What you need to bear in mind, is that an attribute could have several different names associated with it. Consider:

use v5.14;

package Foo {
   use Moo;
   has foo1 => (
      is       => "rw",
      init_arg => "foo2",
      reader   => "foo3",
      writer   => "foo4",
   );
}

# Create an object, setting the attribute...
my $obj = Foo->new(foo2 => 40);

# Increment the value...
$obj->foo4( $obj->foo3 + 1 );

# Or cheat and access the hashref directly...
$obj->{foo1}++;

# Print the value of the attribute...
say $obj->foo3;

[download]

Moo does have all this data buried away, but you may be better off using Moose or Mouse which provide documented, public APIs for all this attribute introspection stuff.

package Cow { use Moo; has name => (is => 'lazy', default => sub { 'Mooington' }) } say Cow->new->name

In reply to Re^3: Enumerating all attributes of a Moo object by tobyink
in thread Enumerating all attributes of a Moo object by McA

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