#!/usr/bin/perl -w

sub polymorphic {

  my $context=wantarray();

  if ($context) {
    print "list context\n";
    return @_;
  } elsif (defined($context)) {
    print "scalar context\n";
    return join ":", @_;
  } else {
    warn "value of polymorphic() used in void context. Values were (\n";
    # so no point in returning anything, but do print
    print join ",", @_;
    print ")\n";
  }
}

sub show_args {
  print "got ", scalar(@_), " args:\n";
  map {print "  $_\n" } @_;
}

show_args("a", polymorphic("b","c","d"));

my $string=polymorphic(1,2,3);
my @array=polymorphic(4,5,6);

show_args($string,@array);

# make warning 1

polymorphic("unused");

# following is tricky because we don't know context until tricky is
# actually called.
sub tricky {
  polymorphic(@_);
}

my $string2=tricky(qw(a b c d));
my @array2=tricky(qw(s t u v));

show_args($string2,@array2);
# make warning 2
tricky(qw(fee fi fo fum));

# what happens if we use return keyword explicitly?
sub tricky_2 {
  return polymorphic(@_);
}

my $string3=tricky_2(qw(a e i o u));
my @array3=tricky_2(qw(w x y z));

show_args($string3,@array3);

# (turns out we can use return or not; same result--no warning)
# (but this should generate one)
tricky_2(5,6,7,8);

sub tricky_3 {
  my $first=shift;
  my $second=shift;
  my @remaining=@_;

  print "$first, $second, (";
  print join ",", @remaining;
  print ")\n";

};