Re^2: Moose composing role with required attribute into existing instance

[tj_thompson]

I think the arguments to with_traits might be wrong though. I had to modify this:

my $point = with_traits( 
   'MyClass', 
   ( 
      'Point',
      'Named'
   ), 
)->new(
   x => 1,
   y => 1,
   name => 'my_point', 
);#To satisfy the required values

To this:

my $point = with_traits( 
   'Point', 
   'Named',
)->new(
   x => 1,
   y => 1,
   name => 'my_point', 
);#To satisfy the required values

The first argument should be the base class you are composing roles into and all remaining arguments should be roles. I wouldn't have bothered correcting this here but maybe it will help someone else. Excellent solution.

[jandrew]

You are correct the syntax for the code you posted needs the class followed by roles. I initially misread Point as a Role. I tend to put all of the appended roles in a list form though just to improve readability (even if there is just one). Also if you don't like the method call on a method result you can separate them into two and the required=>1, elements of the attributes still won't error.

my $named_point_class = with_traits( 
   'Point',
   (
    'Named',
   ),
);
my $point_instance = $named_point_class->new(
   x => 1,
   y => 1,
   name => 'my_point', 
);

Update:If you are using this in boilerplate the role can be a dummy name as well and it still works!