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

so i wanted to do some work with hash-references. nothing easier than that: 
my %list = { 'lang' => 'de' };
my $listref = \%list;
print $listref->{'lang'};

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should print something like
HASH(0x1fc0e)

that's what i thought too. but then, i got an error saying 
Not a HASH reference at ...

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debugging tells me, that $listref contains REF(0x80bf20). after doing some research, i got to know that REF(...) is a 'destination of a reference', not the reference itself.
so: thank you guys for any help.
(i do use -w and use strict. )

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Re: REF instead of HASH-ref
by VSarkiss (Monsignor) on Sep 14, 2004 at 22:05 UTC

    my %list = { 'lang' => 'de' };
    You want: 
    my %list = ( 'lang' => 'de' );
my $listref = \%list;

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    (Note the parens).

    Or you can do my $listref = { 'lang' => 'de' };(Note the curly braces).

    Once you do that, print $listref->{'lang'} should print de, not any kind of stringified hash.

    Check out perlref for more detail. Basically, the parenthese produce a list (which you can assign to a hash and then take a reference), and the curly braces produce an anonymous hash, whose reference you can store in a scalar.

    Update
    Added a little more detail....

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      if i do 
      my %list = ( 'lang' => 'de' );
my $listref = \%list;
print ref($listref);

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      i get REF. if i do 
      my $listref = { 'lang' => 'de' };
print ref($listref);

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      i get HASH.

      i use this with CGI. so i initialize the hash as follow: 
      use vars qw($query @parname %list $n );

$query = new CGI;
@parname = $query->param;
foreach $n (@parname) {
   $list{$n} = $query->param($n);
}

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      i then just pass \%list along to a function which takes the refenrence and uses the hash again. i used exactly this code (copy/paste) in another app, there it worked fine. the environment is the same, too.

      kind of puzzled. update: if i update the initialization to: 
      $query = new CGI;
@parname = $query->param;
foreach $n (@parname) {
  $hashref->{$n} = $query->param($n);
}

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      everything works fine. hm...
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