Fix - ignore shebang lines only at the top of source files (#129)

* Fix - ignore shebang lines only at the top of source files

* Fix parsing new lines for windows

Author: lwronski

modules/build/src/main/scala/scala/build/preprocessing/ScriptPreprocessor.scala

@@ -49,11 +49,19 @@ final case class ScriptPreprocessor(codeWrapper: CodeWrapper) extends Preprocess
 
 object ScriptPreprocessor {
 
-  private val sheBangRegex: Regex = s"""((#!.*)|(!#.*))""".r
+  private val sheBangRegex: Regex = s"""(^(#!.*(\\r\\n?|\\n)?)+(\\s*!#.*)?)""".r
 
   private def ignoreSheBangLines(content: String): String = {
     if (content.startsWith("#!")) {
-      sheBangRegex.replaceAllIn(content, "")
+      val regexMatch = sheBangRegex.findFirstMatchIn(content)
+      regexMatch match {
+        case Some(firstMatch) =>
+          content.replace(
+            firstMatch.toString(),
+            System.lineSeparator() * firstMatch.toString().split(System.lineSeparator()).length
+          )
+        case None => content
+      }
     }
     else {
       content

modules/build/src/test/scala/scala/build/tests/SourcesTests.scala

@@ -109,27 +109,27 @@ class SourcesTests extends munit.FunSuite {
       os.rel / "something1.sc" ->
         """#!/usr/bin/env scala-cli
           |
-          |println("Hello World")
-          |""".stripMargin,
+          |println("Hello World")""".stripMargin,
       os.rel / "something2.sc" ->
         """#!/usr/bin/scala-cli
           |
-          |println("Hello World")
-          |""".stripMargin,
+          |println("Hello World")""".stripMargin,
       os.rel / "something3.sc" ->
         """#!/usr/bin/scala-cli
           |#! nix-shell -i scala-cli
           |
-          |println("Hello World")
-          |""".stripMargin,
+          |println("Hello World")""".stripMargin,
       os.rel / "something4.sc" ->
         """#!/usr/bin/scala-cli
           |#! nix-shell -i scala-cli
           |
           |!#
           |
-          |println("Hello World")
-          |""".stripMargin
+          |println("Hello World")""".stripMargin,
+      os.rel / "something5.sc" ->
+        """#!/usr/bin/scala-cli
+          |
+          |println("Hello World #!")""".stripMargin
     )
     val expectedParsedCodes = Seq(
       """
@@ -144,7 +144,10 @@ class SourcesTests extends munit.FunSuite {
         |
         |
         |
-        |println("Hello World")""".stripMargin
+        |println("Hello World")""".stripMargin,
+      """
+        |
+        |println("Hello World #!")""".stripMargin
     )
 
     testInputs.withInputs { (_, inputs) =>

website/docs/input.md

@@ -169,6 +169,22 @@ scala-cli my-app --main-class main
 Note that we pass an explicit main class. Both scripts automatically get a main class, so this
 is required to disambiguate them.
 
+### Self executable Scala Script
+
+You can define file with shebang header to self executable. It could be also run as a normal script.
+
+```bash
+cat HelloScript.sc
+# #!/usr/bin/env scala-cli
+# println("Hello world")
+
+scala-cli run HelloScript.sc
+# Hello world
+chmod +x HelloScript.sc
+./HelloScript.sc
+# Hello world
+```
+
 ### Difference with Ammonite scripts
 
 [Ammonite](http://ammonite.io) is a popular REPL for Scala, that is also able to compile and run

website/docs/run.md

@@ -64,6 +64,19 @@ and that Scala Native only supports Linux and macOS for now.
 scala-cli my-scala-native-app/ --native
 ```
 
+## Scala Scripts
+
+Scala CLI can also compile and run Scala scripts.
+```bash
+cat HelloScript.sc
+# #!/usr/bin/env scala-cli
+
+# println("Hello world from scala script")
+
+scala-cli run HelloScript.sc
+# Hello world from scala script
+```
+
 ## ScalaCli from docker
 
 Scala applications can also be compiled and run using docker image with `scala-cli`.