replpp.scripting.WrapForMainArgs.scala Maven / Gradle / Ivy

Go to download
package replpp.scripting

/** So that we can execute the given script and potentially handle parameters, we wrap it in some code using
 * https://github.com/com-lihaoyi/mainargs  */
object WrapForMainArgs {

  /** linesBeforeWrappedCode: allows us to adjust line numbers in error reporting... */
  case class WrappingResult(fullScript: String, linesBeforeWrappedCode: Int)

  def apply(scriptCode: String): WrappingResult = {
    var linesBeforeWrappedCode = 0
    val mainImpl =
      if (scriptCode.contains("@main")) {
        scriptCode
      } else {
        linesBeforeWrappedCode += 1
        s"""@main def _execMain(): Unit = {
           |$scriptCode
           |}""".stripMargin
      }

    linesBeforeWrappedCode += codeBefore.lines().count().toInt
    val fullScript =
      s"""$codeBefore
         |$mainImpl
         |
         |  def ${ScriptingDriver.MainMethodName}(args: Array[String]): Unit = {
         |    mainargs.ParserForMethods(this).runOrExit(args.toSeq)
         |  }
         |}
         |""".stripMargin

    WrappingResult(fullScript, linesBeforeWrappedCode)
  }

  private val codeBefore =
    s"""import replpp.shaded.mainargs
       |import mainargs.main // intentionally shadow any potentially given @main
       |
       |// ScriptingDriver expects an object with a predefined name and a main entrypoint method
       |object ${ScriptingDriver.MainClassName} {""".stripMargin

}