Read settings into compiled scala app from a scala script

Question
1

Is there an easy way to execute a Scala script from within a compiled Scala application and make the variables available to the compiled application?

2

Could your Scala scripts expose a particular interface/trait? You may be able to do something a la ‘on the fly’ compiled plugins.

3

You can use scala.tools.nsc.ScriptRunner to run scripts.

You can use a singleton to store and retrieve values.

4

This probably does not qualify as easy:

$ cat namer.scala

import util.Properties.userName

greeting = s"Hello, $userName"
$ scala

     ________ ___   / /  ___  
    / __/ __// _ | / /  / _ | 
  __\ \/ /__/ __ |/ /__/ __ | 
 /____/\___/_/ |_/____/_/ | | 
                          |/  version 2.12.4

scala> import javax.script._
import javax.script._

scala> val engine = new ScriptEngineManager().getEngineByName("scala")
engine: javax.script.ScriptEngine = scala.tools.nsc.interpreter.Scripted@13ddaffb

scala> val b = engine.getBindings(ScriptContext.ENGINE_SCOPE)
b: javax.script.Bindings = javax.script.SimpleBindings@7fdff56b

scala> b.values
res0: java.util.Collection[Object] = []

scala> b.put("greeting", "none")
res1: Object = null

scala> b.values
res2: java.util.Collection[Object] = [none]

scala> import java.nio.file._
import java.nio.file._

scala> engine.
createBindings   eval   get   getBindings   getContext   getFactory   put   setBindings   setContext

scala> engine.eval
                                                                        def eval(x$1: java.io.Reader,x$2: javax.script.Bindings): Object   
def eval(x$1: String,x$2: javax.script.Bindings): Object                def eval(x$1: java.io.Reader): Object                              
def eval(x$1: java.io.Reader,x$2: javax.script.ScriptContext): Object   def eval(x$1: String,x$2: javax.script.ScriptContext): Object      
def eval(x$1: String): Object                                                                                                              

scala> engine.eval(Files.newBufferedReader(Paths.get("namer.scala")))
res3: Object = Hello, amarki

scala> b.values
res4: java.util.Collection[Object] = [Hello, amarki]

scala> b.entrySet
res5: java.util.Set[java.util.Map.Entry[String,Object]] = [greeting=Hello, amarki]