How to get the apply method of a case class
Given the case class, I want to get an apply method.
I can do A.apply _
, but there is a way to get it with just A
Example
scala> case class A(s: String)
defined class A
scala> def f[B, C](h: B => C) = h
f: [B, C](h: B => C)B => C
scala> f(A.apply _)
res0: String => A = <function1>
Is it possible to just write f(A)
or something like this
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2 answers
For me in Scala 2.11: works
package sandbox
object ApplyMethod {
import sandbox.OtherApplyTest.C
case class A(s: String)
object B {
def apply(s: String): A = A(s)
}
def D(s: String) = OtherApplyTest.D(s)
def f[T](h: String => T) = h("hello")
def g[T, U](h: T => U) = h
def main(args: Array[String]) {
println(f(A)) // prints A(hello)
// println(f(B)) doesn't compile
println(f(C)) // prints C(hello)
println(f(D)) // prints D(hello)
println(g(A)) // prints A
println(g(C)) // prints C
println(g(D)) // prints <function1>
println(f(g(A))) // prints A(hello)
}
}
object OtherApplyTest {
case class C(s: String)
case class D(s: String)
}
It looks like what you want to do (as well as how you did it) It may not work in the REPL or in an older version of Scala.
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