Illegal declaration of anonymous subroutine at ./utf-2.pl line 8 (#1)
    (F) When using the sub keyword to construct an anonymous subroutine,
    you must always specify a block of code.  See perlsub.

##</code><code>##

#!/usr/local/bin/perl

use strict;
use warnings;
use utf8;
use open qw(:std :utf8);

#sub &#8747; # Integral, vim: insert mode ctrl-k In
#{
#    return 88;
#}

sub &#931;  # Summa, vim: insert mode ctrl-k S*
{
    my $sum;

    $sum += $_ for (@_);

    return $sum;
}

die "Usage: $0 4 3 6...\n" unless @ARGV;
print '&#931;: »', &#931;(@ARGV), "«\n";
#print '&#8747;: »', &#8747;(@ARGV), "«\n";

exit 0;