Add support for passing Markdown code as snippets

modules/build/src/main/scala/scala/build/input/Inputs.scala

@@ -210,7 +210,8 @@ object Inputs {
   def validateSnippets(
     scriptSnippetList: List[String] = List.empty,
     scalaSnippetList: List[String] = List.empty,
-    javaSnippetList: List[String] = List.empty
+    javaSnippetList: List[String] = List.empty,
+    markdownSnippetList: List[String] = List.empty
   ): Seq[Either[String, Seq[Element]]] = {
     def validateSnippet(
       snippetList: List[String],
@@ -236,6 +237,15 @@ object Inputs {
         javaSnippetList,
         (content, snippetNameSuffix) =>
           VirtualJavaFile(content, s"<snippet>-java-$snippetNameSuffix")
+      ),
+      validateSnippet(
+        markdownSnippetList,
+        (content, snippetNameSuffix) =>
+          VirtualMarkdownFile(
+            content,
+            s"<snippet>-markdown-$snippetNameSuffix",
+            os.sub / s"$snippetNameSuffix.md"
+          )
       )
     ).flatten
   }
@@ -299,6 +309,7 @@ object Inputs {
     scriptSnippetList: List[String],
     scalaSnippetList: List[String],
     javaSnippetList: List[String],
+    markdownSnippetList: List[String],
     acceptFds: Boolean,
     forcedWorkspace: Option[os.Path],
     enableMarkdown: Boolean,
@@ -308,7 +319,7 @@ object Inputs {
     val validatedArgs: Seq[Either[String, Seq[Element]]] =
       validateArgs(args, cwd, download, stdinOpt, acceptFds, enableMarkdown)
     val validatedSnippets: Seq[Either[String, Seq[Element]]] =
-      validateSnippets(scriptSnippetList, scalaSnippetList, javaSnippetList)
+      validateSnippets(scriptSnippetList, scalaSnippetList, javaSnippetList, markdownSnippetList)
     val validatedArgsAndSnippets = validatedArgs ++ validatedSnippets
     val invalid = validatedArgsAndSnippets.collect {
       case Left(msg) => msg
@@ -342,14 +353,16 @@ object Inputs {
     scriptSnippetList: List[String] = List.empty,
     scalaSnippetList: List[String] = List.empty,
     javaSnippetList: List[String] = List.empty,
+    markdownSnippetList: List[String] = List.empty,
     acceptFds: Boolean = false,
     forcedWorkspace: Option[os.Path] = None,
     enableMarkdown: Boolean = false,
     allowRestrictedFeatures: Boolean,
     extraClasspathWasPassed: Boolean
   ): Either[BuildException, Inputs] =
     if (
-      args.isEmpty && scriptSnippetList.isEmpty && scalaSnippetList.isEmpty && javaSnippetList.isEmpty && !extraClasspathWasPassed
+      args.isEmpty && scriptSnippetList.isEmpty && scalaSnippetList.isEmpty && javaSnippetList.isEmpty &&
+      markdownSnippetList.isEmpty && !extraClasspathWasPassed
     )
       defaultInputs().toRight(new InputsException(
         "No inputs provided (expected files with .scala, .sc, .java or .md extensions, and / or directories)."
@@ -364,6 +377,7 @@ object Inputs {
         scriptSnippetList,
         scalaSnippetList,
         javaSnippetList,
+        markdownSnippetList,
         acceptFds,
         forcedWorkspace,
         enableMarkdown,

modules/cli-options/src/main/scala/scala/cli/commands/SnippetOptions.scala

@@ -32,6 +32,17 @@ final case class SnippetOptions(
    @Group("Java")
   @HelpMessage("A synonym to --scala-snippet, which defaults the sub-command to `run` when no sub-command is passed explicitly")
     executeJava: List[String] = List.empty,
+
+  @Group("Markdown")
+  @HelpMessage("[experimental] Allows to execute a passed string as Markdown code")
+  @Name("mdSnippet")
+    markdownSnippet: List[String] = List.empty,
+
+  @Group("Markdown")
+  @HelpMessage("[experimental] A synonym to --markdown-snippet, which defaults the sub-command to `run` when no sub-command is passed explicitly")
+  @Name("executeMd")
+  @Hidden
+    executeMarkdown: List[String] = List.empty,
 )
 // format: on
 

modules/cli/src/main/scala/scala/cli/commands/default/Default.scala

@@ -40,6 +40,7 @@ class Default(
         val shouldDefaultToRun =
           args.remaining.nonEmpty || options.shared.snippet.executeScript.nonEmpty ||
           options.shared.snippet.executeScala.nonEmpty || options.shared.snippet.executeJava.nonEmpty ||
+          options.shared.snippet.executeMarkdown.nonEmpty ||
           (options.shared.extraJarsAndClassPath.nonEmpty && options.sharedRun.mainClass.mainClass.nonEmpty)
         if shouldDefaultToRun then RunOptions.parser else ReplOptions.parser
       }.parse(rawArgs) match

modules/cli/src/main/scala/scala/cli/commands/publish/PublishSetup.scala

@@ -56,6 +56,7 @@ object PublishSetup extends ScalaCommand[PublishSetupOptions] {
         options.input.forbid,
         Nil,
         Nil,
+        Nil,
         Nil
       )
       maybeInputs match {

