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

my $i=0;
my %hARGV = map {
  if (/^--(\w+)=(\w+)$/) {

    # option => value
    $1 => $2;

  } elsif (/^--(\w+)$/) {

    # flag => 1
    $1 => 1

  } elsif (m{^[\w/]}) {

    # filename => fileorder
    $_ => $i++;

  } else {

    # bad argument - add nothing to the result hash
    warn "Invalid option: <$_> - options must begin with "
      ."-- or be a legal file name";
    ();

  }
} @ARGV;
print Dumper(\%hARGV);