From da3b82d01d1c42c4820f09195e3937d50b1d521c Mon Sep 17 00:00:00 2001
From: Michael Pollmeier <michael@michaelpollmeier.com>
Date: Sat, 16 Nov 2024 14:16:44 +0100
Subject: [PATCH 01/11] add config option to run code on startup

---
 core/src/main/scala/replpp/Config.scala       | 19 +++++++++++++++++--
 core/src/test/scala/replpp/ConfigTests.scala  |  3 +++
 .../src/main/scala/replpp/server/Config.scala |  1 +
 .../scala/replpp/server/ConfigTests.scala     |  2 ++
 4 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/core/src/main/scala/replpp/Config.scala b/core/src/main/scala/replpp/Config.scala
index 5395a8ca..fcb45ab9 100644
--- a/core/src/main/scala/replpp/Config.scala
+++ b/core/src/main/scala/replpp/Config.scala
@@ -8,7 +8,8 @@ import replpp.shaded.scopt.OParserBuilder
 import java.nio.file.Path
 
 case class Config(
-  predefFiles: Seq[Path] = Nil,
+  predefFiles: Seq[Path] = Nil, // these files will be precompiled and added to the classpath
+  runBefore: Seq[String] = Nil, // these statements will be interpreted on startup
   nocolors: Boolean = false,
   verbose: Boolean = false,
   classpathConfig: Config.ForClasspath = Config.ForClasspath(),
@@ -41,6 +42,10 @@ case class Config(
       add("--predef", predefFile.toString)
     }
 
+    runBefore.foreach { runBefore =>
+      add("--runBefore", runBefore)
+    }
+
     if (nocolors) add("--nocolors")
     if (verbose) add("--verbose")
 
@@ -103,6 +108,7 @@ object Config {
     OParser.sequence(
       programName("scala-repl-pp"),
       opts.predef((x, c) => c.copy(predefFiles = c.predefFiles :+ x)),
+      opts.runBefore((x, c) => c.copy(runBefore = c.runBefore :+ x)),
       opts.nocolors((_, c) => c.copy(nocolors = true)),
       opts.verbose((_, c) => c.copy(verbose = true)),
       opts.classpathEntry((x, c) => c.copy(classpathConfig = c.classpathConfig.copy(additionalClasspathEntries = c.classpathConfig.additionalClasspathEntries :+ x))),
@@ -142,7 +148,16 @@ object Config {
         .unbounded()
         .optional()
         .action(action)
-        .text("import additional script files on startup - may be passed multiple times")
+        .text("given source files will be compiled and added to classpath - this may be passed multiple times")
+    }
+
+    def runBefore[C](using builder: OParserBuilder[C])(action: Action[String, C]) = {
+      builder.opt[String]("runBefore")
+        .valueName("val foo = 42")
+        .unbounded()
+        .optional()
+        .action(action)
+        .text("given code will be executed on startup - this may be passed multiple times")
     }
 
     def nocolors[C](using builder: OParserBuilder[C])(action: Action[Unit, C]) = {
diff --git a/core/src/test/scala/replpp/ConfigTests.scala b/core/src/test/scala/replpp/ConfigTests.scala
index 8f32c74a..ee48586b 100644
--- a/core/src/test/scala/replpp/ConfigTests.scala
+++ b/core/src/test/scala/replpp/ConfigTests.scala
@@ -19,6 +19,7 @@ class ConfigTests extends AnyWordSpec with Matchers {
   "asJavaArgs (inverse of Config.parse)" in {
     val config = Config(
       predefFiles = List(Paths.get("/some/path/predefFile1"), Paths.get("/some/path/predefFile2")),
+      runBefore = List("val foo = 42", "println(foo)"),
       nocolors = true,
       verbose = true,
       classpathConfig = Config.ForClasspath(
@@ -39,6 +40,8 @@ class ConfigTests extends AnyWordSpec with Matchers {
     javaArgs shouldBe Seq(
       "--predef", Paths.get("/some/path/predefFile1").toString,
       "--predef", Paths.get("/some/path/predefFile2").toString,
+      "--runBefore", "val foo = 42",
+      "--runBefore", "println(foo)",
       "--nocolors",
       "--verbose",
       "--classpathEntry", "cp1",
diff --git a/server/src/main/scala/replpp/server/Config.scala b/server/src/main/scala/replpp/server/Config.scala
index 48afa047..eaaaafec 100644
--- a/server/src/main/scala/replpp/server/Config.scala
+++ b/server/src/main/scala/replpp/server/Config.scala
@@ -16,6 +16,7 @@ object Config {
     val parser = OParser.sequence(
       programName("scala-repl-pp-server"),
       replpp.Config.opts.predef((x, c) => c.copy(baseConfig = c.baseConfig.copy(predefFiles = c.baseConfig.predefFiles :+ x))),
+      replpp.Config.opts.runBefore((x, c) => c.copy(baseConfig = c.baseConfig.copy(runBefore = c.baseConfig.runBefore :+ x))),
       replpp.Config.opts.verbose((_, c) => c.copy(baseConfig = c.baseConfig.copy(verbose = true))),
       replpp.Config.opts.inheritClasspath((_, c) => c.copy(baseConfig = c.baseConfig.copy(classpathConfig = c.baseConfig.classpathConfig.copy(inheritClasspath = true)))),
       replpp.Config.opts.classpathIncludesEntry((x, c) => {
diff --git a/server/src/test/scala/replpp/server/ConfigTests.scala b/server/src/test/scala/replpp/server/ConfigTests.scala
index 55924ab6..dea6d3a4 100644
--- a/server/src/test/scala/replpp/server/ConfigTests.scala
+++ b/server/src/test/scala/replpp/server/ConfigTests.scala
@@ -17,6 +17,7 @@ class ConfigTests extends AnyWordSpec with Matchers {
       "--server-auth-password", "test-pass",
       "--verbose",
       "--predef", "test-predef.sc",
+      "--runBefore", "val foo = 42",
     ))
     parsed.serverHost shouldBe "testHost"
     parsed.serverPort shouldBe 42
@@ -24,6 +25,7 @@ class ConfigTests extends AnyWordSpec with Matchers {
     parsed.serverAuthPassword shouldBe Some("test-pass")
     parsed.baseConfig.verbose shouldBe true
     parsed.baseConfig.predefFiles shouldBe Seq(Paths.get("test-predef.sc"))
+    parsed.baseConfig.runBefore shouldBe Seq("val foo = 42")
   }
 