modules/cli/src/main/scala/scala/cli/commands/util/SharedOptionsUtil.scala

@@ -60,6 +60,7 @@ object SharedOptionsUtil extends CommandHelpers {
     scriptSnippetList: List[String],
     scalaSnippetList: List[String],
     javaSnippetList: List[String],
+    markdownSnippetList: List[String],
     enableMarkdown: Boolean = false,
     extraClasspathWasPassed: Boolean = false
   ): Either[BuildException, Inputs] = {
@@ -80,6 +81,7 @@ object SharedOptionsUtil extends CommandHelpers {
       scriptSnippetList = scriptSnippetList,
       scalaSnippetList = scalaSnippetList,
       javaSnippetList = javaSnippetList,
+      markdownSnippetList = markdownSnippetList,
       acceptFds = !Properties.isWin,
       forcedWorkspace = forcedWorkspaceOpt,
       enableMarkdown = enableMarkdown,
@@ -407,13 +409,15 @@ object SharedOptionsUtil extends CommandHelpers {
         scriptSnippetList = allScriptSnippets,
         scalaSnippetList = allScalaSnippets,
         javaSnippetList = allJavaSnippets,
+        markdownSnippetList = allMarkdownSnippets,
         enableMarkdown = v.markdown.enableMarkdown,
         extraClasspathWasPassed = v.extraJarsAndClassPath.nonEmpty
       )
 
-    def allScriptSnippets: List[String] = v.snippet.scriptSnippet ++ v.snippet.executeScript
-    def allScalaSnippets: List[String]  = v.snippet.scalaSnippet ++ v.snippet.executeScala
-    def allJavaSnippets: List[String]   = v.snippet.javaSnippet ++ v.snippet.executeJava
+    def allScriptSnippets: List[String]   = v.snippet.scriptSnippet ++ v.snippet.executeScript
+    def allScalaSnippets: List[String]    = v.snippet.scalaSnippet ++ v.snippet.executeScala
+    def allJavaSnippets: List[String]     = v.snippet.javaSnippet ++ v.snippet.executeJava
+    def allMarkdownSnippets: List[String] = v.snippet.markdownSnippet ++ v.snippet.executeMarkdown
 
     def validateInputArgs(args: Seq[String]): Seq[Either[String, Seq[Element]]] =
       Inputs.validateArgs(

modules/integration/src/test/scala/scala/cli/integration/DefaultTests.scala

@@ -77,6 +77,26 @@ class DefaultTests extends ScalaCliSuite {
     }
   }
 
+  test("default to the run sub-command when a md snippet is passed with --execute-markdown") {
+    TestInputs.empty.fromRoot { root =>
+      val msg       = "Hello world"
+      val quotation = TestUtil.argQuotationMark
+      val res =
+        os.proc(
+          TestUtil.cli,
+          "--execute-markdown",
+          s"""# A Markdown snippet
+             |With some scala code
+             |```scala
+             |println($quotation$msg$quotation)
+             |```""".stripMargin,
+          TestUtil.extraOptions
+        )
+          .call(cwd = root)
+      expect(res.out.trim() == msg)
+    }
+  }
+
   test("running scala-cli with a script snippet passed with -e shouldn't allow repl-only options") {
     TestInputs.empty.fromRoot { root =>
       val replSpecificOption = "--repl-dry-run"

modules/integration/src/test/scala/scala/cli/integration/RunSnippetTestDefinitions.scala

@@ -53,6 +53,27 @@ trait RunSnippetTestDefinitions { _: RunTestDefinitions =>
     }
   }
 
+  test("correctly run a markdown snippet") {
+    emptyInputs.fromRoot { root =>
+      val msg       = "Hello world"
+      val quotation = TestUtil.argQuotationMark
+      val res =
+        os.proc(
+          TestUtil.cli,
+          "run",
+          "--markdown-snippet",
+          s"""# A Markdown snippet
+             |With some scala code
+             |```scala
+             |println($quotation$msg$quotation)
+             |```""".stripMargin,
+          extraOptions
+        )
+          .call(cwd = root)
+      expect(res.out.trim() == msg)
+    }
+  }
+
   test("correctly run multiple snippets") {
     emptyInputs.fromRoot { root =>
       val quotation = TestUtil.argQuotationMark

website/docs/guides/snippets.md

@@ -80,6 +80,24 @@ Hello
 
 </ChainedSnippets>
 
+- Markdown code (experimental)
+
+<ChainedSnippets>
+
+````bash
+scala-cli run --markdown-snippet '# Markdown snippet
+with a code block
+```scala
+println("Hello")
+```'
+````
+
+```text
+Hello
+```
+
+</ChainedSnippets>
+
 - a mix of Scala, Java and scripts
 
 <ChainedSnippets>

website/docs/reference/cli-options.md

@@ -1399,6 +1399,19 @@ Allows to execute a passed string as Java code
 
 A synonym to --scala-snippet, which defaults the sub-command to `run` when no sub-command is passed explicitly
 
+### `--markdown-snippet`
+
+Aliases: `--md-snippet`
+
+[experimental] Allows to execute a passed string as Markdown code
+
+### `--execute-markdown`
+
+Aliases: `--execute-md`
+
+[Internal]
+[experimental] A synonym to --markdown-snippet, which defaults the sub-command to `run` when no sub-command is passed explicitly
+
 ## Test options
 
 Available in commands: