Scaladoc: Allow to set a comment syntax based on path to source

project/Build.scala

@@ -1801,6 +1801,10 @@ object ScaladocConfigs {
       .add(Revision("main"))
       .add(SnippetCompiler(List("scaladoc-testcases/docs=compile")))
       .add(SiteRoot("scaladoc-testcases/docs"))
+      .add(CommentSyntax(List(
+        "scaladoc-testcases/src/example/comment-md=markdown",
+        "scaladoc-testcases/src/example/comment-wiki=wiki"
+      )))
       .add(ExternalMappings(List(dottyExternalMapping, javaExternalMapping)))
       .withTargets(tastyRoots)
   }
@@ -1830,7 +1834,10 @@ object ScaladocConfigs {
       .add(Revision("main"))
       .add(ExternalMappings(List(javaExternalMapping)))
       .add(DocRootContent(docRootFile.toString))
-      .add(CommentSyntax("wiki"))
+      .add(CommentSyntax(List(
+        s"${dottyLibRoot}=markdown",
+        s"${stdLibRoot}=wiki"
+      )))
       .add(VersionsDictionaryUrl("https://scala-lang.org/api/versions.json"))
       .add(DocumentSyntheticTypes(true))
       .add(SnippetCompiler(List(

project/ScaladocGeneration.scala

@@ -45,7 +45,7 @@ object ScaladocGeneration {
     def key: String = "-source-links"
   }
 
-  case class CommentSyntax(value: String) extends Arg[String] {
+  case class CommentSyntax(value: List[String]) extends Arg[List[String]] {
     def key: String = "-comment-syntax"
   }
 

project/scripts/cmdScaladocTests

@@ -35,6 +35,7 @@ dist/target/pack/bin/scaladoc \
   "-skip-by-id:scala.runtime.stdLibPatches" \
   "-skip-by-id:scala.runtime.MatchCase" \
   "-snippet-compiler:scaladoc-testcases/docs=compile" \
+  "-comment-syntax:scaladoc-testcases/src/example/comment-md=markdown,scaladoc-testcases/src/example/comment-wiki=wiki" \
   -siteroot scaladoc-testcases/docs \
   -project-footer "Copyright (c) 2002-2022, LAMP/EPFL" \
   -default-template static-site-main \

scaladoc-testcases/src/example/comment-md/CommentExample.scala

@@ -0,0 +1,6 @@
+package example.comment.md
+/**
+ * # markdown header
+ * Markdown syntax is used here.
+ */
+object CommentExample

scaladoc-testcases/src/example/comment-wiki/CommentExample.scala

@@ -0,0 +1,6 @@
+package example.comment.wiki
+/**
+ * = wiki header =
+ * Wiki syntax is used here.
+ */
+object CommentExample

scaladoc/src/dotty/tools/scaladoc/DocContext.scala

@@ -74,6 +74,8 @@ case class NavigationNode(name: String, dri: DRI, nested: Seq[NavigationNode])
 case class DocContext(args: Scaladoc.Args, compilerContext: CompilerContext):
   lazy val sourceLinks = SourceLinks.load(args.sourceLinks, args.revision)(using compilerContext)
 
+  lazy val commentSyntaxArgs = tasty.comments.CommentSyntaxArgs.load(args.defaultSyntax)(using compilerContext)
+
   lazy val snippetCompilerArgs = snippets.SnippetCompilerArgs.load(args.snippetCompiler)(using compilerContext)
 
   lazy val snippetChecker = snippets.SnippetChecker(args)(using compilerContext)

scaladoc/src/dotty/tools/scaladoc/Scaladoc.scala

@@ -18,18 +18,6 @@ import dotty.tools.scaladoc.Inkuire
 import dotty.tools.scaladoc.Inkuire._
 
 object Scaladoc:
-  enum CommentSyntax:
-    case Wiki
-    case Markdown
-
-  object CommentSyntax:
-    def parse(str: String) = str match
-        case "wiki" => Some(CommentSyntax.Wiki)
-        case "markdown" => Some(CommentSyntax.Markdown)
-        case _ => None
-
-    val default = CommentSyntax.Markdown
-
   case class Args(
     name: String,
     tastyDirs: Seq[File] = Nil,
@@ -41,7 +29,7 @@ object Scaladoc:
     projectVersion: Option[String] = None,
     projectLogo: Option[String] = None,
     projectFooter: Option[String] = None,
-    defaultSyntax: CommentSyntax = CommentSyntax.Markdown,
+    defaultSyntax: List[String] = Nil,
     sourceLinks: List[String] = Nil,
     revision: Option[String] = None,
     externalMappings: List[ExternalDocLink] = Nil,
@@ -164,12 +152,6 @@ object Scaladoc:
         report.warning("Destination is not provided, please provide '-d' parameter pointing to directory where docs should be created")
         File("output")
 
