Uncaught exception from user code:
	Can't call method "walk" on unblessed reference at treewalk.pl line 28.
	main::walk('ARRAY(0x15b220)') called at treewalk.pl line 34


##</code><code>##


#!/bin/env perl

use strict;
use warnings;
use diagnostics;


my $tree = 
  [
   "Accomplishments in the past week" => 'accomplishments.txt',
   "Plans for the next week"          =>
   [
    General   => 'plans.txt',
    Vacations => 'vacations.txt',
    Classes   => 'classes.txt'
   ],
   "Outstanding issues"               => 'issues.txt'
  ];


sub walk {
  my $t = shift ;

  while (my ($key, $val) = splice @$t, 0, 2) {
    if (!ref($val)) {
      print "$key => $val\n";
    } else {
      walk $val; ##### PROBLEM LINE
    }
  }

}
 
walk $tree;