 }

From f0852d0f8e1145273e64fd3ace942d82ef567919 Mon Sep 17 00:00:00 2001
From: Michael Pollmeier <michael@michaelpollmeier.com>
Date: Mon, 18 Nov 2024 08:28:21 +0100
Subject: [PATCH 02/11] scripting driver: print warning for given `runBefore`
 code

---
 .../main/scala/replpp/scripting/NonForkingScriptRunner.scala | 5 +++++
 core/src/main/scala/replpp/scripting/ScriptingDriver.scala   | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/core/src/main/scala/replpp/scripting/NonForkingScriptRunner.scala b/core/src/main/scala/replpp/scripting/NonForkingScriptRunner.scala
index 1fcb91c4..51dde94f 100644
--- a/core/src/main/scala/replpp/scripting/NonForkingScriptRunner.scala
+++ b/core/src/main/scala/replpp/scripting/NonForkingScriptRunner.scala
@@ -1,5 +1,6 @@
 package replpp.scripting
 
+import org.slf4j.LoggerFactory
 import replpp.{Config, allPredefFiles, allSourceFiles}
 
 import java.nio.file.Files
@@ -14,6 +15,7 @@ import scala.util.{Failure, Success}
   * the NonForkingScriptRunner :)
   */
 object NonForkingScriptRunner {
+  private val logger = LoggerFactory.getLogger(getClass)
 
   def main(args: Array[String]): Unit = {
     val config = Config.parse(args)
@@ -36,6 +38,9 @@ object NonForkingScriptRunner {
       commandArgs ++ parameterArgs
     }
 
+    if (config.runBefore.nonEmpty)
+      logger.warn(s"ScriptingDriver does not support `runBefore` code, the given ${config.runBefore.size} statements will be ignored")
+
     val verboseEnabled = replpp.verboseEnabled(config)
     new ScriptingDriver(
       compilerArgs = replpp.compilerArgs(config) :+ "-nowarn",
diff --git a/core/src/main/scala/replpp/scripting/ScriptingDriver.scala b/core/src/main/scala/replpp/scripting/ScriptingDriver.scala
index 4602a17c..299fdd21 100644
--- a/core/src/main/scala/replpp/scripting/ScriptingDriver.scala
+++ b/core/src/main/scala/replpp/scripting/ScriptingDriver.scala
@@ -17,7 +17,7 @@ import scala.util.{Failure, Try}
   * Runs a given script on the current JVM.
   *
   * Similar to dotty.tools.scripting.ScriptingDriver, but simpler and faster.
-  * Main difference: we don't (need to) recursively look for main method entrypoints in the entire classpath,
+  * Main difference: we don't (need to) recursively look for main method entry points in the entire classpath,
   * because we have a fixed class and method name that ScriptRunner uses when it embeds the script and predef code.
   * */
 class ScriptingDriver(compilerArgs: Array[String], predefFiles: Seq[Path], scriptFile: Path, scriptArgs: Array[String], verbose: Boolean) {

From 0d1d12fb322d79bd6d2c96bd97b485980b01fb9c Mon Sep 17 00:00:00 2001
From: Michael Pollmeier <michael@michaelpollmeier.com>
Date: Mon, 18 Nov 2024 15:00:31 +0100
Subject: [PATCH 03/11] runBefore: invoke

---
 build.sbt                                        |  2 +-
 core/src/main/scala/replpp/Config.scala          |  2 +-
 .../src/main/scala/replpp/InteractiveShell.scala | 13 +++++++------
 core/src/main/scala/replpp/package.scala         | 16 +++++++---------
 4 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/build.sbt b/build.sbt
index 788fa53a..93fde41f 100644
--- a/build.sbt
+++ b/build.sbt
@@ -26,7 +26,7 @@ lazy val core = project.in(file("core"))
     executableScriptName := "srp",
     libraryDependencies ++= Seq(
       "org.scala-lang" %% "scala3-compiler" % scalaVersion.value,
-      "org.slf4j"       % "slf4j-simple" % "2.0.13" % Optional,
+      "org.slf4j"       % "slf4j-simple"    % "2.0.16" % Optional,
     ),
     assemblyJarName := "srp.jar", // TODO remove the '.jar' suffix - when doing so, it doesn't work any longer
   )
diff --git a/core/src/main/scala/replpp/Config.scala b/core/src/main/scala/replpp/Config.scala
index fcb45ab9..5605b0f3 100644
--- a/core/src/main/scala/replpp/Config.scala
+++ b/core/src/main/scala/replpp/Config.scala
@@ -153,7 +153,7 @@ object Config {
 
