added -Xmacro-settings option and API with the same behaviour as in Scala2

 added @Experimenta annotation to new API method

 modified message, according to review

Update library/src/scala/quoted/Quotes.scala

Co-authored-by: Nicolas Stucki <[email protected]>

 settings -> XmacroSettings

 added CompilationInfo.XmacroSettings to MiMaFilters

 corrected MiMaFilters

 added examples from scala#12039 with workarround against scala#14245

Co-authored-by:  David Barri <[email protected]>

Author: rssh

compiler/src/dotty/tools/dotc/config/ScalaSettings.scala

@@ -234,6 +234,8 @@ private sealed trait XSettings:
     def isTruthy(using Context) = XmixinForceForwarders.value == "true"
     def isAtLeastJunit(using Context) = isTruthy || XmixinForceForwarders.value == "junit"
   }
+
+  val XmacroSettings: Setting[List[String]] = MultiStringSetting("-Xmacro-settings", "setting1,setting2,..settingN", "List of settings which exposed to the macros")
 end XSettings
 
 /** -Y "Forking" as in forked tongue or "Private" settings */

compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala

@@ -78,6 +78,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
 
     object CompilationInfo extends CompilationInfoModule:
       def isWhileTyping: Boolean = !ctx.isAfterTyper
+      def XmacroSettings: List[String] = ctx.settings.XmacroSettings.value
     end CompilationInfo
 
     extension (expr: Expr[Any])

compiler/test/dotty/tools/dotc/CompilationTests.scala

@@ -207,6 +207,8 @@ class CompilationTests {
       compileFile("tests/run-custom-args/defaults-serizaliable-no-forwarders.scala", defaultOptions and "-Xmixin-force-forwarders:false"),
       compileFilesInDir("tests/run-custom-args/erased", defaultOptions.and("-language:experimental.erasedDefinitions")),
       compileFilesInDir("tests/run-custom-args/fatal-warnings", defaultOptions.and("-Xfatal-warnings")),
+      compileDir("tests/run-custom-args/Xmacro-settings/simple", defaultOptions.and("-Xmacro-settings:one,two,three")),
+      compileDir("tests/run-custom-args/Xmacro-settings/compileTimeEnv", defaultOptions.and("-Xmacro-settings:a,b=1,c.b.a=x.y.z=1,myLogger.level=INFO")),
       compileFilesInDir("tests/run-deep-subtype", allowDeepSubtypes),
       compileFilesInDir("tests/run", defaultOptions.and("-Ysafe-init"))
     ).checkRuns()

library/src/scala/quoted/Quotes.scala

@@ -238,6 +238,15 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
        *  This will be true when the macro is used in a transparent inline.
        */
       def isWhileTyping: Boolean
+
+      /** Expose macro-specific settings as a list of strings.
+       *  Settings can be set from command line with help of -Xmacro-settings options.
+       *
+       *  These will be used to expand any transparent macros or any non-transparent macro that is forced to expand while expanding the transparent macro.
+       *  Non-transparent macros are not guaranteed to be expanded with the same set of settings.
+       */
+      @experimental
+      def XmacroSettings: List[String]
     }
 
 

project/MiMaFilters.scala

@@ -17,6 +17,8 @@ object MiMaFilters {
     ProblemFilters.exclude[MissingClassProblem]("scala.compiletime.ops.float$"),
     ProblemFilters.exclude[MissingClassProblem]("scala.compiletime.ops.long"),
     ProblemFilters.exclude[MissingClassProblem]("scala.compiletime.ops.long$"),
+    ProblemFilters.exclude[ReversedMissingMethodProblem]("scala.quoted.Quotes#reflectModule#CompilationInfoModule.XmacroSettings"),
+    ProblemFilters.exclude[DirectMissingMethodProblem]("scala.quoted.Quotes#reflectModule#CompilationInfoModule.XmacroSettings"),
 
