Is there a good way of making all the object attributes readonly in Moo? Something that would allow me to replace:

package Foo {
    use Moo;
    has 'attr_A' => ( is => 'ro', default => sub { 'A' } );
    has 'attr_B' => ( is => 'ro', default => sub { 'B' } );
    has 'attr_C' => ( is => 'ro', isa => sub { die unless $_[0] > 0 } 
+);
}
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With something like:

package Foo {
    use Moo;

    # this is where the magic happens

    has 'attr_A' => ( default => sub { 'A' } );
    has 'attr_B' => ( default => sub { 'B' } );
    has 'attr_C' => ( isa => sub { die unless $_[0] > 0 } );
}
[download]

There is an interesting blog post by mascip, about the possibility of enabling immutability for all the objects of a given class. The post refers to Moose, and its author seems to ask about a stronger restriction - making the object truly immutable. I'm only looking for some way to make the  is => 'ro' a default for all the attributes of a given class. Still, I wanted to link this post here since it provides a good explanation for the reasoning behind my question.

One 'bad way' I can think of would be using Filter::Simple, but I hope to find another way to do it. Humbly seeking your advice.