simple grammar for dates

examples/dates/Dates.gf

@@ -0,0 +1,32 @@
+abstract Dates = {
+
+flags startcat = Date ;
+
+cat
+  Date ; Year ; Month ; Day ; Time ; Hour ; Minute ; Weekday ; Ampm ;
+
+fun
+  DFull : Year -> Month -> Day -> Weekday -> Time -> Date ;
+  
+  MkYear : Int -> Year ;
+
+  MJan, MFeb, MMar, MApr, MMay, MJun, MJul, MAug, MSep, MOct, MNov, MDec : Month ;
+
+  MkDay : Int -> Day ;
+
+  MkTime : Ampm -> Hour -> Minute -> Time ;
+
+  H01, H02, H03, H04, H05, H06, H07, H08, H09, H10, H11, H12 : Hour ;
+
+  MkMinute : Int -> Minute ;
+
+  WSun, WMon, WTue, WWed, WThu, WFri, WSat : Weekday ;
+
+  AM, PM : Ampm ;
+
+-- noncanonical ways
+
+  DToday, DYesterday, DTomorrow : Time -> Date ;
+
+}
+