+date ∷ Parser Day
+date = do day ← read2
+ _ ← char ' '
+ month ← shortMonthNameP
+ _ ← char ' '
+ year ← (+ 1900) <$> read2
+ _ ← char ' '
+ assertGregorianDateIsGood year month day
+
+-- |Parse the time and time zone of an RFC 822 date and time string.
+rfc822Time ∷ Parser (TimeOfDay, TimeZone)
+rfc822Time = do tod ← hms
+ _ ← char ' '
+ tz ← zone
+ return (tod, tz)
+
+hms ∷ Parser TimeOfDay
+hms = do hour ← read2
+ minute ← char ':' *> read2
+ second ← option 0 (char ':' *> read2)
+ assertTimeOfDayIsGood hour minute second
+
+zone ∷ Parser TimeZone
+zone = choice [ string "UT" *> return (TimeZone 0 False "UT" )
+ , string "GMT" *> return (TimeZone 0 False "GMT")
+ , char 'E'
+ *> choice [ string "ST" *> return (TimeZone ((-5) * 60) False "EST")
+ , string "DT" *> return (TimeZone ((-4) * 60) True "EDT")
+ ]
+ , char 'C'
+ *> choice [ string "ST" *> return (TimeZone ((-6) * 60) False "CST")
+ , string "DT" *> return (TimeZone ((-5) * 60) True "CDT")
+ ]
+ , char 'M'
+ *> choice [ string "ST" *> return (TimeZone ((-7) * 60) False "MST")
+ , string "DT" *> return (TimeZone ((-6) * 60) True "MDT")
+ , return (TimeZone ((-12) * 60) False "M")
+ ]
+ , char 'P'
+ *> choice [ string "ST" *> return (TimeZone ((-8) * 60) False "PST")
+ , string "DT" *> return (TimeZone ((-7) * 60) True "PDT")
+ ]
+ , char 'Z' *> return (TimeZone 0 False "Z")
+ , char 'A' *> return (TimeZone ((-1) * 60) False "A")
+ , char 'N' *> return (TimeZone ( 1 * 60) False "N")
+ , char 'Y' *> return (TimeZone ( 12 * 60) False "Y")
+ , read4digitsTZ
+ ]
+
+toAsciiBuilder ∷ ZonedTime → AsciiBuilder
+toAsciiBuilder zonedTime