Sven Van Caekenberghe wrote:
On 03 Sep 2014, at 15:24, Ben Coman <b...@openinworld.com> wrote:
Sven Van Caekenberghe wrote:
Hi Sean,
On 03 Sep 2014, at 00:32, Sean P. DeNigris
<s...@clipperadams.com>
wrote:
Sven Van Caekenberghe-2 wrote
Maybe you got the example and the input mixed up ?
Oh yeah, I did, but even the example in that case is ambiguous, no?
(ZTimestampFormat fromString: '02/03/01 (16:05:06)')
parse: '10/10/10 (12:01:01)'.
How does it decide whether it's American i.e. Feb 3rd, or European i.e. Mar 2nd?
No, it is not ambiguous. The positions in the pattern are not used to determine the meaning of the elements, only the values.
Okay, but its ambiguous in the sense that, at a glance, without knowing the legend (even though you provided it), at least Sean and myself got confused.
For me part of that confusion is that you said...
1=year
2=month
3=dayInMonth
4=hour (16 in 24 hour format)
5=minute
6=second
but the example used
02=month
03=day
No, it is not confusing: the rule is from largest to smallest unit, thus year, month, day, hour, minute and second. Which is the ISO 8601 representation order BTW, making the most scientific sense IMHO.
In either case, its harder to remember which magnitude an arbitrary index number refers, than using the usual mnemonics like this...
yy=year
mm=month
mmm=month name
d=day of month
dd=zero padded day of month
hh=12 hour
HH=24 hour
etc... and thats just off the top of my head. I think most people are familiar with this.
Alternatively, if you want to use numbers, the following would be more intuitive to anyone glancing at it without needing to know the legend.
99=year
12=month
31=day
24=24 hour
12=12 hour
60=minute
?=second.
etc...
btw, I missed the first part of the
For example, limited to date elements only:
(ZTimestampFormat fromString: '02/03/01') format: Date today. => '09/03/14'
(ZTimestampFormat fromString: '03/02/01') format: Date today. => '03/09/14'
(ZTimestampFormat fromString: 'Feb 3, 2001') format: Date today. => 'Sep 3, 2014'
(ZTimestampFormat fromString: '02-FEB-2001') format: Date today. => '09-SEP-2014'
(ZTimestampFormat fromString: 'Saturday, Februari 3 ''01') format: Date today. => 'Wednesday, September 3 ''14'
The reference date is 20010203 which was a Saturday, the recognised elements for dates are:
'2001' yearFourDigits
'01' yearTwoDigits
'02001' yearFull
'02' monthTwoDigits
'2' month
'February' monthNameCapitalized
'february' monthNameLowercased
'FEBRUARY' monthNameUppercased
'Feb' monthNameAbbreviatedCapitalized
'feb' monthNameAbbreviatedLowercased
'FEB' monthNameAbbreviatedUppercased
'3' day
'_3' dayTwoDigitsSpacePadded
'03' dayTwoDigits
See #formatSpecifications, each of those has parse and format methods, like #format:yearTwoDigitsOn: and #parseYearTwoDigitsFrom:
Sven
That interesting. With the call of #formatSpecifications from...
ZTimestampFormat class >> initialize
"Initialize this class, to be redone every time #formatSpecifications changes."
Formats := Dictionary newFromPairs: self formatSpecifications.
FormatKeys := Formats keys sorted: [ :x :y | x size >= y size ]
it looks like the format specifications could almost be pluggable. What if /Formats/ was instead an instance variable, such that my project could provide an extention method like this...
ZTimestampFormat class >> myFormatSpecifications
^ #(
'YYYY' yearFourDigits
'YY' yearTwoDigits
'MM' monthTwoDigits
'M' month
'Month' monthNameCapitalized
'month' monthNameLowercased
'MONTH' monthNameUppercased
'Mth' monthNameAbbreviatedCapitalized
'mth' monthNameAbbreviatedLowercased
'MTH' monthNameAbbreviatedUppercased
'D' day
'_D' dayTwoDigitsSpacePadded
'DD' dayTwoDigits
'h' hour12
'hh' hour12TwoDigits
'HH' hour24TwoDigits
'PM' daypartUppercased
'pm' daypartLowercased
'm' minute
'mm' minuteTwoDigits
's' second
'ss' secondTwoDigits
'Z' timeZoneZ
'+00:00' timeZone
'UTC' timeZoneAbbreviated
'UTCLong' timeZoneAbbreviatedLong
'Weekday' weekdayNameCapitalized
'weekday' weekdayNameLowercased
'WEEKDAY' weekdayNameUppercased
'Wday' weekdayNameAbbreviatedCapitalized
'wday' weekdayNameAbbreviatedLowercased
'WDAY' weekdayNameAbbreviatedUppercased )
so I could go something like...
(ZTimestampFormat withSpecification: #myFormatSpecification fromString: 'MM/DD/YY') format: Date today. => '09/03/14'
That would be coool!
cheers -ben
Yes, making it totally pluggable, or at least provide both an example based one and a more classic one makes sense. I'll think about that. Good idea.
But the whole concept of the example is that it is easy to remember. Or so it should be ;-)
btw, I didn't understand how yearFull in this line...
'02001' yearFull
was different from yearFourDigits.
Some people insist on the fact that using 4 digit years is wrong (http://longnow.org) ;-)
Thanks I understand. Now off-topic, I like this... "Our crowd curated
library of long-term thinking will be filled with the best 3,500
volumes to restart civilization."
I've sometimes had the urge to write a book on how to restart
civilization. A sort of real-life optimum path to producing the
pre-requisites to advance tech levels. The sort of thing you keep
under the bed that is no use until the day you need it...
For printing, 2001 and 02001 are the same because there is a natural overflow, but for parsing this is not the case: 02001 means using all digits until a non-digit, while 2001 always takes 4, and 01 always takes 2.
BTW, these specs are not perfectly deterministic/symmetrical. There are too many date/time formats and conventions.
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