in reply to Re: Re: dereferencing syntax Re: Getting keys/values from a referenced hash
in thread Getting keys/values from a referenced hash

Hi Andy!

I found out now (using Dumper-mod) that my reference to the nested hash is undefined (but only when I use use strict;)
When I don't use strict the reference ($results) holds all the data I want and is dumped correctly. Here's the way I get the nested hash from a file (the only possibility I have):

my $filename = $ARGV[0];
open (_filehandle_, "<$filename") or die "Meeeeep! $filename does not 
+exist!\n";
my @file = <_filehandle_>;
close (_filehandle_);
my $line = join "", @file;
my $results = eval ($line);
print '$results: '.Dumper($results);
my $colpattern = $results->{"col_pattern"};

[download]

That's pretty straight and ineffective code, but I better first try how things work and squeeze it up later then. ;-)
The fact that $results is undef tells me sth. goes wrong with eval().
Can it be that the use strict-statement affects or somehow impairs the evaluation of the file's contents (which is in $line now)?

Greetz, Micha

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Re: Re: dereferencing stuff
by blakem (Monsignor) on Nov 28, 2001 at 18:26 UTC
    Looks like the code you are evaling isn't strict compatible. You should check the value of $@ right after your eval. For instance, try this script with and without strict: 
    #!/usr/bin/perl -wT
use strict;

my $c;
my $code = '$global = 10; $c = 6';
eval $code;
die $@ if $@;
print "\$c = $c\n";

__END__

=head1 OUTPUT with strict
Global symbol "$global" requires explicit package name at (eval 1) lin
+e 1.

=head2 OUTPUT w/o strict
$c = 6

    [download]
    Also, your slurp-and-eval would be cleaner as a require or a do instead.

    -Blake

[reply]
[d/l]
      Seems to be the code from that file to be the error:

      Global symbol "$res_g2" requires explicit package name at (eval 2) line 1.

      Var $res_g2 holds the nested array I need to evaluate. Since I have no influence on the code written to the file I think I have to live without strict for that part.
      Thanks a lot!

      Micha

[reply]
[d/l]
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        Looks like you've got two options at this point. The first is just to turn strict off around that block: 
        { 
  no strict;
  eval $code;
}

        [download]
        Or you can attempt to pick off the errors one at a time, outside the eval; 
        my $res_g2;
eval $code;
die $@ if $@;

        [download]
        I'd recommend seeing how far you can get with the second method, though its quite possible that you'll encounter an error that cant be fixed in this manner.

        -Blake

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[d/l]
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