Migration tool to switch from the current collections to the strawman

[julienrf]

Migration tool to switch from the current collections to the strawman

[julienrf]

I’m sorry the issue description lacks details. Let me add some details: to move a code base to the strawman, a rule of thumb is just to import collection types from the strawman.collection namespace instead of scala.collection. However, there are some corner cases:

• some aliases are in the scala or scala.Predef namespaces, which are (in general) automatically imported by Scala projects ;
• implicit conversions enriching Arrays and providing Range syntax are in scala.Predef too. I think that we will have to unimport the implicits that are in Predef and to import those that are (currently) in strawman.collection.

[julienrf]

Corner case: 1 to 10 should produce a strawman.collection.immutable.Range. (We will have a similar problem with Array and String operations)

[ShaneDelmore]

What exactly is the issue? I think scalafix can handle this fairly easily but am not sure I am understanding what the problem is.

[olafurpg]

Can you provide some example diffs @julienrf ? It should be possible to implement some of these with Scalafix.

[julienrf]

• When a “default” collection is used (e.g. List) we should unimport it from the scala package and import it from strawman.collection:

+ import scala.{List => _}
+ import strawman.collection.immutable.List
List(1, 2, 3)

+ import scala.{Nil => _}
+ import strawman.collection.immutable.Nil
1 :: 2 :: 3 :: Nil

• When a collection whose type is not aliased in the scala package is used, we should replace its import with one that points to strawman.collection:

- import scala.collection.mutable.ArrayBuffer
+ import strawman.collection.mutable.ArrayBuffer

• When the Range syntax is used we should replace it with the one from the strawman:

+ import scala.Predef.{intWrapper => _}
+ import strawman.collection.intWrapper
1 to 10

(maybe it is enough to just import the new implicit conversion. I don’t know if there will be an ambiguity if don’t unimport the one in Predef)

• When collection operations are used with String and Array values, we should replace the decorators with the one from the strawman:

+ import scala.Predef.{augmentString => _}
+ import strawman.collection.stringToStringOps
"foo" ++ "bar"

+ import scala.Predef.{intArrayOps => _}
+ import strawman.collection.arrayToArrayOps
Array(1, 2, 3) map (_ + 1)