     def runBefore[C](using builder: OParserBuilder[C])(action: Action[String, C]) = {
       builder.opt[String]("runBefore")
-        .valueName("val foo = 42")
+        .valueName("'val foo = 42'")
         .unbounded()
         .optional()
         .action(action)
diff --git a/core/src/main/scala/replpp/InteractiveShell.scala b/core/src/main/scala/replpp/InteractiveShell.scala
index b819ee61..68f040b7 100644
--- a/core/src/main/scala/replpp/InteractiveShell.scala
+++ b/core/src/main/scala/replpp/InteractiveShell.scala
@@ -2,6 +2,7 @@ package replpp
 
 import dotty.tools.repl.State
 
+import java.lang.System.lineSeparator
 import scala.util.control.NoStackTrace
 
 object InteractiveShell {
@@ -21,22 +22,22 @@ object InteractiveShell {
     )
 
     val initialState: State = replDriver.initialState
-    val predefCode = DefaultPredef
+    val runBeforeLines = (DefaultRunBeforeLines ++ config.runBefore).mkString(lineSeparator)
     val state: State = {
       if (verboseEnabled(config)) {
         println(s"compiler arguments: ${compilerArgs.mkString(",")}")
-        println(predefCode)
-        replDriver.run(predefCode)(using initialState)
+        println(runBeforeLines)
+        replDriver.run(runBeforeLines)(using initialState)
       } else {
-        replDriver.runQuietly(predefCode)(using initialState)
+        replDriver.runQuietly(runBeforeLines)(using initialState)
       }
     }
 
-    if (predefCode.nonEmpty && state.objectIndex != 1) {
+    if (runBeforeLines.nonEmpty && state.objectIndex != 1) {
       throw new AssertionError(s"compilation error for predef code - error should have been reported above ^") with NoStackTrace
     }
 
     replDriver.runUntilQuit(using state)()
   }
   
-}
\ No newline at end of file
+}
diff --git a/core/src/main/scala/replpp/package.scala b/core/src/main/scala/replpp/package.scala
index 8a1f91c9..f6ba9076 100644
--- a/core/src/main/scala/replpp/package.scala
+++ b/core/src/main/scala/replpp/package.scala
@@ -9,21 +9,20 @@ package object replpp {
   val VerboseEnvVar    = "SCALA_REPL_PP_VERBOSE"
   lazy val pwd: Path = Paths.get(".").toAbsolutePath
   lazy val home: Path = Paths.get(System.getProperty("user.home"))
-  lazy val globalPredefFile = home.resolve(".scala-repl-pp.sc")
-  lazy val globalPredefFileMaybe = Option(globalPredefFile).filter(Files.exists(_))
+  lazy val globalRunBeforeFile = home.resolve(".scala-repl-pp.sc")
+  lazy val globalRunBeforeFileMaybe = Option(globalRunBeforeFile).filter(Files.exists(_))
 
-  private[replpp] def DefaultPredefLines(using colors: Colors) = {
+  private[replpp] def DefaultRunBeforeLines(using colors: Colors) = {
     val colorsImport = colors match {
       case Colors.BlackWhite => "replpp.Colors.BlackWhite"
       case Colors.Default => "replpp.Colors.Default"
     }
     Seq(
       "import replpp.Operators.*",
-      s"given replpp.Colors = $colorsImport"
+      s"given replpp.Colors = $colorsImport",
     )
   }
 
-  private[replpp] def DefaultPredef(using Colors) = DefaultPredefLines.mkString(lineSeparator)
 
   /** verbose mode can either be enabled via the config, or the environment variable `SCALA_REPL_PP_VERBOSE=true` */
   def verboseEnabled(config: Config): Boolean = {
@@ -49,9 +48,8 @@ package object replpp {
   def allPredefFiles(config: Config): Seq[Path] = {
     val allPredefFiles  = mutable.Set.empty[Path]
     allPredefFiles ++= config.predefFiles
-    globalPredefFileMaybe.foreach(allPredefFiles.addOne)
 
-    // the directly resolved predef files might reference additional files via `using` directive
+    // the directly referenced predef files might reference additional files via `using` directive
     val predefFilesDirect = allPredefFiles.toSet
     predefFilesDirect.foreach { predefFile =>
       val importedFiles = UsingDirectives.findImportedFilesRecursively(predefFile, visited = allPredefFiles.toSet)
@@ -68,11 +66,11 @@ package object replpp {
   }
 
   def allSourceLines(config: Config): Seq[String] =
-    allSourceFiles(config).flatMap(linesFromFile)
+    allSourceFiles(config).flatMap(linesFromFile) ++ config.runBefore
 
   /** precompile given predef files (if any) and update Config to include the results in the classpath */
   def precompilePredefFiles(config: Config): Config = {
-    val allPredefFiles = (config.predefFiles :+ globalPredefFile).filter(Files.exists(_))
+    val allPredefFiles = (config.predefFiles :+ globalRunBeforeFile).filter(Files.exists(_))
     if (allPredefFiles.nonEmpty) {
       val predefClassfilesDir = new SimpleDriver().compileAndGetOutputDir(
         replpp.compilerArgs(config),

From 9dd60c951d9c6362e0b258a6aca9b0ae0c348e2f Mon Sep 17 00:00:00 2001
From: Michael Pollmeier <michael@michaelpollmeier.com>
Date: Mon, 18 Nov 2024 15:07:04 +0100
Subject: [PATCH 04/11] back to println for warning printing to avoid
 classloader issues

