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Method names should start with a letter, followed by zero or more
letters, numbers, or underscores.

=head2 Class::MakeMethods::Composite Declaration Syntax

The Composite syntax also provides several ways to optionally
associate a hash of additional parameters with a given method
name. 

=over 4

=item *

I<generator_type> => [ "I<name_1>" => { I<param>=>I<value>... }, ... ]

A hash of parameters to use just for this method name. 

(Note: to prevent confusion with self-contained definition hashes,
described below, parameter hashes following a method name must not
contain the key 'name'.)

=item *

I<generator_type> => [ [ "I<name_1>", "I<name_2>", ... ] => { I<param>=>I<value>... } ]

Each of these method names gets a copy of the same set of parameters.

=item *

I<generator_type> => [ { "name"=>"I<name_1>", I<param>=>I<value>... }, ... ]

By including the reserved parameter C<name>, you create a self
contained declaration with that name and any associated hash values.

=back

Basic declarations, as described above, are treated as having an empty parameter hash.

=cut

package Class::MakeMethods::Composite::Array;

$VERSION = 1.000;
use strict;
use Class::MakeMethods::Composite '-isasubclass';

########################################################################

=head2 Positional Accessors and %FIELDS

Each accessor method is assigned the next available array index at
which to store its value.

The mapping between method names and array positions is stored in
a hash named %FIELDS in the declaring package. When a package
declares its first positional accessor, its %FIELDS are initialized
by searching its inheritance tree.

B<Warning>: Subclassing packages that use positional accessors is
somewhat fragile, since you may end up with two distinct methods assigned to the same position. Specific cases to avoid are:

=over 4

=item *

If you inherit from more than one class with positional accessors,
the positions used by the two sets of methods will overlap.

=item *

If your superclass adds additional positional accessors after you
declare your first, they will overlap yours.

=back

=cut

sub _array_index {
  my $class = shift;
  my $name = shift;
  no strict;
  local $^W = 0;
  if ( ! scalar %{$class . "::FIELDS"} ) {
    my @classes = @{$class . "::ISA"};
    my @fields;
    while ( @classes ) {
      my $superclass = shift @classes;
      if ( scalar %{$superclass . "::FIELDS"} ) {
	push @fields, %{$superclass . "::FIELDS"};
      } else {
	unshift @classes, @{$superclass . "::ISA"}
      }
    }
    %{$class . "::FIELDS"} = @fields
  }
  my $field_hash = \%{$class . "::FIELDS"};
  $field_hash->{$name} or $field_hash->{$name} = scalar keys %$field_hash
}

########################################################################

=head1 METHOD GENERATOR TYPES

=head2 new - Constructor

For each method name passed, returns a subroutine with the following characteristics:

=over 4

=item *

Has a reference to a sample item to copy. This defaults to a reference to an empty array, but you may override this with the C<'defaults' => I<array_ref>> method parameter. 

=item *

If called as a class method, makes a new array containing values from the sample item, and blesses it into that class.

=item *

If called on an array-based instance, makes a copy of it and blesses the copy into the same class as the original instance.