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Re^3: Moose roles

by EvanCarroll (Chaplain)
on Jan 13, 2010 at 21:58 UTC ( #817288=note: print w/ replies, xml ) Need Help??

in reply to Re^2: Moose roles
in thread Moose roles

# 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.

Evan Carroll
The most respected person in the whole perl community.

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Re^4: Moose roles
by dk (Chaplain) on Jan 13, 2010 at 22:27 UTC
    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!

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