Question 1

How do I use keyword arguments with attr_extras?

Accepted Answer

Use array notation like attr_initialize [:bar, :baz!] for optional and required keywords. Required keywords raise KeyError if missing, and unknown keywords trigger ArgumentError, as explained in the usage section.

Question 2

attr_extras vs Struct in Ruby: which is better?

Accepted Answer

attr_extras avoids Struct's pitfalls like overuse of inheritance and offers more control with explicit initializers. Struct is simpler for data holders, but attr_extras is superior for behavior-focused classes, per the linked article on Struct downsides.

Question 3

How to prevent attr_extras methods from affecting all classes?

Accepted Answer

Switch to explicit mode by requiring 'attr_extras/explicit' and extending AttrExtras.mixin in each class. This is essential for libraries to avoid namespace pollution, as noted in the explicit mode documentation.

Question 4

What's the difference between pattr_initialize and vattr_initialize?

Accepted Answer

pattr_initialize defines private readers with the initializer, ideal for internal use. vattr_initialize adds public readers and value object equality, making objects immutable and comparable, useful for domain models.

Question 5

How do I handle dynamic default values with attr_initialize?

Accepted Answer

Default values are evaluated at class load time, so for dynamic defaults, use a regular Ruby method or a block in the initializer. The README suggests workarounds like defining a private method to compute values on demand.

Question 6

Can I use attr_extras with Rails Active Record?

Accepted Answer

Yes, attr_extras complements Rails well; for instance, attr_id_query is designed for Active Record IDs. However, be mindful of global method addition in Rails apps to prevent conflicts with other gems.

AttrExtras

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