---
 .../scala/replpp/scripting/NonForkingScriptRunner.scala     | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/core/src/main/scala/replpp/scripting/NonForkingScriptRunner.scala b/core/src/main/scala/replpp/scripting/NonForkingScriptRunner.scala
index 51dde94f..ade7690b 100644
--- a/core/src/main/scala/replpp/scripting/NonForkingScriptRunner.scala
+++ b/core/src/main/scala/replpp/scripting/NonForkingScriptRunner.scala
@@ -1,6 +1,5 @@
 package replpp.scripting
 
-import org.slf4j.LoggerFactory
 import replpp.{Config, allPredefFiles, allSourceFiles}
 
 import java.nio.file.Files
@@ -15,7 +14,6 @@ import scala.util.{Failure, Success}
   * the NonForkingScriptRunner :)
   */
 object NonForkingScriptRunner {
-  private val logger = LoggerFactory.getLogger(getClass)
 
   def main(args: Array[String]): Unit = {
     val config = Config.parse(args)
@@ -39,7 +37,7 @@ object NonForkingScriptRunner {
     }
 
     if (config.runBefore.nonEmpty)
-      logger.warn(s"ScriptingDriver does not support `runBefore` code, the given ${config.runBefore.size} statements will be ignored")
+      println(s"[WARNING] ScriptingDriver does not support `runBefore` code, the given ${config.runBefore.size} statements will be ignored")
 
     val verboseEnabled = replpp.verboseEnabled(config)
     new ScriptingDriver(
@@ -57,4 +55,4 @@ object NonForkingScriptRunner {
     }
   }
 
-}
\ No newline at end of file
+}

From 2267e919cd6e41082cd46237f0f5ee331d3a2fec Mon Sep 17 00:00:00 2001
From: Michael Pollmeier <michael@michaelpollmeier.com>
Date: Mon, 18 Nov 2024 15:38:18 +0100
Subject: [PATCH 05/11] cleanup and update tests

---
 .../main/scala/replpp/UsingDirectives.scala   | 16 -------------
 core/src/test/scala/replpp/PredefTests.scala  | 23 ++++++++-----------
 2 files changed, 9 insertions(+), 30 deletions(-)

diff --git a/core/src/main/scala/replpp/UsingDirectives.scala b/core/src/main/scala/replpp/UsingDirectives.scala
index 03cb97b3..af5fa5c6 100644
--- a/core/src/main/scala/replpp/UsingDirectives.scala
+++ b/core/src/main/scala/replpp/UsingDirectives.scala
@@ -25,22 +25,6 @@ object UsingDirectives {
   def findImportedFiles(lines: IterableOnce[String], rootPath: Path): Seq[Path] =
     scanFor(FileDirective, lines).iterator.map(resolveFile(rootPath, _)).toSeq
 
-  def findImportedFilesRecursively(lines: IterableOnce[String], rootPath: Path): Seq[Path] = {
-    val results = Seq.newBuilder[Path]
-    val visited = mutable.Set.empty[Path]
-
-    findImportedFiles(lines, rootPath).foreach { file =>
-      results += file
-      visited += file
-
-      val recursiveFiles = findImportedFilesRecursively(file, visited.toSet)
-      results ++= recursiveFiles
-      visited ++= recursiveFiles
-    }
-
-    results.result().distinct
-  }
-
   def findDeclaredDependencies(lines: IterableOnce[String]): Seq[String] =
     scanFor(LibDirective, lines)
 
diff --git a/core/src/test/scala/replpp/PredefTests.scala b/core/src/test/scala/replpp/PredefTests.scala
index cd907513..85419e6f 100644
--- a/core/src/test/scala/replpp/PredefTests.scala
+++ b/core/src/test/scala/replpp/PredefTests.scala
@@ -7,24 +7,19 @@ class PredefTests extends AnyWordSpec with Matchers {
   given Colors = Colors.BlackWhite
 
   "recursively resolve `//> using file` directive" in {
-    val script = os.temp("val mainScript = 5")
-    val additionalScript1 = os.temp("val additionalScript1 = 10")
-    val additionalScript2 = os.temp("val additionalScript2 = 20")
+    val additionalFile2 = os.temp(
+      """val predef2 = 10"""
+    )
+    val additionalFile1 = os.temp(
+      s"""//> using file $additionalFile2
+        |val predef1 = 20""".stripMargin)
     val predefFile = os.temp(
-      s"""//> using file $additionalScript1
+      s"""//> using file $additionalFile1
          |val predefCode = 1
-         |//> using file $additionalScript2
          |""".stripMargin)
 
-    allSourceLines(Config(predefFiles = Seq(predefFile.toNIO), scriptFile = Some(script.toNIO))).sorted shouldBe
-      Seq(
-        s"//> using file $additionalScript1",
-        s"//> using file $additionalScript2",
-        "val additionalScript1 = 10",
-        "val additionalScript2 = 20",
-        "val mainScript = 5",
-        "val predefCode = 1",
-      ).sorted
+    UsingDirectives.findImportedFilesRecursively(predefFile.toNIO).sorted shouldBe
+      Seq(additionalFile1, additionalFile2).map(_.toNIO).sorted
   }
 
   "recursively resolve `//> using file` directive - with recursive loops" in {

From 99289a156488d8da94799e24c596d396648e8f1b Mon Sep 17 00:00:00 2001
From: Michael Pollmeier <michael@michaelpollmeier.com>
Date: Mon, 18 Nov 2024 15:51:48 +0100
Subject: [PATCH 06/11] integrate / consolidate tests

