#! /usr/bin/perl
use strict;
use warnings;
use 5.010.000;

my $data = {
        foo => [
                { bar => 123 },
        ],
};

# keep this declaration outside of the eval-block
my $val = "not defined";

# this with error
eval { $val = $data->{foo}->{bar}; }; 
warn "$@\n" if $@;

# check
say "I'm alive and val is: $val";

# this hopefully without error
eval { $val = $data->{foo}->[0]->{bar}; }; 
warn "$@\n" if $@;

# check again
say "I'm still alive and val is: $val";