undefined value as a HASH reference??

ryddler has asked for the wisdom of the Perl Monks concerning the following question:

Fellow monks,
I seek your wisdom with the following problem. I have created a package with a single sub that I call from the main script. I pass a reference to a hash structure that is built in the main script to the sub when it is called. The hash is built like this:

$vars = {
    'script'    => "template.pl",
    'filenumber'    => $filenumber,
    'results'    => $results_hash_ref,
};
[download]

and is passed like this:

ATGF::PDF::Charges::write_excel($vars);
[download]

The error I am receiving is "Can't use an undefined value as a HASH reference at C:/projects/metrosearch//ATGF/PDF/Charges.pm line 47."
Here's a snippet of the sub:

sub write_excel {
    my $var_ref = shift;
    #print_debug(Dumper $var_ref);
    my $Excel = Win32::OLE->new('Excel.Application', 'Quit')
        or die Win32::OLE->LastError;

    $Excel->{Visible} = 1;

    my $Book = $Excel->Workbooks->Open(
    # Filename,[UpdateLinks],[ReadOnly],[Format],[Password],[WriteResP
+assword],
    # [IgnoreReadOnlyRecommended],[Origin],[Delimiter],[Editable],[Not
+ify],[Converter],[AddToMru]
        $ExcelFile,undef,0,undef,undef,undef, 
        undef,undef,undef,undef,0,undef,0
    );

    my $Sheet = $Book->Worksheets(1);

    # Subject Property Column
    my $address  = "$var_ref->{results}{'Street'}\n";
    $address    .= "$var_ref->{results}{'Street2'}\n" if (length($var_
+ref->{results}{'Street2'}) > 0 );
    $address    .= "$var_ref->{results}{'City'}, " if (length($var_ref
+->{results}{'City'}) > 0 );
    $address    .= "$var_ref->{results}{'State'} " if (length($var_ref
+->{results}{'State'}) > 0 );
    $address    .= "$var_ref->{results}{'Zip5'}" if ($var_ref->{result
+s}{'Zip5'} != 0 );
    $address    .= "-$var_ref->{results}{'Zip4'}" if ($var_ref->{resul
+ts}{'Zip4'}!= 0 );
    
    $Sheet->Range("A3")->{'Value'}  = $address;
    ##########################################################
    # line 47 from error message above is the following line #
    ##########################################################
    $Sheet->Range("A6")->{'Value'}  = $var_ref->{results}{'Legal'};
    $Sheet->Range("B8")->{'Value'}  = $var_ref->{results}{'PIN'};
    $Sheet->Range("B9")->{'Value'}  = $var_ref->{results}{'PIN2'};
    $Sheet->Range("B10")->{'Value'} = $var_ref->{results}{'PIN3'};
    ...
}
[download]

As stated in the above snippet, this line: $Sheet->Range("A6")->{'Value'} = $var_ref->{results}{'Legal'}; is the offending line (as are most of the rest below it if I comment them out one by one). However, if I were to modify it like so.

my $legal = $var_ref->{results}{'Legal'};
$Sheet->Range("A6")->{'Value'}  = $legal;
[download]

It works just fine. I don't understand why these are different in any other way than the style in which they are written. Can anyone shed some light on this for me?
TIA
ryddler

