How to map method name X to method name Y in Scala like in List

Question

Referring to the answer of the following question:

List.empty vs. List() vs. new List()

How did the developers of Scala map the method apply[A](xs: A*) defined in the List object , to be usable as List[A](cs: A*) ?

Also how did they translate aListInstance(n: Int) to the method apply(n: Int) (which returns the n'th element of the list) defined in the List class ?

In both cases I'm calling the apply() methods without writing .apply() in my code. How does that work?

Answer 1

It works because the Scala Language Specification says so.

foo(bar)

is translated to

foo.apply(bar)

just like

foo.bar = baz

is translated to

foo.bar_=(baz)

and

foo(bar) = baz

is translated to

foo.update(bar, baz)

and

foo bar baz

is translated to

foo.bar(baz)

and

foo bar_: baz

is translated to

baz.bar_:(foo)

and so on and so forth.