sorting objects with "sort" and subroutine

From: Jay Eckles (j.eckles_at_computer.org)
Date: 11/27/04 

Date: 27 Nov 2004 10:55:56 -0800

I'm having some difficulty figuring out why a bit of code isn't
working. I'm hoping you can help.

I have a funciton that retuns an array of objects. I have defined the
class myself (the definition is below, it's quite short). I want to
sort that array, using a subroutine to define how the objects should
be sorted. Here's the line I use to call sort:

@events = sort calendar::timeCompare @events

Where calendar::timeCompare is the subroutine I've defined in a
package I called calendar.

The problem is that in timeCompare, I'm not able to access any of the
members of the objects $a and $b. For example,

package calendar ;
...
sub timeCompare{
   print STDERR "a when: $a->{'when'}\n" ;
   print STDERR "a summary: $a->{'summary'}\n" ;
...

gives me the following output:

a when:
a summary:

(I know that the object have values for 'when' and 'summary' because I
use the objects, after the sort call, and they have values).

Without access to these members, I can't sort the objects. Is there
any trick to sorting objects as opposed to scalar values?

Thanks for any assistance you can lend.

Jay Eckles

PS - here's the class definition:

###Event class
package Event ;

sub new {
   my($class) = shift;

   bless {
      "date" => undef,
      "when" => undef,
      "location" => undef,
      "summary" => undef,
      "details" => undef
   }, $class;
}

PPS - this is part of an open source project called CGI Calendar,
http://sourceforge.net/projects/cgicalendar

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