---
 core/src/test/scala/replpp/PredefTests.scala  | 54 ------------------
 .../scala/replpp/UsingDirectivesTests.scala   | 55 +++++++++++--------
 2 files changed, 33 insertions(+), 76 deletions(-)
 delete mode 100644 core/src/test/scala/replpp/PredefTests.scala

diff --git a/core/src/test/scala/replpp/PredefTests.scala b/core/src/test/scala/replpp/PredefTests.scala
deleted file mode 100644
index 85419e6f..00000000
--- a/core/src/test/scala/replpp/PredefTests.scala
+++ /dev/null
@@ -1,54 +0,0 @@
-package replpp
-
-import org.scalatest.matchers.should.Matchers
-import org.scalatest.wordspec.AnyWordSpec
-
-class PredefTests extends AnyWordSpec with Matchers {
-  given Colors = Colors.BlackWhite
-
-  "recursively resolve `//> using file` directive" in {
-    val additionalFile2 = os.temp(
-      """val predef2 = 10"""
-    )
-    val additionalFile1 = os.temp(
-      s"""//> using file $additionalFile2
-        |val predef1 = 20""".stripMargin)
-    val predefFile = os.temp(
-      s"""//> using file $additionalFile1
-         |val predefCode = 1
-         |""".stripMargin)
-
-    UsingDirectives.findImportedFilesRecursively(predefFile.toNIO).sorted shouldBe
-      Seq(additionalFile1, additionalFile2).map(_.toNIO).sorted
-  }
-
-  "recursively resolve `//> using file` directive - with recursive loops" in {
-    val script = os.temp("val mainScript = 5")
-    val additionalScript1 = os.temp(suffix = "-script1")
-    val additionalScript2 = os.temp(suffix = "-script2")
-
-    os.write.over(additionalScript1,
-      s"""//> using file $additionalScript2
-         |val additionalScript1 = 10""".stripMargin)
-    os.write.over(additionalScript2,
-      s"""//> using file $additionalScript1
-         |val additionalScript2 = 20
-         |""".stripMargin)
-
-    val predefFile = os.temp(
-      s"""//> using file $additionalScript1
-         |val predefCode = 1
-         |""".stripMargin)
-
-    // most importantly, this should not loop endlessly due to the recursive imports
-    allSourceLines(Config(predefFiles = Seq(predefFile.toNIO), scriptFile = Some(script.toNIO))).distinct.sorted shouldBe
-      Seq(
-        s"//> using file $additionalScript1",
-        s"//> using file $additionalScript2",
-        "val additionalScript1 = 10",
-        "val additionalScript2 = 20",
-        "val mainScript = 5",
-        "val predefCode = 1",
-      ).sorted
-  }
-}
diff --git a/core/src/test/scala/replpp/UsingDirectivesTests.scala b/core/src/test/scala/replpp/UsingDirectivesTests.scala
index c9dbfcf2..ed92a043 100644
--- a/core/src/test/scala/replpp/UsingDirectivesTests.scala
+++ b/core/src/test/scala/replpp/UsingDirectivesTests.scala
@@ -25,30 +25,41 @@ class UsingDirectivesTests extends AnyWordSpec with Matchers {
     results should not contain Paths.get("./commented_out.sc")
   }
 
-  "find imported files recursively from given source" in {
-    val script1 = os.temp("val foo = 42")
-    val script2 = os.temp(
-      s"""//> using file $script1
-         |val bar = 42""".stripMargin)
-
-    val rootPath = Paths.get(".")
-    val source = s"//> using file $script2"
-
-    val results = UsingDirectives.findImportedFilesRecursively(Seq(source), rootPath)
-    results should contain(script1.toNIO)
-    results should contain(script2.toNIO)
+  "recursively resolve `//> using file` directive" in {
+    val additionalFile2 = os.temp(
+      contents = """val predef2 = 10""",
+      suffix = "additionalFile2"
+    )
+    val additionalFile1 = os.temp(
+      contents = s"""//> using file $additionalFile2
+                    |val predef1 = 20""".stripMargin,
+      suffix = "additionalFile1"
+    )
+    val predefFile = os.temp(
+      contents = s"""//> using file $additionalFile1
+                    |val predef0 = 0""".stripMargin)
+
+    UsingDirectives.findImportedFilesRecursively(predefFile.toNIO).sorted shouldBe
+      Seq(additionalFile1, additionalFile2).map(_.toNIO).sorted
   }
 
-  "find imported files recursively from given script" in {
-    val script1 = os.temp("val foo = 42")
-    val script2 = os.temp(
-      s"""//> using file $script1
-         |val bar = 42""".stripMargin)
-    val script3 = os.temp(s"//> using file $script2")
-
-    val results = UsingDirectives.findImportedFilesRecursively(script3.toNIO)
-    results should contain(script1.toNIO)
-    results should contain(script2.toNIO)
+  "recursively resolve `//> using file` directive - and handle recursive loops" in {
+    val additionalFile2 = os.temp(suffix = "additionalFile2")
+    val additionalFile1 = os.temp(suffix = "additionalFile1")
+    val predefFile = os.temp(
+      contents = s"""//> using file $additionalFile1
+                    |val predef0 = 0""".stripMargin)
+
+    os.write.over(additionalFile1,
+      s"""//> using file $additionalFile2
+         |val predef1 = 10""".stripMargin)
+    os.write.over(additionalFile2,
+      s"""//> using file $additionalFile1
+         |val predef2 = 20""".stripMargin)
+
+    UsingDirectives.findImportedFilesRecursively(predefFile.toNIO).sorted shouldBe
+      Seq(additionalFile1, additionalFile2).map(_.toNIO).sorted
+      // most importantly, this should not loop endlessly due to the recursive imports
   }
 
