Revert "clarification re the limitations of the "map" array delegation handler"

[gitmo/Moose.git] / lib / Moose / Meta / Attribute / Native / Trait / Array.pm

package Moose::Meta::Attribute::Native::Trait::Array;
use Moose::Role;

our $VERSION   = '1.9900';
$VERSION = eval $VERSION;
our $AUTHORITY = 'cpan:STEVAN';

with 'Moose::Meta::Attribute::Native::Trait';

sub _helper_type { 'ArrayRef' }

no Moose::Role;

1;

__END__

=pod

=head1 NAME

Moose::Meta::Attribute::Native::Trait::Array - Helper trait for array delegation

=head1 SYNOPSIS

    package Stuff;
    use Moose;

    has 'options' => (
        traits  => ['Array'],
        is      => 'ro',
        isa     => 'ArrayRef[Str]',
        default => sub { [] },
        handles => {
            all_options    => 'elements',
            add_option     => 'push',
            map_options    => 'map',
            filter_options => 'grep',
            find_option    => 'first',
            get_option     => 'get',
            join_options   => 'join',
            count_options  => 'count',
            has_options    => 'count',
            has_no_options => 'is_empty',
            sorted_options => 'sort',
        },
    );

    no Moose;
    1;

=head1 DESCRIPTION

This trait provides native delegation methods for array references.

=head1 DEFAULT TYPE

If you don't provide an C<isa> value for your attribute, it will default to
C<ArrayRef>.

=head1 PROVIDED METHODS

=over 4

=item * B<count>

Returns the number of elements in the array.

  $stuff = Stuff->new;
  $stuff->options( [ "foo", "bar", "baz", "boo" ] );

  print $stuff->count_options; # prints 4

This method does not accept any arguments.

=item * B<is_empty>

Returns a boolean value that is true when the array has no elements.

  $stuff->has_no_options ? die "No options!\n" : print "Good boy.\n";

This method does not accept any arguments.

=item * B<elements>

Returns all of the elements of the array as an array (not an array reference).

  my @option = $stuff->all_options;
  print "@options\n";    # prints "foo bar baz boo"

This method does not accept any arguments.

=item * B<get($index)>

Returns an element of the array by its index. You can also use negative index
numbers, just as with Perl's core array handling.

  my $option = $stuff->get_option(1);
  print "$option\n";    # prints "bar"

If the specified element does not exist, this will return C<undef>.

This method does accepts just one argument.

=item * B<pop>

Just like Perl's builtin C<pop>.

This method does not accept any arguments.

=item * B<push($value1, $value2, value3 ...)>

Just like Perl's builtin C<push>. Returns the number of elements in the new
array.

This method accepts any number of arguments.

=item * B<shift>

Just like Perl's builtin C<shift>.

This method does not accept any arguments.

=item * B<unshift($value1, $value2, value3 ...)>

Just like Perl's builtin C<unshift>. Returns the number of elements in the new
array.

This method accepts any number of arguments.

=item * B<splice($offset, $length, @values)>

Just like Perl's builtin C<splice>. In scalar context, this returns the last
element removed, or C<undef> if no elements were removed. In list context,
this returns all the elements removed from the array.

This method requires at least one argument.

=item * B<first( sub { ... } )>

This method returns the first item matching item in the array, just like
L<List::Util>'s C<first> function. The matching is done with a subroutine
reference you pass to this method. The subroutine will be called against each
element in the array until one matches or all elements have been checked.

  my $found = $stuff->find_option( sub {/^b/} );
  print "$found\n";    # prints "bar"

This method requires a single argument.

=item * B<grep( sub { ... } )>

This method returns every element matching a given criteria, just like Perl's
core C<grep> function. This method requires a subroutine which implements the
matching logic.

  my @found = $stuff->filter_options( sub {/^b/} );
  print "@found\n";    # prints "bar baz boo"

This method requires a single argument.

