MainGenericRunner should work almost

Author: KacperFKorban

compiler/src/MainGenericRunner.scala

@@ -0,0 +1,112 @@
+package dotty.tools
+
+import scala.annotation.tailrec
+import scala.io.Source
+import scala.util.Try
+import scala.util.matching.Regex
+import java.net.URLClassLoader
+
+enum ExecuteMode:
+  case Guess
+  case Script
+  case Repl
+  case Run
+
+case class Settings(
+  verbose: Boolean = false,
+  classPath: List[String] = List.empty,
+  executeMode: ExecuteMode = ExecuteMode.Guess,
+  exitCode: Int = 0,
+  residualArgs: List[String] = List.empty,
+  scriptArgs: List[String] = List.empty,
+  targetScript: String = "",
+) {
+  def withExecuteMode(em: ExecuteMode): Settings = this.executeMode match
+    case ExecuteMode.Guess =>
+      this.copy(executeMode = em)
+    case _ =>
+      println(s"execute_mode==[$executeMode], attempted overwrite by [$em]")
+      this.copy(exitCode = 1)
+  end withExecuteMode
+
+  def withResidualArgs(args: String*): Settings =
+    this.copy(residualArgs = residualArgs.appendedAll(args.toList))
+
+  def withScriptArgs(args: String*): Settings =
+    this.copy(scriptArgs = scriptArgs.appendedAll(args.toList))
+
+  def withTargetScript(file: String): Settings =
+    Try(Source.fromFile(file)).toOption match
+      case Some(_) => this.copy(targetScript = file)
+      case None      =>
+        println(s"not found $file")
+        this.copy(exitCode = 2)
+  end withTargetScript
+}
+
+object MainGenericRunner {
+
+  val shebangscala: Regex = """#!.*scala""".r
+
+  @tailrec
+  def process(args: List[String], settings: Settings): Settings = args match
+    case Nil =>
+      settings
+    case "-repl" :: tail =>
+      process(tail, settings.withExecuteMode(ExecuteMode.Repl))
+    case "-run" :: tail =>
+      process(tail, settings.withExecuteMode(ExecuteMode.Run))
+    case ("-cp" | "-classpath" | "--classpath") :: cp :: tail =>
+      process(tail, settings.copy(classPath = settings.classPath.appended(cp)))
+    case ("-version" | "--version") :: _ =>
+      settings.copy(
+        executeMode = ExecuteMode.Repl,
+        residualArgs = List("-version")
+      )
+    case ("-v" | "-verbose" | "--verbose") :: tail =>
+      process(
+        tail,
+        settings.copy(
+          verbose = true,
+          residualArgs = settings.residualArgs :+ "-verbose"
+        )
+      )
+    case arg :: tail =>
+      val line = Try(Source.fromFile(arg).getLines.toList).toOption.flatMap(_.headOption)
+      val newSettings = if arg.endsWith(".scala") || arg.endsWith(".sc") || (line.nonEmpty && shebangscala.matches(line.get))
+        then {
+          settings
+            .withExecuteMode(ExecuteMode.Script)
+            .withTargetScript(arg)
+            .withScriptArgs(tail*)
+        } else
+          settings.withResidualArgs(arg)
+      process(tail, newSettings.withResidualArgs(arg))
+
+  def main(args: Array[String]): Unit =
+    val settings = process(args.toList, Settings())
+    if settings.exitCode != 0 then System.exit(settings.exitCode)
+    settings.executeMode match
+      case ExecuteMode.Repl =>
+        val properArgs =
+          List("-classpath", settings.classPath.mkString(";")).filter(Function.const(settings.classPath.nonEmpty))
+            ++ settings.residualArgs
+        repl.Main.main(properArgs.toArray)
+      case ExecuteMode.Run =>
+        val properArgs =
+          List("-classpath", settings.classPath.mkString(";")).filter(Function.const(settings.classPath.nonEmpty))
+            ++ settings.residualArgs
+        //TODO this is just a java proxy?
+      case ExecuteMode.Script =>
+        val properArgs =
+          List("classpath", settings.classPath.mkString(";")).filter(Function.const(settings.classPath.nonEmpty))
+            ++ settings.residualArgs
+            ++ List("-script", settings.targetScript)
+            ++ settings.scriptArgs
+        scripting.Main.main(properArgs.toArray)
+      case ExecuteMode.Guess =>
+        val properArgs =
+          List("-classpath", settings.classPath.mkString(";")).filter(Function.const(settings.classPath.nonEmpty))
+            ++ settings.residualArgs
+        repl.Main.main(properArgs.toArray)
+}

compiler/src/dotty/tools/scripting/Main.scala

@@ -2,7 +2,7 @@ package dotty.tools.scripting
 
 import java.io.File
 import java.nio.file.{Path, Paths}
-import dotty.tools.dotc.config.Properties.isWin 
+import dotty.tools.dotc.config.Properties.isWin
 
 /** Main entry point to the Scripting execution engine */
 object Main:
@@ -87,7 +87,7 @@ object Main:
         case s if s.startsWith("./") => s.drop(2)
         case s => s
       }
-   
+
     // convert to absolute path relative to cwd.
     def absPath: String = norm match
       case str if str.isAbsolute => norm