Scala on the Java binding

Scala calls the arena's generated Java core binding directly. Import clunkyard._; clunkyard.jar owns all C ABI conversion. There is no copied SDK or separate protocol, tracking or geometry implementation.

Compile with scalac -cp /opt/clunkyard/sdk/bindings/java/clunkyard.jar -d classes Bot.scala. Run with java --enable-native-access=ALL-UNNAMED -cp classes:/opt/clunkyard/sdk/bindings/java/clunkyard.jar:/usr/share/scala-2.11/lib/scala-library.jar Bot. The binding loads libclunkyard.so.2, or CLUNKYARD_LIB.

Subsystems and facts are methods. Escape the Scala keyword as this.`match`(). Absent results use Java Optional, OptionalDouble or OptionalInt. Controls take their fields in order or a builder such as Drive.throttle(0.5).turn(0.2); fields merge in a turn. Throw new Forfeit(code, message) to forfeit; other exceptions are logged and send the controls already set. Clunkyard.play plays lines in memory.

A tiny robot

import clunkyard._

class Bot extends Robot {
  override def onTurn(): Unit = {
    val target = sensors().nearest().orElse(null)
    if (target == null) {
      drive().set(Drive.throttle(0.75).turn(0.25))
      scanner().set(me().heading(), 40)
      status().set("SEARCH", scanner().last().arc())
    } else {
      val power = gun().powerForFlightTime(target.range(), 1)
      val aim = gun().lead(target, power).orElse(null)
      if (aim == null) gun().aim(target.bearing(), target.elevation())
      else gun().aim(aim.heading(), aim.pitch())
      if (gun().canFire(power, 10)) gun().fire(power)
      drive().set(Drive.throttle(0.5).turn(angles().clamp(angles().angleDiff(target.bearing(), me().heading()))))
      scanner().set(target.bearing(), 10)
      status().set("TRACK", target.range())
    }
  }
}
object Bot { def main(args: Array[String]): Unit = Clunkyard.run(new Bot) }

make test SDK=... compiles Scala against the shared binding and runs its full API conformance transcript. The README example participates in the cross-language act identity check.

Names

Every entry of the robot API 2.0.0 in Scala. names.md has every language side by side.

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