CODEWITHSUNDEEP
scala
stella
stella

Reputation: 2596

Package name lookup rules in scala

I came out to scala programmin from Java so it's not clear to me how we should use relative imports in Scala and what is the exact name lookup rules? Suppose I have the following:

pack.age
   |
   |----MyClass.scala

com.age
   |
   |---AnotherClass.scala

I need to import MyClass.scala into AnotherClass.scala. Since Scala supports only relative imports I wrote the following:

import _root_.pack.age.MyClass

and it worked fine. But when I tried to delete _root_ from there, there was no compile time error either.

import pack.age.MyClass

works fine as well.

So, what is the package name lookup rules in Scala?

Upvotes: 2

Views: 172

Answers (2)

Zernike
Zernike

Reputation: 1766

All imports are relative, so sometimes collisions can appear. For example, if you have package com.org.project.scala then next import scala._ looks up for system package too. _root_ is implicit top package that can be utilised for simulation of absolute path.

Upvotes: 3

Ren
Ren

Reputation: 3455

I believe there is an order of operations here. If you had package.age.MyClass within com.age (ie. com.age.package.age.MyClass), as well as package.age.MyClass, the former would be picked up. If you wanted the latter, you would need to use the root syntax.

As there is only one place this class can be picked up from (in root), that is the package picked up.

Upvotes: 3

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