A programmers quick guide to Perl 5 references
(presuming prior knowledges of pointers/references
 in some language, such as C)



  $a_L = \@a;		# Reference to a list
  $a_H = \%a;		# Reference to a hash

  # This is useful because these are now scalars, so we can easily
  # pass them in the parameter list and the return list

  foreach $i ( @$a_L ) ..	# The list of the list ref

  foreach $k ( keys %$a_H ) ..	# The hash of the hash ref

  $a_L->[1]		# Element one of the list referred to by $a_L
  $$a_L[1]		# Another way to do it - I like the -> construct better

  $a_H->{field}		# Same for hashes

  $#$a_L		# The size of the list referenced by $a_L

  # Let's say you want an array of hashes
			# This bit is nothing new
  $tmp_H = $a_L->[0]	# Element 0 - is a hash ref
  $tmp_H->{field}	# Reference field of the hash

			# A quicker way to do it:
  $a_L->[0]->{field}	# Referencing 'field' of hash 0

  $a_L->[0]{field}	# Shorter typing.  You only need the first '->'
  $a[0]{field}		# This is different - we use @a, not a ref to a list

  # We can get more complex:
  $a_L->[0]->{field}->[3]	# 0th element of list ref'd by $a_L is a
				# hash that we take 'field' from which is
				# a list which we get element 3 of

  # Or even more complex:
  $a_L->[0]->{$keys_L->[$a[3]]}->[3]

  # To deal with ambiguity, you can use {} to force the 'order' of dereferencing
  @{$a_L->[0]}		# We want the array ref'd by the 0th element of the
			# array ref'd by $a_L

# See 'man perldsc' for much more information, especially on making
# sure that you are properly allocating space for your new creations
# For example, you have to be careful doing stuff like:
  $a_L = \(1, 2, 3);

# You probably want to do:
  $a_L = [1, 2, 3];		# Makes a reference to an array it creates