In reply to Michael54:
The field macros are used to generate the transaction methods in the above referenced cookbook article. Using the field macros removes the requirement for the user to code their own methods. However due to the code inefficiency and inability to handle all data types, we recommend users not use the field macros and code their own methods.
The field macros can also be used for uvm_components, but since components aren’t cloned/copied/compared/recorded/etc. like transactions are, there should be no reason to use any field macros.