   "find declared dependencies" in {

From 360e247503a35c7eb3269747a284ac04a122b852 Mon Sep 17 00:00:00 2001
From: Michael Pollmeier <michael@michaelpollmeier.com>
Date: Mon, 18 Nov 2024 16:07:35 +0100
Subject: [PATCH 07/11] additional test

---
 core/src/main/scala/replpp/package.scala      | 11 ++++-----
 .../replpp/scripting/ScriptRunnerTests.scala  | 24 ++++++++++++++++++-
 2 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/core/src/main/scala/replpp/package.scala b/core/src/main/scala/replpp/package.scala
index f6ba9076..b1412201 100644
--- a/core/src/main/scala/replpp/package.scala
+++ b/core/src/main/scala/replpp/package.scala
@@ -1,6 +1,5 @@
 import replpp.util.{ClasspathHelper, SimpleDriver, linesFromFile}
 
-import java.lang.System.lineSeparator
 import java.nio.file.{Files, Path, Paths}
 import scala.collection.mutable
 
@@ -23,7 +22,6 @@ package object replpp {
     )
   }
 
-
   /** verbose mode can either be enabled via the config, or the environment variable `SCALA_REPL_PP_VERBOSE=true` */
   def verboseEnabled(config: Config): Boolean = {
     config.verbose ||
@@ -43,7 +41,7 @@ package object replpp {
   /** recursively find all relevant source files from main script, global predef file, 
     * provided predef files, other scripts that were imported with `using file` directive */
   def allSourceFiles(config: Config): Seq[Path] =
-    (allPredefFiles(config) ++ config.scriptFile).distinct.sorted
+    (allPredefFiles(config) ++ config.scriptFile ++ globalRunBeforeFileMaybe).distinct.sorted
 
   def allPredefFiles(config: Config): Seq[Path] = {
     val allPredefFiles  = mutable.Set.empty[Path]
@@ -62,7 +60,7 @@ package object replpp {
       allPredefFiles ++= importedFiles
     }
 
-    allPredefFiles.toSeq.sorted
+    allPredefFiles.toSeq.filter(Files.exists(_)).sorted
   }
 
   def allSourceLines(config: Config): Seq[String] =
@@ -70,11 +68,10 @@ package object replpp {
 
   /** precompile given predef files (if any) and update Config to include the results in the classpath */
   def precompilePredefFiles(config: Config): Config = {
-    val allPredefFiles = (config.predefFiles :+ globalRunBeforeFile).filter(Files.exists(_))
-    if (allPredefFiles.nonEmpty) {
+    if (config.predefFiles.nonEmpty) {
       val predefClassfilesDir = new SimpleDriver().compileAndGetOutputDir(
         replpp.compilerArgs(config),
-        inputFiles = allPredefFiles,
+        inputFiles = allPredefFiles(config),
         verbose = config.verbose
       ).get
       config.withAdditionalClasspathEntry(predefClassfilesDir)
diff --git a/core/src/test/scala/replpp/scripting/ScriptRunnerTests.scala b/core/src/test/scala/replpp/scripting/ScriptRunnerTests.scala
index 9f5a6651..0e56d7d8 100644
--- a/core/src/test/scala/replpp/scripting/ScriptRunnerTests.scala
+++ b/core/src/test/scala/replpp/scripting/ScriptRunnerTests.scala
@@ -129,7 +129,7 @@ class ScriptRunnerTests extends AnyWordSpec with Matchers {
       }.get shouldBe "iwashere-using-file-test3:99"
     }
 
-    "import additional files via `//> using file` recursively" in {
+    "import additional files via `//> using file` recursively from script file" in {
       execTest { testOutputPath =>
         val additionalScript0 = os.temp()
         val additionalScript1 = os.temp()
@@ -149,6 +149,28 @@ class ScriptRunnerTests extends AnyWordSpec with Matchers {
       }.get shouldBe "iwashere-using-file-test4:99"
     }
 
+    "import additional files via `//> using file` recursively from predef file" in {
+      execTest { testOutputPath =>
+        val additionalPredefFile2 = os.temp()
+        val additionalPredefFile1 = os.temp()
+        // should handle recursive loop as well
+        os.write.over(additionalPredefFile2,
+          s"""//> using file $additionalPredefFile1
+             |def foo = 99""".stripMargin)
+        os.write.over(additionalPredefFile1,
+          s"""//> using file $additionalPredefFile2
+             |def bar = foo""".stripMargin)
+        val predefFile = os.temp(s"//> using file $additionalPredefFile1")
+        TestSetup(
+          s"""
+             |import java.nio.file.*
+             |Files.writeString(Path.of("$testOutputPath"), "iwashere-using-file-test4:" + bar)
+             |""".stripMargin,
+          _.copy(predefFiles = Seq(predefFile.toNIO))
+        )
+      }.get shouldBe "iwashere-using-file-test4:99"
+    }
+
     "import additional files: use relative path of dependent script, and import in correct order" in {
       execTest { testOutputPath =>
         val scriptRootDir = os.temp.dir()

From 5da154f86d1837a7efd523debf15870f6fc3b32e Mon Sep 17 00:00:00 2001
From: Michael Pollmeier <michael@michaelpollmeier.com>
Date: Mon, 18 Nov 2024 16:54:20 +0100
Subject: [PATCH 08/11] execute globalRunBeforeFile

