use Spreadsheet::ParseExcel::Simple;

my $xls = Spreadsheet::ParseExcel::Simple->read('excel.xls');
foreach my $sheet ($xls->sheets) {

  #unmerge
  unmerge($sheet->{sheet});
  

  while ($sheet->has_data) {  
    my @data = $sheet->next_row;
    print join("\t", @data),"\n";
  }
}


sub unmerge{
    my($oWkS) =@_;
    print "--------- SHEETNAME:", $oWkS->{Name}, "\n";

    my $range = $oWkS->get_merged_areas();
    for (@$range){
        print "
        start row : $_->[0]
        start col : $_->[1]
        end row   : $_->[2]
        end col   : $_->[3] \n\n";
        
        $oWkC = $oWkS->{Cells}[$_->[0]][$_->[1]];

        for my $iR ($_->[0] .. $_->[2]){
            for my $iC ($_->[1] .. $_->[3]){
                next if ($iR eq $_->[0] &&  $iC eq $_->[1]);
                print "SET [$iR][$iC] <= [$_->[0]][$_->[1]]\n";
                $oWkS->{Cells}[$iR][$iC]->{_Value} = $oWkC->Value;
            }
        }
    }
    print "--------- DONE Unmerging.\n";
}
[download]

Output:

--------- SHEETNAME:Sheet1

                start row : 0
                start col : 0
                end row   : 2
                end col   : 0 

SET [1][0] <= [0][0]
SET [2][0] <= [0][0]
--------- DONE Unmerging.
cat     Fluffy
cat     Vera
cat     Manxie
[download]

Caveat: The {_Value} is still not guaranteed to be in the topleft cell from a range (as misterperl had it in the second column), so the code might need to be expanded to first SEARCH for a defined {_Value} in the range. Then have that as the source data cell, then iterate over the range writing all other cells that are undefined...

You can access the functions from within Simple like:

$sheet->{sheet}->get_merged_areas();

# fill in merged cells
  my $ma = $page->{sheet}->{MergedArea};
  for my $a ( @$ma ) {
   my ( $tr, $lc, $br, $rc ) = @$a;
# propogate values top left to bottom right
  my $p = $page->{sheet}->{Cells}->[$tr]->[$lc]->{Val};
  for ( my $row=$tr; $row<=$br; $row++ ) {
   for ( my $col=$lc; $col<=$rc; $col++ ) {
    $page->{sheet}->{Cells}->[$row]->[$col]->{Val}=$p;
   }
  }
} # for $a
[download]

Ah, when I was reading the code, I found this explanation about Val and _Value in ~/perl5/lib/perl5/Spreadsheet/ParseExcel/Cell.pm

############################################################
#
# value()
#
# Returns the formatted value of the cell.
#
sub value {

    my $self = shift;

    return $self->{_Value};
}

############################################################
#
# unformatted()
#
# Returns the unformatted value of the cell.
#
sub unformatted {

    my $self = shift;

    return $self->{Val};
}

############################################################
[download]

You see, sometimes a cell has a formula, and it holds the formula string, but also a resulting value. So Val holds =sum(A1+1) and _Value holds "42". It was/is? a problem in a XLS writer module, where only one was filled in, so you were required to open the spreadsheet in excel, let it calculate the values, then save it again in order to keep on processing the sheet.

my @row=$page->next_row;
[download]

Yet if I inspect the cell Val at the row and col, they are all correct. So I had to manually push values into the array:

for ( my $c=0; $c<=$maxCol; $c++ ) {
 next if $row[$c] =~ /./;
 $row[$c]=$page->{sheet}->[$row]->[$c]->{Val};
}
[download]

See also previous explanation:

The perl module uses the function Value() to retrieve the value from the variable {_Value}. So setting {Val} will not work with next_row().

sub next_row {
  map { $_ ? $_->Value : "" } @{$_[0]->{sheet}->{Cells}
}
[download]

Now, because a spanned cell COULD hold a value() BEFORE spanning (usually empty, but not necessarily), you will get that value() instead of the spanned value...

spanning is like mounting a drive over a directory that may already hold files.... but it works now, congrats!