code review 181130: First pass at a new interface.

New time formatter, time.Format(formatString)
The model is that formatString is a a representation of a standard time,
and that Format converts the time to that representation.
Standard representaitons are defined for ANSIC, RFC850, RFC1123, and ISO8601.
There's also a humane Kitchen fomat: 3:04PM.

[r, 2010-01-05 06:21:16]

Hello rsc (cc: golang-dev@googlegroups.com),

I'd like you to review the following change.

[benolive, 2010-01-05 14:42:22]

On 2010/01/05 06:21:16, r wrote:
> Hello rsc (cc: mailto:golang-dev@googlegroups.com),
> 
> I'd like you to review the following change.

The ISO8601 'Z' is not a constant. It is Z for UTC and the offset in zulu for
everything else (eg 1994-09-17T20:04:26-0500).

Also, it seems to me this should be callable on a `Time` for when you already
have the parsed time.

[rsc, 2010-01-05 16:42:02]

very nice!

http://codereview.appspot.com/181130/diff/1/3
File src/pkg/time/format.go (right):

http://codereview.appspot.com/181130/diff/1/3#newcode13
src/pkg/time/format.go:13: const (
// doc comment

http://codereview.appspot.com/181130/diff/1/3#newcode17
src/pkg/time/format.go:17: ISO8601 = "2006-01-02T15:04:05Z"
This should be ...15:04:05-08:00 and then
if the ZoneOffset == 0 print "Z" instead of "±hh:mm".

http://www.ietf.org/rfc/rfc3339.txt has details.

http://codereview.appspot.com/181130/diff/1/3#newcode25
src/pkg/time/format.go:25: StdLongMonth   = "January"
I'd be inclined to hide these in favor of a doc comment on Format (stdMonth,
etc.).
I worry that people will think they should write

StdMonth+" "+StdWeekDay+" "+...

http://codereview.appspot.com/181130/diff/1/3#newcode35
src/pkg/time/format.go:35: StdHourZero12  = "03"
StdZeroHour12?

http://codereview.appspot.com/181130/diff/1/3#newcode86
src/pkg/time/format.go:86: func Format(layout string, ns int64) string {
func (t *Time) Format(layout string) string {

http://codereview.appspot.com/181130/diff/1/4
File src/pkg/time/time.go (right):

http://codereview.appspot.com/181130/diff/1/4#newcode231
src/pkg/time/time.go:231: var longDayNames = []string{
maybe move here down over to format.go
(and delete the format func)

http://codereview.appspot.com/181130/diff/1/4#newcode379
src/pkg/time/time.go:379: // Asctime formats the parsed time value in the style
of
I'm inclined to toss these in favor of clients writing

t.Format(time.Asctime)
t.Format(time.RFC850)
etc

[r2, 2010-01-06 01:16:20]

PTAL

[cw, 2010-01-06 02:27:31]

I really like the way this looks.

[r2, 2010-01-06 02:39:58]

Thanks. I'm pretty happy with the interface.

-rob

[rsc, 2010-01-06 15:56:49]

http://codereview.appspot.com/181130/diff/7/9
File src/pkg/time/format.go (right):

http://codereview.appspot.com/181130/diff/7/9#newcode13
src/pkg/time/format.go:13: // These are predefined formats for use in
Time.Format().
s/()//

http://codereview.appspot.com/181130/diff/7/9#newcode142
src/pkg/time/format.go:142: func (t *Time) Format(layout string) string {
// Format returns a string version of t formatted according to layout.
// ...

http://codereview.appspot.com/181130/diff/7/10
File src/pkg/time/time.go (left):

http://codereview.appspot.com/181130/diff/7/10#oldcode381
src/pkg/time/time.go:381: func (t *Time) String() string { return format(t, "%a
%b %e %H:%M:%S %Z %Y") }
I'd like to keep the String method for printing.

[r2, 2010-01-06 23:00:53]

PTAL

[rsc, 2010-01-06 23:09:21]

LGTM

update CL desc before submit

http://codereview.appspot.com/181130/diff/17/1020
File src/pkg/time/time_test.go (right):

http://codereview.appspot.com/181130/diff/17/1020#newcode143
src/pkg/time/time_test.go:143: // The numeric time represents Tue Jan  5
16:00:57 EST 2010
should be different in every respect from the layout date, so not january. 
suggest += 31*86400 = 1265346057

[rsc, 2010-01-06 23:23:03]

LGTM

http://codereview.appspot.com/181130/diff/23/1027
File src/pkg/time/time_test.go (right):

http://codereview.appspot.com/181130/diff/23/1027#newcode143
src/pkg/time/time_test.go:143: // The numeric time represents Fri Feb  5
16:00:57 EST 2010
Thu Feb  4 21:00:57 PST 2010

(matches the formats above)

[r, 2010-01-06 23:32:57]

*** Submitted as http://code.google.com/p/go/source/detail?r=9d7826e01636 ***

New time formatter, time.Format(formatString)
The model is that formatString is a a representation of a standard time,
and that Format converts the time to that representation.
Standard representaitons are defined for ANSIC, RFC850, RFC1123, and ISO8601.
There's also a humane Kitchen fomat: 3:04PM.

R=rsc, benolive, cw
CC=golang-dev
http://codereview.appspot.com/181130