---
 core/src/main/scala/replpp/InteractiveShell.scala               | 2 +-
 .../main/scala/replpp/scripting/NonForkingScriptRunner.scala    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/core/src/main/scala/replpp/InteractiveShell.scala b/core/src/main/scala/replpp/InteractiveShell.scala
index 68f040b7..e86d4fba 100644
--- a/core/src/main/scala/replpp/InteractiveShell.scala
+++ b/core/src/main/scala/replpp/InteractiveShell.scala
@@ -22,7 +22,7 @@ object InteractiveShell {
     )
 
     val initialState: State = replDriver.initialState
-    val runBeforeLines = (DefaultRunBeforeLines ++ config.runBefore).mkString(lineSeparator)
+    val runBeforeLines = (DefaultRunBeforeLines ++ globalRunBeforeLines ++ config.runBefore).mkString(lineSeparator)
     val state: State = {
       if (verboseEnabled(config)) {
         println(s"compiler arguments: ${compilerArgs.mkString(",")}")
diff --git a/core/src/main/scala/replpp/scripting/NonForkingScriptRunner.scala b/core/src/main/scala/replpp/scripting/NonForkingScriptRunner.scala
index ade7690b..1d4e64e9 100644
--- a/core/src/main/scala/replpp/scripting/NonForkingScriptRunner.scala
+++ b/core/src/main/scala/replpp/scripting/NonForkingScriptRunner.scala
@@ -1,6 +1,6 @@
 package replpp.scripting
 
-import replpp.{Config, allPredefFiles, allSourceFiles}
+import replpp.{Config, allPredefFiles}
 
 import java.nio.file.Files
 import scala.util.{Failure, Success}

From 60b24cbbcd864fb9063e9f1b7abbe7056a87f363 Mon Sep 17 00:00:00 2001
From: Michael Pollmeier <michael@michaelpollmeier.com>
Date: Mon, 18 Nov 2024 16:54:55 +0100
Subject: [PATCH 09/11] type annotations for readability

---
 core/src/main/scala/replpp/package.scala | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/core/src/main/scala/replpp/package.scala b/core/src/main/scala/replpp/package.scala
index b1412201..332815d4 100644
--- a/core/src/main/scala/replpp/package.scala
+++ b/core/src/main/scala/replpp/package.scala
@@ -8,8 +8,9 @@ package object replpp {
   val VerboseEnvVar    = "SCALA_REPL_PP_VERBOSE"
   lazy val pwd: Path = Paths.get(".").toAbsolutePath
   lazy val home: Path = Paths.get(System.getProperty("user.home"))
-  lazy val globalRunBeforeFile = home.resolve(".scala-repl-pp.sc")
-  lazy val globalRunBeforeFileMaybe = Option(globalRunBeforeFile).filter(Files.exists(_))
+  lazy val globalRunBeforeFile: Path = home.resolve(".scala-repl-pp.sc")
+  lazy val globalRunBeforeFileMaybe: Option[Path] = Option(globalRunBeforeFile).filter(Files.exists(_))
+  lazy val globalRunBeforeLines: Seq[String] = globalRunBeforeFileMaybe.map(linesFromFile).getOrElse(Seq.empty)
 
   private[replpp] def DefaultRunBeforeLines(using colors: Colors) = {
     val colorsImport = colors match {

From 2cee8fb333ac51940ea3fc2bcf6fa1d8a47f3a78 Mon Sep 17 00:00:00 2001
From: Michael Pollmeier <michael@michaelpollmeier.com>
Date: Mon, 18 Nov 2024 17:01:06 +0100
Subject: [PATCH 10/11] document global runBefore file

---
 README.md | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/README.md b/README.md
index c580fb27..3cb82fac 100644
--- a/README.md
+++ b/README.md
@@ -487,24 +487,16 @@ stringcalc> add(One, Two)
 val res0: stringcalc.Number = Number(3)
 ```
 
-## Global predef file: `~/.scala-repl-pp.sc`
-Code that should be available across all srp sessions can be written into your local `~/.scala-repl-pp.sc`. 
+## Global runBefore file: `~/.scala-repl-pp.sc`
+Code in this file will get executed at the start of each srp session, including scripts.
 
 ```
-echo 'def bar = 90' > ~/.scala-repl-pp.sc
-echo 'def baz = 91' > script1.sc
-echo 'def bam = 92' > script2.sc
+echo 'import Short.MaxValue' > ~/.scala-repl-pp.sc
 
-./srp --predef script1.sc --predef script2.sc
-
-scala> bar
-val res0: Int = 90
-
-scala> baz
-val res1: Int = 91
+./srp
 
