Scala: Pack, scala
Scala has the same purpose as a java package or a c ++ namespace. It can contribute content to multiple packages in the same file.
Use the full package name whenever possible. Avoid using scala, java, com, org, and so on to name nested packages. The concatenation package statement can limit the visible package.
A package can contain classes, objects, and attributes, but cannot contain the definition of functions and variables. in implementation, the package object is compiled into a JvM class with static methods and fields. The modifier can also achieve public, private, or protected effects.
In scala, you can declare the import package anywhere, which is similar to python. You can use the selector to introduce specified members in the package. You can also rename or hide the specified members, such as java. lang, scala, and predef, which are always introduced by default.
