time: add RFC1123 with numeric timezone format

Fixes #841.

R=rsc, r
CC=golang-dev
https://golang.org/cl/5322058

src/pkg/time/format.go

@@ -45,12 +45,12 @@ const (
 	UnixDate = "Mon Jan _2 15:04:05 MST 2006"
 	RubyDate = "Mon Jan 02 15:04:05 -0700 2006"
 	RFC822   = "02 Jan 06 1504 MST"
-	// RFC822 with Zulu time.
-	RFC822Z = "02 Jan 06 1504 -0700"
-	RFC850  = "Monday, 02-Jan-06 15:04:05 MST"
-	RFC1123 = "Mon, 02 Jan 2006 15:04:05 MST"
-	RFC3339 = "2006-01-02T15:04:05Z07:00"
-	Kitchen = "3:04PM"
+	RFC822Z  = "02 Jan 06 1504 -0700" // RFC822 with numeric zone
+	RFC850   = "Monday, 02-Jan-06 15:04:05 MST"
+	RFC1123  = "Mon, 02 Jan 2006 15:04:05 MST"
+	RFC1123Z = "Mon, 02 Jan 2006 15:04:05 -0700" // RFC1123 with numeric zone
+	RFC3339  = "2006-01-02T15:04:05Z07:00"
+	Kitchen  = "3:04PM"
 	// Handy time stamps.
 	Stamp      = "Jan _2 15:04:05"
 	StampMilli = "Jan _2 15:04:05.000"

src/pkg/time/time_test.go

@@ -201,6 +201,7 @@ var formatTests = []FormatTest{
 	{"RFC822", RFC822, "04 Feb 09 2100 PST"},
 	{"RFC850", RFC850, "Wednesday, 04-Feb-09 21:00:57 PST"},
 	{"RFC1123", RFC1123, "Wed, 04 Feb 2009 21:00:57 PST"},
+	{"RFC1123Z", RFC1123Z, "Wed, 04 Feb 2009 21:00:57 -0800"},
 	{"RFC3339", RFC3339, "2009-02-04T21:00:57-08:00"},
 	{"Kitchen", Kitchen, "9:00PM"},
 	{"am/pm", "3pm", "9pm"},
@@ -240,6 +241,7 @@ var parseTests = []ParseTest{
 	{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 -0800 2010", true, true, 1, 0},
 	{"RFC850", RFC850, "Thursday, 04-Feb-10 21:00:57 PST", true, true, 1, 0},
 	{"RFC1123", RFC1123, "Thu, 04 Feb 2010 21:00:57 PST", true, true, 1, 0},
+	{"RFC1123Z", RFC1123Z, "Thu, 04 Feb 2010 21:00:57 -0800", true, true, 1, 0},
 	{"RFC3339", RFC3339, "2010-02-04T21:00:57-08:00", true, false, 1, 0},
 	{"custom: \"2006-01-02 15:04:05-07\"", "2006-01-02 15:04:05-07", "2010-02-04 21:00:57-08", true, false, 1, 0},
 	// Optional fractional seconds.
@@ -248,6 +250,7 @@ var parseTests = []ParseTest{
 	{"RubyDate", RubyDate, "Thu Feb 04 21:00:57.012 -0800 2010", true, true, 1, 3},
 	{"RFC850", RFC850, "Thursday, 04-Feb-10 21:00:57.0123 PST", true, true, 1, 4},
 	{"RFC1123", RFC1123, "Thu, 04 Feb 2010 21:00:57.01234 PST", true, true, 1, 5},
+	{"RFC1123Z", RFC1123Z, "Thu, 04 Feb 2010 21:00:57.01234 -0800", true, true, 1, 5},
 	{"RFC3339", RFC3339, "2010-02-04T21:00:57.012345678-08:00", true, false, 1, 9},
 	// Amount of white space should not matter.
 	{"ANSIC", ANSIC, "Thu Feb 4 21:00:57 2010", false, true, 1, 0},