Почему не работает?

#!/usr/bin/env perl

use strict;
use warnings;
use Data::Dumper;

my $hash = {
    key1   => 'value1',
    key2   => 'value2',
    key3   => 'value3',
};

my @options = map { "--$_" => $hash->{$_} } # line 13
              grep { defined $hash->{$_} }  # line 14
              qw(key1 key4);                # line 15

print Dumper(\@options);

syntax error at ./test.pl line 14, near "grep"
Global symbol "@options" requires explicit package name (did you forget to declare "my @options"?) at ./test.pl line 17.
Execution of ./test.pl aborted due to compilation errors.

Not enough arguments for map at ./test.pl line 14, near "grep"
syntax error at ./test.pl line 14, near "grep"
Execution of ./test.pl aborted due to compilation errors.

-my @options = map { "--$_" => $hash->{$_} } # line 13
+my @options = map { ("--$_") => $hash->{$_} } # line 13