-scala> bam
-val res2: Int = 92
+scala> MaxValue
+val res0: Int = 32767
 ```
 
 ## Verbose mode

From 20caf8a00d45654a7979bb9702b4095410042e99 Mon Sep 17 00:00:00 2001
From: Michael Pollmeier <michael@michaelpollmeier.com>
Date: Mon, 18 Nov 2024 18:31:00 +0100
Subject: [PATCH 11/11] readme

---
 README.md | 61 +++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 41 insertions(+), 20 deletions(-)

diff --git a/README.md b/README.md
index 3cb82fac..920e6386 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,6 @@ srp
 Prerequisite: jdk11+
 
 ## TOC
-<!-- markdown-toc --maxdepth 3 README.md|tail -n +4 -->
 - [Benefits over / comparison with](#benefits-over--comparison-with)
   * [Regular Scala REPL](#regular-scala-repl)
   * [Ammonite](#ammonite)
@@ -28,14 +27,15 @@ Prerequisite: jdk11+
 - [Prerequisite for all of the below: run `sbt stage` or download the latest release](#prerequisite-for-all-of-the-below-run-sbt-stage-or-download-the-latest-release)
 - [REPL](#repl)
   * [run with defaults](#run-with-defaults)
-  * [customize prompt, greeting and exit code](#customize-prompt-greeting-and-exit-code)
-  * [execute some predef code](#execute-some-predef-code)
+  * [execute code at the start with `--runBefore`](#execute-code-at-the-start-with---runbefore)
+  * [`--predef`: code that is compiled but not executed](#--predef-code-that-is-compiled-but-not-executed)
   * [Operators: Redirect to file, pipe to external command](#operators-redirect-to-file-pipe-to-external-command)
   * [Add dependencies with maven coordinates](#add-dependencies-with-maven-coordinates)
   * [Importing additional script files interactively](#importing-additional-script-files-interactively)
   * [Adding classpath entries](#adding-classpath-entries)
   * [Rendering of output](#rendering-of-output)
   * [Exiting the REPL](#exiting-the-repl)
+  * [customize prompt, greeting and exit code](#customize-prompt-greeting-and-exit-code)
   * [Looking up the current terminal width](#looking-up-the-current-terminal-width)
 - [Scripting](#scripting)
   * [Simple "Hello world" script](#simple-hello-world-script)
@@ -49,7 +49,6 @@ Prerequisite: jdk11+
   * [Attach a debugger (remote jvm debug)](#attach-a-debugger-remote-jvm-debug)
 - [Server mode](#server-mode)
 - [Embed into your own project](#embed-into-your-own-project)
-- [Global predef file: `~/.scala-repl-pp.sc`](#global-predef-file-scala-repl-ppsc)
 - [Verbose mode](#verbose-mode)
 - [Inherited classpath](#inherited-classpath)
 - [Parameters cheat sheet: the most important ones](#parameters-cheat-sheet-the-most-important-ones)
@@ -62,7 +61,8 @@ Prerequisite: jdk11+
   * [How can I get a new binary (bootstrapped) release?](#how-can-i-get-a-new-binary-bootstrapped-release)
   * [Updating the Scala version](#updating-the-scala-version)
   * [Updating the shaded libraries](#updating-the-shaded-libraries)
-- [Fineprint](#fineprint)  
+- [Fineprint](#fineprint)
+
 
 ## Benefits over / comparison with
 
@@ -100,10 +100,28 @@ scala-cli wraps and invokes the regular Scala REPL (by default; or optionally Am
 ./srp
 ```
 
-### customize prompt, greeting and exit code
-./srp --prompt myprompt --greeting 'hey there!' --onExitCode 'println("see ya!")'
+### execute code at the start with `--runBefore`
+```
+./srp --runBefore 'import Byte.MaxValue'
+
+scala> MaxValue
+val res0: Int = 127
+```
+
+You can specify this parameter multiple times, the given statements will be executed in the given order.
+
+If you want to execute some code _every single time_ you start a session, just write it to `~/.scala-repl-pp.sc`
+```
+echo 'import Short.MaxValue' > ~/.scala-repl-pp.sc
+
+./srp
+
+scala> MaxValue
+val res0: Int = 32767
+```
 
-### execute some predef code
+### `--predef`: add source files to the classpath
+Additional source files that are compiled added to the classpath, but unlike `runBefore` not executed straight away can be provided via `--predef`. 
 ```
 echo 'def foo = 42' > foo.sc
 
@@ -112,6 +130,12 @@ scala> foo
 val res0: Int = 42
 ```
 
+You can specify this parameter multiple times (`--predef one.sc --predef two.sc`).
+
+Why not use `runBefore` instead? For simple examples like the one above, you can do so. If it gets more complicated and you have multiple files referencing each others, `predef` allows you to treat it as one compilation unit, which isn't possible with `runBefore`. And as you add more code it's get's easier to manage in files rather than command line arguments. 
+
+Note that predef files may not contain toplevel statements like `println("foo")` - instead, these either belong into your main script (if you're executing one) and/or can be passed to the repl via `runBefore`.
+
 ### Operators: Redirect to file, pipe to external command
 Inspired by unix shell redirection and pipe operators (`>`, `>>` and `|`) you can redirect output into files with `#>` (overrides existing file) and `#>>` (create or append to file), and use `#|` to pipe the output to a command, such as `less`:
 ```scala
@@ -274,6 +298,15 @@ $
 ```
 Context: we'd prefer to cancel the long-running operation, but that's not so easy on the JVM.
 
+### customize prompt, greeting and exit code
+```
+./srp --prompt myprompt --greeting 'hey there!' --onExitCode 'println("see ya!")'
+
+hey there!
+myprompt> :exit
+see ya!
+```
+
 ### Looking up the current terminal width
 In case you want to adjust your output rendering to the available terminal size, you can look it up:
 
@@ -487,18 +520,6 @@ stringcalc> add(One, Two)
 val res0: stringcalc.Number = Number(3)
 ```
 
-## Global runBefore file: `~/.scala-repl-pp.sc`
-Code in this file will get executed at the start of each srp session, including scripts.
-
-```
-echo 'import Short.MaxValue' > ~/.scala-repl-pp.sc
-
-./srp
-
-scala> MaxValue
-val res0: Int = 32767
-```
-
 ## Verbose mode
 If verbose mode is enabled, you'll get additional information about classpaths and complete scripts etc. 
 To enable it, you can either pass `--verbose` or set the environment variable `SCALA_REPL_PP_VERBOSE=true`.