Date manipulation: Difference between revisions

=={{header|Fōrmulæ}}==

In [https://wiki.formulae.org/Date_manipulation this] page you can see the solution of this task.

Fōrmulæ programs are not textual, visualization/edition of programs is done showing/manipulating structures but not text ([http://wiki.formulae.org/Editing_F%C5%8Drmul%C3%A6_expressions more info]). Moreover, there can be multiple visual representations of the same program. Even though it is possible to have textual representation —i.e. XML, JSON— they are intended for transportation effects more than visualization and edition.

The option to show Fōrmulæ programs and their results is showing images. Unfortunately images cannot be uploaded in Rosetta Code.

=={{header|Perl 6}}==

Perl 6 comes with a build-in DateTime type

to support most aspects of standard civic time calculation

that are not dependent on cultural idiosyncracies. <br>

Unfortunately, Perl 6 does not yet have a date parsing module

(mostly due to a reticence to inflict Western cultural imperialism on other cultures...

or maybe just due to laziness), but that just gives us another opportunity to demonstrate the built-in grammar support.

<lang perl6>my @month = <January February March April May June July August September October November December>;

my %month = flat (@month Z=> ^12), (@month».substr(0,3) Z=> ^12), 'Sept' => 8;

grammar US-DateTime {

rule TOP { <month> <day>','? <year>','? <time> <tz> }

token month {

(\w+)'.'? { make %month{$0} // die "Bad month name: $0" }

}

token day { (\d ** 1..2) { make +$0 } }

token year { (\d ** 1..4) { make +$0 } }

token time {

(\d ** 1..2) ':' (\d ** 2) \h* ( :i <[ap]> \.? m | '' )

{

my $h = $0 % 12;

my $m = $1;

$h += 12 if $2 and $2.substr(0,1).lc eq 'p';

make $h * 60 + $m;

}

}

token tz { # quick and dirty for this task

[

| EDT { make -4 }

| [ EST| CDT] { make -5 }

| [ CST| MDT] { make -6 }

| [ MST| PDT] { make -7 }

| [ PST|AKDT] { make -8 }

| [AKST|HADT] { make -9 }

| HAST

]

}

}

$/ = US-DateTime.parse('March 7 2009 7:30pm EST') or die "Can't parse date";

my $year = $<year>.ast;

my $month = $<month>.ast;

my $day = $<day>.ast;

my $hour = $<time>.ast div 60;

my $minute = $<time>.ast mod 60;

my $timezone = $<tz>.ast * 3600;

my $dt = DateTime.new(:$year, :$month, :$day, :$hour, :$minute, :$timezone).in-timezone(0);

$dt = $dt.later(hours => 12);

say "12 hours later, GMT: $dt";

say "12 hours later, PST: $dt.in-timezone(-8 * 3600)";</lang>

{{out}}

<pre>12 hours later, GMT: 2009-02-08T12:30:00Z

12 hours later, PST: 2009-02-08T04:30:00-0800</pre>