When Ruby programmers say that some class “quacks like an…
““When Ruby programmers say that some class “quacks like an Array,” they usually mean that it’s not necessarily an Array nor a descendant of Array, but it responds to most of the same methods as Array and can therefore be used wherever an Array would be used.””
About This Quote
This interpretation was drafted with AI assistance. It is one reading of the quote, not the author's own explanation.
A class can be used like an Array if it implements the same methods, even without inheriting from Array.
In simple terms: Non‑Array class can act like an Array by matching its interface.
Design objects to match required interfaces.
Themes
Mood
Type
When to use this quote
- API design
- library usage
- code reuse
- testing
- refactoring
Key Concepts
Questions to Reflect On
- What methods must your class implement to be interchangeable?
- How does duck typing affect code safety?
If the class lacks subtle Array behaviors, substitution may fail.