Seth Tisue SethTisue

here is my 2021 foreword to Dean Wampler’s Scala 3 book for O’Reilly

“Scala [...] is worth fighting for.” ✊

From `scala.xml.pull` to `javax.xml.stream.events`

Want to process XML that's too large to fit in memory?

The Scala standard library used to offer scala.xml.pull for this. It became part of the scala-xml library when scala-xml became separate. But then scala.xml.pull got deprecated (in scala.xml 1.1.1) and finally removed entirely (in scala-xml 2.0.0-M1). The recommended replacement is javax.xml.stream.events.

I had some old code that used scala.xml.pull to digest my iTunes Music Library.xml and print various statistics. Recently I converted it to Scala 3, so I decided to get off the deprecated API at the same time.

So, here is the before-and-after. Perhaps this will help other users of scala.xml.pull who want to convert.

The draft that was here has been published at: https://github.com/scala/scala/releases/tag/v2.13.3

If you notice anything in the notes that could be improved, you can still comment on this gist and I'll see it and respond.

Collections fixes

Fix 2.12-only bug where some toX methods could expose the underlying mutability of a ListBuffer-generated collection (#8674)

(The release includes other collections bugfixes, but this one is especially notable.)

Java interoperability

Highlights

The main purpose of this release is to fix the following regressions in 2.12.9:

Fix regression in large string interpolations with non-String typed splices (#8315)
Revert "Generate shallower ASTs in pattern translation" (#8327, reverting #8061)
Fix regression in classpath when JARs have 'a.b' entries beside 'a/b' (#8321)

Further highlights

Fixes with compatibility implications

Scala 2.12.9 generates shallower ASTs in pattern translation, to reduce stack size requirements (-Xss) during compilation.

Scala.js users must update to 0.6.28+ or 1.0.0-M8+ for compatibility with Scala 2.12.9. (#7375)

Highlights of 2.12.9

Improved compatibility with JDK 11, 12, and 13 (see below)

in Scala 2, they don't chain 😇, even if we try to give the compiler an assist

can we make them chain in Dotty? 😈

let's try it!

first let's set up sbt:

% cat project/plugins.sbt

these notes have moved to https://github.com/scala/scala/releases/tag/v2.13.0-RC2

The notes

the notes are now published at https://github.com/scala/scala/releases/tag/v2.13.0-RC1

Feedback?

it's not too late to improve the notes!

please send comments any of the following ways:

	public <T> boolean exists(scala.collection.Iterable<T>, scala.Function1<T, java.lang.Object>);
	Code:
	0: new #19 // class scala/util/boundary$Label
	3: dup
	4: invokespecial #44 // Method scala/util/boundary$Label."<init>":()V
	7: astore_3
	8: aload_1
	9: aload_0
	10: aload_2
	11: aload_3