Comment on undefined value as a HASH reference?? Select or Download Code

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Re: undefined value as a HASH reference?? by the_0ne (Pilgrim) on May 16, 2001 at 18:35 UTC
I think people are missing the point. The poster is saying why when you use the hashref to set a value in the sheet range you get the error, but if you use the same hashref to set to a simple scalar ($legal) and then use that same scalar to set the sheet range there is no error. I'm a little lost on that one myself and the Hash problem post does not answer this question. Not sure what the difference is.	[reply]
Re: undefined value as a HASH reference?? by azatoth (Curate) on May 16, 2001 at 18:06 UTC
`use warnings;` and see Hash Problem. UPDATE : Looks like i misunderstood this question Azatoth a.k.a Captain Whiplash Make Your Die Messages Full of Wisdom! Get YOUR PerlMonks Stagename here! Want to speak like a Londoner?	[reply] [d/l]
Re: Re: undefined value as a HASH reference?? by ryddler (Monk) on May 16, 2001 at 18:20 UTC
I did see that posting, but it doesn't answer my question. If you notice in my post I have given two examples of the offensive line, one of which works, and the other doesn't. Both are making assignments to something on the left side, but one causes an error, and the other doesn't. My question asks why the two are different, because it doesn't make any sense to me. I tried using the `use warnings;` and `use diagnostics` in my script (I already had -w), but the output results didn't give any more significant information that I could use. If I use the line that is commented out, `#print_debug(Dumper $var_ref);` I get a full printout showing all the variables to be quite defined! ryddler	[reply] [d/l] [select]
Re: undefined value as a HASH reference?? by knobunc (Pilgrim) on May 16, 2001 at 18:23 UTC
What does the `Dumper($var_ref)` call that you have commented out print? Maybe I haven't had enough coffee this morning, but it looks like the `results` element of `$var_ref` is not defined. -ben	[reply]
Re: Re: undefined value as a HASH reference?? by ryddler (Monk) on May 16, 2001 at 18:33 UTC
That's what my first thoughts were, and why I made that call in the first place, but here's what you'd see in the printout... $VAR1 = { 'filenumber' => '01-0052', 'results' => { 'Legal' => 'my lawyer made me do it', 'PriorpolDate' => undef, 'BldgLine' => undef, 'Deaths' => undef, 'Status' => 'OPEN', 'SearchType' => 'test', 'Notes' => 'this is where notes go…', 'Restrictions' => 'no restrictions', 'State' => 'IL', 'PIN2' => 'pin2yadayada', 'PIN3' => undef, 'City' => 'Champaign', 'LandVal' => '', 'SearchFromDate' => '2001-01-05 16:45:00', 'Drainage' => '1', 'Township' => 'village of champaign', 'EffectiveDate' => '2001-01-30 11:30:00', 'ImprovementVal' => '', 'Street' => '2408 Some Place', 'FileNumber' => '01-0052', 'Zip4' => '1234', 'Zip5' => '12345', 'OrderedBy' => undef, 'SearchedBy' => undef, 'MemberNumber' => '1234', 'Plat' => undef, 'LotSize' => 'a little bit smaller', 'Street2' => 'test street2', 'Easements' => undef, 'Exemptions' => '', 'Divorce' => undef, 'RequestDate' => '2001-01-30 11:30:00', 'MemberName' => 'W. Ghost Ryder', 'Probate' => undef, 'Wills' => undef, 'PIN' => 'assadsa', 'Access' => '100 feet of shoreline', 'TotalVal' => '' }, 'script' => 'template.pl', }; [download] ryddler	[reply] [d/l]
Re: Re: Re: undefined value as a HASH reference?? by knobunc (Pilgrim) on May 16, 2001 at 18:48 UTC
Is it possible that the `Range("A6")` call is returning undef? Hoewver, that does not explain why it works after you assign it to a scalar. Perhaps the thing returned by `Range()` is a tied hash? Can you print out the result of the following: `my $range = $Sheet->Range("A6"); print STDERR "Ref: ", ref($range), "\n"; print STDERR "Tied: ", tied($range), "\n";` [download] -ben	[reply] [d/l]
Re: Re: Re: Re: undefined value as a HASH reference?? by ryddler (Monk) on May 16, 2001 at 19:19 UTC
More Info: Re: undefined value as a HASH reference?? by ryddler (Monk) on May 17, 2001 at 18:07 UTC
Further investigation reveals that running the script from the command-line (passing the CGI params) runs without problems. The assignment is made without fail. So now the situation becomes even more bizarre. It would seem that the failure to assign directly from the hash is because of security levels. That didn't seem to make any sense, because an assignment could still be made from a scalar, so what's the problem? On a hunch, I removed the -T from the Perl configuration in IIS, and tried the script again. This time it ran without any errors. I don't know much about Taint mode, but it seems to have been the reason for the assignment failures even though the error message said absolutely nothing about any tainted variables. "Undefined value as a HASH reference" doesn't seem even remotely close to tainted variables to me. Does any of this make sense to anyone? If so, could you fill me in? ryddler	[reply]