NAME

SYNOPSIS

   package Stuff;

   use Moose;
   use MooseX::Lists;

   has_list a => ( is => 'rw', isa => 'ArrayRef');
   has_list h => ( is => 'rw', isa => 'HashRef' );

   has_list same_as_a => ( is => 'rw' );

   ...

   my $s = Stuff-> new(
        a => [1,2,3],
        h => { a => 1, b => 2 }
   );

   has_list a => ( is => 'rw', isa => 'ArrayRef');
   has_list h => ( is => 'rw', isa => 'HashRef' );

   ...

   my @list   = $s-> a;     # ( 1 2 3 )
   my $scalar = $s-> a;     # [ 1 2 3 ]

   $s-> a(1,2,3);           # 1 2 3
   $s-> a([1,2,3]);         # 1 2 3
   $s-> a([]);              # empty array
   $s-> a([[]]);            # []

   my %list = $s-> h;       # ( a => 1, b => 2 )
   my $sc   = $s-> h;       # { a => 1, b => 2 }

   $s-> h(1,2,3,4);         # 1 2 3 4
   $s-> h({1,2,3,4});       # 1 2 3 4
   $s-> h({});              # empty hash

   has_list a => ( 
        is  => 'rw', 
        isa => 'ArrayRef',
        writer  => 'wa',
        clearer => 'ca',
        );
   has_list h => ( 
        is  => 'rw', 
        isa => 'HashRef',
        writer  => 'wh',
        clearer => 'ch',
        );

    ...

   # reading part is identical to the above

   $s-> wa(1,2,3);          # 1 2 3
   $s-> wa([1,2,3]);        # [1 2 3]
   $s-> wa();               # empty array
   $s-> ca();               # empty array
   $s-> wa([]);             # []

   $s-> wh(1,2,3,4);        # 1 2 3 4
   $s-> wh({1,2,3,4});      # error, odd number of elements
   $s-> wh();               # empty hash
   $s-> ch();               # empty hash

DESCRIPTION

The problem this module tries to solve is to provide an acceptable API for setting and accessing array and hash properties in list context. The problem in implementing such interface is when a handler accepts both arrays and arrayrefs, how to set an empty array, and differentiate between a set-call with an empty list or a get-call. Depending on the way a method is declared, two different setting modes are proposed.

The first method, when "writer" is not explictly set (default), tries to deduce if it needs to dereference the arguments. It does so by checking if the argument is an arrayref. This means that the only way to clear an array or hash it to call it with "[]" or "{}", respectively.

The second method is turned on if "writer" was explicitly specified, which means that if it is called with no arguments, this means an empty list. This method never dereferences array- and hashrefs.

METHODS

has_list

Replacement for "has", with exactly same syntax, expect for "isa", which must begin either with "ArrayRef" or "HashRef". If "isa" is omitted, array is assumed.

When a method is declared with "has_list", internally it is a normal perl array or hash. The method behaves differently if called in scalar or list context. See below for details.

ArrayRef

In get-mode, behaves like "auto_deref": in scalar context, returns direct reference to the array; in the list context, returns defererenced array.

In set-mode without "writer" specified, behaves asymmetrically: if passed one argument, and this argument is an arrayref, treats it as an arrayref, otherwise dereferences the arguments and creates a new arrayref, which is stored internally. I.e. the only way to clear the array is to call "->method([])".

In set-mode with "writer" specified always treats input as a list.

HashRef

In get-mode, behaves like "auto_deref": in scalar context, returns direct reference to the hash; in the list context, returns defereenced hash.

In set-mode without "writer" specified behaves asymmetrically: if passed one argument, and this argument is a hashref, treats it as a hashref, otherwise dereferences the arguments and creates a new hashref, which is stored internally. I.e. the only way to clear the hash is to call "->method({})".

In set-mode with "writer" specified always treats input as a list.

AUTHOR

THANKS