code review 833045: time: do not segment time strings by character class.

time: do not segment time strings by character class.
instead use pure substring matching to find template values.

this makes stdZulu unnecessary and allows formats
like "20060102 030405" (used in some internet protocols).

this makes Parse not handle years < 0000 or > 9999 anymore.
that seems like an okay price to pay, trading hypothetical
functionality for real functionality.

also changed the comments on the Time struct to use the
same reference date as the format and parse routines.

[rsc, 2010-03-30 21:11:59]

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

I'd like you to review this change.

[r2, 2010-03-30 21:21:46]

s/us/use/ in CL description

[r, 2010-03-30 21:27:14]

http://codereview.appspot.com/833045/diff/2001/3001
File src/pkg/time/format.go (right):

http://codereview.appspot.com/833045/diff/2001/3001#newcode360
src/pkg/time/format.go:360: for len(prefix) > 0 && prefix[0] == ' ' {
i think this code could be less fiddly if you moved the space-trimming piece to 
a separate function. then two function calls establish the initial space string
and you have the final if.

http://codereview.appspot.com/833045/diff/2001/3001#newcode396
src/pkg/time/format.go:396: // sane: hours in 0..23, minutes in 0..59, day of
month in 0..31, etc.
the new restrictions in years need to be told

(not sure i like them but i admit that real use trumps hypothetical use)

[rsc, 2010-03-30 21:35:57]

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

Please take another look.

[r, 2010-03-30 21:45:56]

LGTM with grumblings

http://codereview.appspot.com/833045/diff/9001/10001
File src/pkg/time/format.go (right):

http://codereview.appspot.com/833045/diff/9001/10001#newcode394
src/pkg/time/format.go:394: // Years must be in the range 0000..9999.
the CL description says 1000. one is wrong.

[rsc, 2010-03-30 21:54:13]

fixed CL description

[rsc, 2010-03-30 21:54:35]

*** Submitted as http://code.google.com/p/go/source/detail?r=d625c471c301 ***

time: do not segment time strings by character class.
instead use pure substring matching to find template values.

this makes stdZulu unnecessary and allows formats
like "20060102 030405" (used in some internet protocols).

this makes Parse not handle years < 0000 or > 9999 anymore.
that seems like an okay price to pay, trading hypothetical
functionality for real functionality.

also changed the comments on the Time struct to use the
same reference date as the format and parse routines.

R=r
CC=golang-dev
http://codereview.appspot.com/833045