=item * B<map( sub { ... } )>

This method transforms every element in the array and returns a new array,
just like Perl's core C<map> function. This method requires a subroutine which
implements the transformation.

  my @mod_options = $stuff->map_options( sub { $_ . "-tag" } );
  print "@mod_options\n";    # prints "foo-tag bar-tag baz-tag boo-tag"

This method requires a single argument.

=item * B<reduce( sub { ... } )>

This method turns an array into a single value, by passing a function the
value so far and the next value in the array, just like L<List::Util>'s
C<reduce> function. The reducing is done with a subroutine reference you pass
to this method.

  my $found = $stuff->reduce_options( sub { $_[0] . $_[1] } );
  print "$found\n";    # prints "foobarbazboo"

This method requires a single argument.

=item * B<sort>

=item * B<sort( sub { ... } )>

Returns the elements of the array in sorted order.

You can provide an optional subroutine reference to sort with (as you can with
Perl's core C<sort> function). However, instead of using C<$a> and C<$b> in
this subroutine, you will need to use C<$_[0]> and C<$_[1]>.

  # ascending ASCIIbetical
  my @sorted = $stuff->sort_options();

  # Descending alphabetical order
  my @sorted_options = $stuff->sort_options( sub { lc $_[1] cmp lc $_[0] } );
  print "@sorted_options\n";    # prints "foo boo baz bar"

This method accepts a single argument.

=item * B<sort_in_place>

=item * B<sort_in_place( sub { ... } )>

Sorts the array I<in place>, modifying the value of the attribute.

You can provide an optional subroutine reference to sort with (as you can with
Perl's core C<sort> function). However, instead of using C<$a> and C<$b>, you
will need to use C<$_[0]> and C<$_[1]> instead.

This method does not define a return value.

This method accepts a single argument.

=item * B<shuffle>

Returns the elements of the array in random order, like C<shuffle> from
L<List::Util>.

This method does not accept any arguments.

=item * B<uniq>

Returns the array with all duplicate elements removed, like C<uniq> from
L<List::MoreUtils>.

This method does not accept any arguments.

=item * B<join($str)>

Joins every element of the array using the separator given as argument, just
like Perl's core C<join> function.

  my $joined = $stuff->join_options(':');
  print "$joined\n";    # prints "foo:bar:baz:boo"

This method requires a single argument.

=item * B<set($index, $value)>

Given an index and a value, sets the specified array element's value.

This method returns the value at C<$index> after the set.

This method requires two arguments.

=item * B<delete($index)>

Removes the element at the given index from the array.

This method returns the deleted value. Note that if no value exists, it will
return C<undef>.

This method requires one argument.

=item * B<insert($index, $value)>

Inserts a new element into the array at the given index.

This method returns the new value at C<$index>.

This method requires two arguments.

=item * B<clear>

Empties the entire array, like C<@array = ()>.

This method does not define a return value.

This method does not accept any arguments.

=item * B<accessor($index)>

=item * B<accessor($index, $value)>

This method provides a get/set accessor for the array, based on array indexes.
If passed one argument, it returns the value at the specified index.  If
passed two arguments, it sets the value of the specified index.

When called as a setter, this method returns the new value at C<$index>.

This method accepts one or two arguments.

=item * B<natatime($n)>

=item * B<natatime($n, $code)>

This method returns an iterator which, on each call, returns C<$n> more items
from the array, in order, like C<natatime> from L<List::MoreUtils>. A coderef
can optionally be provided; it will be called on each group of C<$n> elements
in the array.

This method accepts one or two arguments.

=back

=head1 BUGS

See L<Moose/BUGS> for details on reporting bugs.

=head1 AUTHOR

Stevan Little E<lt>stevan@iinteractive.comE<gt>

=head1 COPYRIGHT AND LICENSE

Copyright 2007-2010 by Infinity Interactive, Inc.

L<http://www.iinteractive.com>

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.

=cut