menu_book Course Curriculum (Kotlin) expand_more
Scope function apply
Learn scope function apply in Kotlin through a focused explanation, a dedicated topic-specific example, an engineering boundary, and a mastery check.
scope function apply is an atomic Kotlin topic inside Extensions and DSLs. The example uses the named construct directly so you can see its syntax, data flow, and observable behavior.
Read the code by locating the exact feature named scope function apply, then trace the value before and after that feature runs. This lesson is intentionally isolated from neighboring topics: changing identifiers alone would not reproduce the same behavior because the construct itself is different.
Topic-specific example
data class User(var name:String="",var age:Int=0)
fun main(){println(User().apply{name="A";age=20})}For scope function apply, test the boundary that makes the feature meaningful: invalid input, an empty value, a missing branch, lifecycle/cleanup, or a type/runtime constraint. Do not infer correctness only from the happy path.