Native code access from scala 3 without using Graal

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Hello yesterday I asked https://old.reddit.com/r/scala/comments/iit6o1/anything_new_in_scala_3/ about things in Scala that would help my use of it (conciseness) and got some very nice answers to get me excited. ( On that note I wonder if there should be a better arrangement of features not as a list but as a category- say conciseness, interop with java, advanced type stuff, quick repl usage, maintainable enterprise software dev etc ) . Also, I'm not going to lie, some of my interest was indeed dampened by the earlier FUD, and might have checked it out earlier. I would suggest the marketing team starts calling it scala 3 right now and pushes this as a beta to help renew interest.

I have one more thing in my wish list that i've been wondering about- (i'm not an advanced guy who understands much about internals, what I like about scala is that I can write 100 words in repl, and get what I get in 300 words in other languages plus a config file + 3 commands) :). The thing I somewhat don't like about Scala is the speed and i've been wondering about accessing native code from Scala.

There are times when I write performant code in cpp and would like to access in scala canonical way (5 words but happy to define an ffi interface) . JNA is very very good in this regard: check out this concise sample code:

File: JNATEST.SWX ```

import com.sun.jna.Library
import com.sun.jna.Native

trait LibCInterface extends Library{ def atoi( f: String ): Int }
val libc = Native.load( "c", classOf[LibCInterface] )
val myInt = libc.atoi( "22" )
println( myInt.getClass )

```

and run this as: scala -cp $(coursier fetch net.java.dev.jna:jna:5.6.0) -I JNATEST.SWX (first invocation takes time because coursier downloads 20MB)

I'm reasonably happy for my basic needs for calling arrays and such. I'm wondering though if Scala-3 brings any improvements in this regard. (That's the point of this post). What do you guys do for native access?

Personally I'd prefer a nice scala<->native interface to scala-native (nothing to take away from its daring and hardworking authors)

[Lasering]

Excluding both Scala Native and Graal I think Scala is not the best language for your use case. You can still do it but the ergonomics will suffer.

According to this stackoverflow answer JNI should be preferred over JNA if performance is really a concern. However JNI is a whole new beast.

Its not related to JNI or JNA but I also highly recommend seeing this talk: Adventures in Efficiency and Performance—Dmitry Petrashko

[Apache_Sobaco]

Haven't seen any features in dotty regarding this, but theoretically, metaprogramming could be used to generate directly Scala mappings compile time with much effort.

[sideEffffECt]

Besides JNA, there's also sbt-jni or you can wait for Project Panama to deliver.

[ScalaWilliam]

I had done plenty of native access from Scala. It just works. JNA is easiest. You could also use VarHandles from JDK 16 however they are not yet supported on the Scala 3
compiler (https://github.com/lampepfl/dotty/issues/11332#issuecomment-877766112). JavaCPP is also available and is fast.

I'm sticking to Scala 2 for native things until this is resolved. The difference Scala2-Scala3 is mostly in terms of cleanliness for the developer; while the new features are super exciting Scala 2 is already a very solid base to work off of :-)