Re^3: Moose roles

[EvanCarroll]

 # Done with `auto_deref => 1`
 @list = $obj-> prop;

 # Done with a custom writer attribute that takes an array, and stores
+ a reference to it.
 # internally Moose uses a plain perl hash (most complex datastructure
+ in perl), this 
 # limits it to not having true non-array properties (but a scalar arr
+ay-ref works)
 $obj->prop(@list);

 # assuming you mean $arrayRef
 # Here the getter would have to call wantarray() which is exactly wha
+t auto_deref => 1
 # will set up for you.
 $array = $obj->prop;

 # assuming you mean $arrayRef, this already works so long as the type
+ is ArrayRef
 # or, a parent thereof.
 $obj->prop($array);

All you need is a custom attribute setter that takes a list and converts it to an array ref. Because n-parameterized types are not supported (you can't have a type of intStr of type (Int, Str), coercing on a custom type is out the question. (unless your doing something scarry). This leaves a custom writter that does something like.

sub foo_writer {
 if ( length @_ > 1 ) {
  \@_
 }
 else {
  die 'invalid arg' unless ref $_[0] eq 'ARRAY';
  $_[0];
 }
}

read the docs on has() writer argument. this is also pseudo code, my writer returns the value, I believe you'd have to explicitly set it though.

[dk]

Thanks Evan, that's more or less what I figured out, I just used "around" instead of combination of "writer" and "auto_deref".

Actually, I found a completely another way to approach the problem. I've uploaded a proof of concept to CPAN, when it will be available I'll update the top post.

Thanks again!