Scala 12.x and Java 11 `String.lines`, how to force the implicit conversion in a chained call?

Question

Problem description Scala StringOps provides a lines method that returns an Iterator[String]. Java 11 added lines() with return type java.Stream[String].

In a chained method call like

val text: String
text.lines.foldLeft("")(_ + _)

the code will no longer compile and throw an exeption that foldLeft is not defined on java.Stream[String]. As far as I understand the implicit resolution is no longer applied as the lines method now is already found in java.String.

How can I express that I want the implicit to be applied (the one without parens) isntead of the java.String.lines()

Additional info

I found linesIterator but it is deprecated.
Downgrading is an option but is there a way around it.
val text : StringOps looks realy ugly but solved it but I am unhappy with this solution

Also, I think you can do `(text: StringOps).lines.foldLeft(...)` — Clashsoft, Oct 15 '18 at 11:29
Nice catch, thx :) `(text: StringOps)` with the parents doesn't braek the chain. — Andreas Neumann, Oct 15 '18 at 11:32

score 18 · Accepted Answer · answered Oct 15 '18 at 11:31

18

The conflict between StringOps#lines and jdk11 java.lang.String#lines is a bug in scala, see issue 11125.

The fix for this bug is to un-deprecate linesIterator, which was done in 2.12.7.

Welcome to Scala 2.12.7 (OpenJDK 64-Bit Server VM, Java 11).

scala> "a".lines
res0: java.util.stream.Stream[String] = java.util.stream.ReferencePipeline$Head@2df259d0

scala> "a".linesIterator
res1: Iterator[String] = <iterator>

answered Oct 15 '18 at 11:31

obourgain

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1

The intermediate solution then is to use `Predef.augmentString(` until this is fixed in 2.13 ? – Andreas Neumann Oct 15 '18 at 11:35
3

Yes, `Predef.augmentString("")` seems to be the less ugly solution for now. – obourgain Oct 15 '18 at 11:40
I wish I could give you more upvotes. – Thiago Mata Oct 06 '22 at 08:07

score 5 · Answer 2 · answered Oct 15 '18 at 11:34

5

You can force Scala to use the implicit conversion to StringOps, which will use the old lines method:

(text: StringOps).lines.foldLeft("")(_ + _)

answered Oct 15 '18 at 11:34

Clashsoft

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This and inserting `augmentString` are equivalent, can't think of a strong reason to prefer one or the other. ( But note that `StringOps` is in `scala.collection.immutable` and isn't imported by default.) – Seth Tisue Oct 16 '18 at 22:00

Scala 12.x and Java 11 `String.lines`, how to force the implicit conversion in a chained call?

2 Answers2