Perl Tk::Date - toggle by week - perl

Question

I am in the process of writing a GUI which will monitor if various measurements have been made on a weekly basis. I have written various other GUIs for updating measurements results each day onto a database. These GUIs use Tk::Date datewidget that allows me to toggle by days
my $datewidget = $f_filter->Date(-choices=>'today', -datefmt=>'%2d %2m %4y',
-fields=>'date', -varfmt=>'datehash',
-monthmenu=>1, -allarrows=>1,
-value=>'now', -command=>\&populate)->pack(-side=>'left');
This lets me use the up and down arrows to increment/decrement days, change months and year.
What I desire to do in the weekly GUI is have an up and down arrow that will toggle by week only. Eg this week would be 'Mon Nov 4 - Fri Nov 8', next week 'Mon Nov 11 to Fri Nov 15'
I would like to be able to go forwards and backwards several years.
Is there a simple way to do this in perl-Tk::Date or Date::Entry?

Answer 1

Tk::Date and Tk::DateEntry cannot do this out of the box. With Tk::Date, I can propose the following approach:
use -varfmt => 'unixtime' instead of datehash, because the latter does not work well with the ->configure(-value => ...) call used later
set -editable=>0 to remove all arrow buttons created by Tk::Date
create the inc/dec buttons yourself
and make the date calculations using DateTime (see the incweek subroutine here)
Something like the following could work:
use strict;
use Tk;
use Tk::Date;
my $mw = tkinit;
my $datewidget = $mw->Date(-choices=>'today', -datefmt=>'%2d %2m %4y',
-fields=>'date', -varfmt=>'unixtime',
-editable=>0,
-monthmenu=>1,
-value=>'now',
-command=>sub { warn "populate #_" })->pack(-side=>'left');
my $arrowframe = $mw->Frame->pack(-side => 'left');
{
no warnings 'once'; # because of INCBITMAP/DECBITMAP
$arrowframe->FireButton(-bitmap => $Tk::FireButton::INCBITMAP, -command => sub { incweek(+1) })->pack(-side => 'top');
$arrowframe->FireButton(-bitmap => $Tk::FireButton::DECBITMAP, -command => sub { incweek(-1) })->pack(-side => 'top');
}
MainLoop;
sub incweek {
my($inc) = #_;
use DateTime;
my $epoch = $datewidget->get;
my $dt = DateTime->from_epoch(epoch => $epoch);
$dt = $dt->add(weeks => $inc);
$datewidget->configure(-value => $dt->epoch);
}
__END__
Note that $datewidget->get returrns now the epoch time, but using DateTime you can easily convert this into y/m/d values.