 0 0 0 0 day 1 2008)
+                              :format '(:ordinal-day))))
+    (is-every string=
+      "31st" (format-ordinal 31)
+      "11th" (format-ordinal 11)
+      "22nd" (format-ordinal 22)
+      "3rd" (format-ordinal 3))))
 
 (test format-timestring/errors
   (with-output-to-string (*standard-output*)