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Re: date and time formatting

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David Storrs
May 31, 2005 11:12
Re: date and time formatting
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On May 31, 2005, at 1:16 PM, Rob Kinyon wrote:

>>> What's wrong with porting DateTime?
>> It's back to the old question of "what's in core?"  Are dates and
>> times something that are used in such a large proportion of programs
>> that they deserve to be shipped in the basic grammar?  Or perhaps in
>> the basic set of packages?
>> Perl 5 has an entire swath of modules designed to manipulate dates
>> and times; this suggests that they are (A) commonly used and (B)
>> something that people feel very strongly about the semantics of.
> Which still begs the question - why not port DateTime to P6? Why can't
> installing a module provide new keywords?
> Rob

In reverse order:

- No reason it can't.  Nor did I imply otherwise.

- I didn't say we shouldn't port DateTime.  My point was simply that,  
based on the amount of date-related code on CPAN, this is an issue  
that many people care about quite a bit.  We would probably be well  
served to consider it carefully and decide on what semantics we  
really want.  Maybe DateTime is exactly what everyone wants and all  
we need to do is port it.  On the other hand, there is something to  
be said for Nathan's approach; isn't it worth discussing?

Personally, I've always found date handling to be difficult.  The  
various modules go a long way towards simplifying it, but they  
require calling functions and methods, which forces one to think in a  
low-level algorithmic style.   It would be great if there was a more  
intuitive time/date handling model built into the language...the kind  
of quantum leap in power and intuitiveness that we got from the new  
Rules engine (as opposed to the old regex engine).

Perhaps something like the typed operations that were discussed  

     my ($launch_date = now() + 6 weeks) but time(9am);
     say "We will launch on a $lauch_date.day_of_week, at  
     say "This gives us " . $launch_date but hours . " hours,  
including weekends and evenings.";

     #  outstanding_tickets() returns user-written ticket objects;  
created() returns a time object representing
     #  creation time.  The objects stringify to their report.
     say "Remaining issues, oldest first:";
     say "\t $_" for sort { $a.creation().age <=> $b.creation().age }  

     #  Prints 'Meetings Sunday, June 19.;
     say "Meetings are the third Sunday of each month.  The first  
June meeting is " .
         (month(6).days(0))[2] but format(/<dayname>, <monthname>  

The above examples are just noodlings and are not well thought out,  
but hopefully they point in the right direction.


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