     // Should have been added in 3.1.0
     // These are only allowed on imports and therefore should not be present in binaries emitted before

tests/run-custom-args/Xmacro-settings/compileTimeEnv.check

@@ -0,0 +1,6 @@
+I'm a info msg
+I'm a warn msg
+a = []
+b = [1]
+c.b.a = [x.y.z=1]
+wat is not defined

tests/run-custom-args/Xmacro-settings/compileTimeEnv/Logging.scala

@@ -0,0 +1,36 @@
+import scala.compiletime.*
+import scala.quoted.*
+
+
+object Logging {
+
+  // Just use your imagination for now :)
+  private inline val Trace = 0
+  private inline val Debug = 1
+  private inline val Info  = 2
+  private inline val Warn  = 3
+
+  private transparent inline def chosenThreshold: Int = ${
+     choosenTresholdImpl
+  }
+
+
+  private def choosenTresholdImpl(using Quotes):Expr[Int] =
+    import quotes.reflect.*
+    MacroEnv.getInMacro("myLogger.level") match
+        case Some("TRACE") => Expr(Trace)
+        case Some("DEBUG") => Expr(Debug)
+        case Some("INFO")  => Expr(Info)
+        case Some("WARN")  => Expr(Warn)
+        case Some(x)       => report.errorAndAbort("Unsupported logging level: " + x)
+        case None          => Expr(Trace)
+
+  private inline def log(inline lvl: Int, inline msg: String): Unit =
+    inline if lvl >= chosenThreshold then println(msg)
+
+  inline def trace(inline msg: String): Unit = log(Trace, msg)
+  inline def debug(inline msg: String): Unit = log(Debug, msg)
+  inline def info (inline msg: String): Unit = log(Info , msg)
+  inline def warn (inline msg: String): Unit = log(Warn , msg)
+}
+

tests/run-custom-args/Xmacro-settings/compileTimeEnv/MacroEnv.scala

@@ -0,0 +1,25 @@
+import scala.quoted.*
+
+object MacroEnv {
+
+ inline def get(inline key:String):Option[String] = ${
+    getImpl('key)
+ }
+
+ def getImpl(key:Expr[String])(using Quotes):Expr[Option[String]] = {
+    import quotes.reflect.*
+    val retval = getInMacro(key.valueOrAbort)
+    Expr(retval)
+ }
+
+ def getInMacro(key:String)(using Quotes):Option[String] = {
+    import quotes.reflect.*
+    val keyEq = key + "="
+    CompilationInfo.XmacroSettings.collectFirst{
+      case v if v == key => ""
+      case v if v.startsWith(keyEq) =>
+                  v.substring(keyEq.length)
+    }
+ }
+
+}

tests/run-custom-args/Xmacro-settings/compileTimeEnv/Test.scala

@@ -0,0 +1,30 @@
+import scala.compiletime.*
+
+object Test {
+  import Logging.*
+
+  def main(args: Array[String]): Unit = {
+     runLog()
+     runBasic()
+  }
+
+  def runLog(): Unit = {
+    trace("I'm a trace msg")
+    debug("I'm a debug msg")
+    info("I'm a info msg")
+    warn("I'm a warn msg")
+  }
+
+  def runBasic(): Unit = {
+    printEnv("a")    
+    printEnv("b")    
+    printEnv("c.b.a")    
+    printEnv("wat")    
+  }
+
+  inline def printEnv(inline k: String): Unit =
+    MacroEnv.get(k) match
+      case Some(v) => println(s"$k = [$v]")
+      case None    => println(k + " is not defined")
+
+}

tests/run-custom-args/Xmacro-settings/simple/M1.scala

@@ -0,0 +1,15 @@
+package x
+
+import scala.quoted.*
+
+object M:
+
+  inline def settingsContains(inline x:String): Boolean = ${
+     settingsContainsImpl('x)
+  }
+
+  def settingsContainsImpl(x:Expr[String])(using Quotes): Expr[Boolean] =
+     import quotes.reflect.*
+     val v = x.valueOrAbort
+     val r = CompilationInfo.XmacroSettings.contains(v)
+     Expr(r)

tests/run-custom-args/Xmacro-settings/simple/Test.scala

@@ -0,0 +1,10 @@
+import x.*
+
+object Test {
+
+   def main(args: Array[String]):Unit =
+    assert(M.settingsContains("one"))
+    assert(!M.settingsContains("notwo"))
+    assert(M.settingsContains("two"))
+
+}