$self->foo();
foo($self);

##</code><code>##

package A;

sub new { bless {}, shift }
sub foo { 'A' }

sub bar {
   my $self = shift;

   print '$self->foo() = ', $self->foo(), "\n";
   print 'foo( $self ) = ', foo( $self ), "\n";
}

package B;

our @ISA = ('A');
sub foo { 'B' }

package main;

my $obj_a = A->new();
my $obj_b = B->new();

print "object A call to bar():\n";
$obj_a->bar();
print "object B call to bar():\n";
$obj_b->bar();
__END__
object A call to bar():
$self->foo() = A
foo( $self ) = A
object B call to bar():
$self->foo() = B
foo( $self ) = A

##</code><code>##

($x) = foo();
 $x  = foo();

##</code><code>##

my @foo_subs = ( 'sub { return ( 4, 5, 6 ) }',
                 'sub { my @x = ( 4, 5, 6 ); return @x; }',
                 'sub { wantarray ? ( 7 ) : 8 }',
               );
foreach my $foo_str ( @foo_subs ) {
    my $foo = eval $foo_str;

    my ($x) = $foo->();
    my  $y  = $foo->();

    print "foo = $foo_str\n";
    print "(\$x) = $x\n";
    print " \$y  = $y\n";
}
__END__
foo = sub { return ( 4, 5, 6 ) }
($x) = 4
 $y  = 6
foo = sub { my @x = ( 4, 5, 6 ); return @x; }
($x) = 4
 $y  = 3
foo = sub { wantarray ? ( 7 ) : 8 }
($x) = 7
 $y  = 8

##</code><code>##

for ( @x ) { foo( $_ ) }
map { foo( $_ ) } @x;

##</code><code>##

sub foo {
    my $wa = wantarray;
    if    ( $wa )         { print "array\n"  }
    elsif ( defined $wa ) { print "scalar\n" }
    else                  { print "void\n"   }
}

my @x = ( 1, 2 );

print "for(\@x){foo()}:\n";
for ( @x ) { foo( $_ ) }      # void
print "map{foo()} \@x:\n";
map { foo( $_ ) } @x;         # array
__END__
for(@x){foo()}:
void
void
map{foo()} @x:
array
array

##</code><code>##

sub baz { return 11 unless shift }

print 'baz(5): ', baz(5), "\n";
print 'baz(0): ', baz(0), "\n";

##</code><code>##

baz(5): 5
baz(0): 11

##</code><code>##

my $FOO = 'foo';
sub bar { $_[0] = 'bar' }

print $FOO, "\n";
print bar( $FOO ), "\n";
print $FOO, "\n"; 

##</code><code>##

foo
bar
bar

##</code><code>##

for my $s ( qw( a b c ) ) { $s =~ s/$/\n/ && print $s }

##</code><code>##

Modification of a read-only value attempted at interview.pl line