A first-class object is a value or language entity that can be represented, stored, passed, and manipulated like other values. Data-oriented programming applies this idea to data and fields, using generic collections and functions instead of requiring concrete types. section 15.3 section 10.5
The practical payoff is reproducibility: capture a function’s data arguments, copy them into a console, and improve or test behavior without triggering the original endpoint. section 15.3
Reproducing a book search
Capture catalogData and query from Catalog.searchBooksByTitle, recreate the call in a REPL, then test 'Habit'. The captured catalog data remains ordinary data that can be inspected and reused while the search implementation changes.