-      val parseSyntax: CommentSyntax = syntax.nonDefault.fold(CommentSyntax.default){ str =>
-        CommentSyntax.parse(str).getOrElse{
-          report.error(s"unrecognized value for -syntax option: $str")
-          CommentSyntax.default
-        }
-      }
       val legacySourceLinkList = if legacySourceLink.get.nonEmpty then List(legacySourceLink.get) else Nil
 
       val externalMappings =
@@ -219,7 +201,7 @@ object Scaladoc:
         projectVersion.nonDefault,
         projectLogo.nonDefault,
         projectFooter.nonDefault,
-        parseSyntax,
+        syntax.get,
         sourceLinks.get ++ legacySourceLinkList,
         revision.nonDefault,
         externalMappings ++ legacyExternalMappings,

scaladoc/src/dotty/tools/scaladoc/ScaladocSettings.scala

@@ -40,8 +40,8 @@ class ScaladocSettings extends SettingGroup with AllScalaSettings:
   val legacySourceLink: Setting[String] =
     StringSetting("-doc-source-url", "sources", "Legacy option from Scala 2. Use -source-links instead.", "")
 
-  val syntax: Setting[String] =
-    StringSetting("-comment-syntax", "syntax", "Syntax of the comment used", "")
+  val syntax: Setting[List[String]] =
+    MultiStringSetting("-comment-syntax", "syntax", tasty.comments.CommentSyntaxArgs.usage)
 
   val revision: Setting[String] =
     StringSetting("-revision", "revision", "Revision (branch or ref) used to build project project", "")

scaladoc/src/dotty/tools/scaladoc/tasty/ScalaDocSupport.scala

@@ -3,8 +3,8 @@ package tasty
 
 import scala.jdk.CollectionConverters._
 
-import dotty.tools.scaladoc.Scaladoc.CommentSyntax
-import dotty.tools.scaladoc.tasty.comments.Comment
+import dotty.tools.scaladoc.tasty.comments.{Comment, CommentSyntax}
+import dotty.tools.scaladoc.tasty.SymOps.source
 
 import scala.quoted._
 
@@ -14,17 +14,23 @@ object ScaladocSupport:
     import reflect.report
     val preparsed = comments.Preparser.preparse(comments.Cleaner.clean(comment))
 
+    def pathBasedCommentSyntax(): CommentSyntax =
+      val path = sym.source.map(_.path)
+      summon[DocContext].commentSyntaxArgs.get(path)
+
     val commentSyntax =
       preparsed.syntax.headOption match {
         case Some(commentSetting) =>
-          CommentSyntax.parse(commentSetting).getOrElse {
-            val msg = s"not a valid comment syntax: $commentSetting, defaulting to Markdown syntax."
+          CommentSyntax.CommentSyntaxParser.parse(commentSetting).getOrElse {
+            val defaultSyntax = pathBasedCommentSyntax()
+            val msg = s"not a valid comment syntax: $commentSetting, defaulting to ${defaultSyntax} syntax."
             // we should update pos with span from documentation
             pos.fold(report.warning(msg))(report.warning(msg, _))
 
-            CommentSyntax.default
+            defaultSyntax
           }
-        case None => summon[DocContext].args.defaultSyntax
+        case None => 
+          pathBasedCommentSyntax()
       }
 
     val parser = commentSyntax match {

scaladoc/src/dotty/tools/scaladoc/tasty/comments/CommentSyntaxArgs.scala

@@ -0,0 +1,55 @@
+package dotty.tools.scaladoc
+package tasty.comments
+
+import java.nio.file.Path
+
+enum CommentSyntax:
+  case Wiki
+  case Markdown
+
+object CommentSyntax:
+  object CommentSyntaxParser extends ArgParser[CommentSyntax]:
+    def parse(s: String): Either[String, CommentSyntax] = s match
+        case "wiki" => Right(CommentSyntax.Wiki)
+        case "markdown" => Right(CommentSyntax.Markdown)
+        case _ => Left(s"No such syntax found.")
+
+  val default = CommentSyntax.Markdown
+
+case class CommentSyntaxArgs(csFormats: PathBased[CommentSyntax]):
+  def get(path: Option[Path]): CommentSyntax =
+    path
+      .flatMap(p => csFormats.get(p).map(_.elem))
+      .getOrElse(CommentSyntax.default)
+
+object CommentSyntaxArgs:
+  val usage =
+    """
+    |Comment Syntax arguments provide a way to set comment syntax for specified paths.
+    |
+    |This setting accepts list of arguments in format:
+    |args := arg{,arg}
+    |arg := [path=]syntax
+    |where `path` is a prefix of the path to source files that will have a specific comment syntax set and `syntax` specifies the one used.
+    |
+    |If the path is not present, the argument will be used as the default for all unmatched paths.
+    |
+    |Available syntaxes:
+    |markdown
+    |wiki
+    |
+    """.stripMargin
+
+  def load(args: List[String])(using CompilerContext): CommentSyntaxArgs = {
+    PathBased.parse[CommentSyntax](args)(using CommentSyntax.CommentSyntaxParser) match {
+      case PathBased.ParsingResult(errors, res) =>
+        if errors.nonEmpty then report.warning(s"""
+            |Got following errors during comment syntax args parsing:
+            |$errors
+            |
+            |$usage
+            |""".stripMargin
+        )
+        CommentSyntaxArgs(res)
+    }
+  }