$ cat monktest.pl 
#!/usr/bin/perl

use strict;
use warnings;

use Data::Dumper;

my @foo = ( qw/this is the sample line/ );
my @bar = ( 1,2,4 );
print Dumper(\@foo);

my $barstr = join(',',@bar);
print "barstr: $barstr\n";

my @line = @foo[@bar];
print "@line\n";;

my @line2 = @foo[ eval $barstr ];
print "@line2\n";

exit;

__END__
$ ./monktest.pl 
Scalar value @foo[ eval $barstr ] better written as $foo[ eval $barstr ] at ./monktest.pl line 18.
$VAR1 = [
          'this',
          'is',
          'the',
          'sample',
          'line'
        ];
barstr: 1,2,4
is the line
is the line