Clarity and Structure

• isa

• • declares a type
  • • Moose::Util::TypeConstraints
    • • Any, Item, Bool, Undef, Defined, Value, Num, Int, Str, Ref, ScalarRef, ArrayRef, HashRef, CodeRef, RegexpRef, GlobRef, FileHandle, Object and Role
  • types don't need to “exist”
  • • has 'date' => ( isa => “Path::Class” ); # DWIM