Merge pull request #5575 from dotty-staging/add-macro-interpolation-core

Allow macros calling inherited methods on modules

Author: nicolasstucki

compiler/src/dotty/tools/dotc/transform/Splicer.scala

@@ -112,8 +112,8 @@ object Splicer {
       }
     }
 
-    protected def interpretStaticMethodCall(fn: Symbol, args: => List[Object])(implicit env: Env): Object = {
-      val instance = loadModule(fn.owner)
+    protected def interpretStaticMethodCall(moduleClass: Symbol, fn: Symbol, args: => List[Object])(implicit env: Env): Object = {
+      val instance = loadModule(moduleClass)
       def getDirectName(tp: Type, name: TermName): TermName = tp.widenDealias match {
         case tp: AppliedType if defn.isImplicitFunctionType(tp) =>
           getDirectName(tp.args.last, NameKinds.DirectMethodName(name))
@@ -270,7 +270,7 @@ object Splicer {
     protected def interpretVarargs(args: List[Boolean])(implicit env: Env): Boolean = args.forall(identity)
     protected def interpretTastyContext()(implicit env: Env): Boolean = true
     protected def interpretQuoteContext()(implicit env: Env): Boolean = true
-    protected def interpretStaticMethodCall(fn: Symbol, args: => List[Boolean])(implicit env: Env): Boolean = args.forall(identity)
+    protected def interpretStaticMethodCall(module: Symbol, fn: Symbol, args: => List[Boolean])(implicit env: Env): Boolean = args.forall(identity)
     protected def interpretModuleAccess(fn: Symbol)(implicit env: Env): Boolean = true
     protected def interpretNew(fn: Symbol, args: => List[Boolean])(implicit env: Env): Boolean = args.forall(identity)
 
@@ -292,7 +292,7 @@ object Splicer {
     protected def interpretLiteral(value: Any)(implicit env: Env): Result
     protected def interpretVarargs(args: List[Result])(implicit env: Env): Result
     protected def interpretTastyContext()(implicit env: Env): Result
-    protected def interpretStaticMethodCall(fn: Symbol, args: => List[Result])(implicit env: Env): Result
+    protected def interpretStaticMethodCall(module: Symbol, fn: Symbol, args: => List[Result])(implicit env: Env): Result
     protected def interpretModuleAccess(fn: Symbol)(implicit env: Env): Result
     protected def interpretNew(fn: Symbol, args: => List[Result])(implicit env: Env): Result
     protected def unexpectedTree(tree: Tree)(implicit env: Env): Result
@@ -313,9 +313,14 @@ object Splicer {
       case Call(fn, args) =>
         if (fn.symbol.isConstructor && fn.symbol.owner.owner.is(Package)) {
           interpretNew(fn.symbol, args.map(interpretTree))
+        } else if (fn.symbol.is(Module)) {
+          interpretModuleAccess(fn.symbol)
         } else if (fn.symbol.isStatic) {
-          if (fn.symbol.is(Module)) interpretModuleAccess(fn.symbol)
-          else interpretStaticMethodCall(fn.symbol, args.map(arg => interpretTree(arg)))
+          val module = fn.symbol.owner
+          interpretStaticMethodCall(module, fn.symbol, args.map(arg => interpretTree(arg)))
+        } else if (fn.qualifier.symbol.is(Module) && fn.qualifier.symbol.isStatic) {
+          val module = fn.qualifier.symbol.moduleClass
+          interpretStaticMethodCall(module, fn.symbol, args.map(arg => interpretTree(arg)))
         } else if (env.contains(fn.name)) {
           env(fn.name)
         } else {

tests/run/tasty-interpolation-1.check

@@ -0,0 +1,3 @@
+Hello world!
+Hello world!\n
+Hello foo!

tests/run/tasty-interpolation-1/Macro.scala

@@ -0,0 +1,95 @@
+
+import scala.quoted._
+import scala.tasty.Reflection
+import scala.language.implicitConversions
+import scala.quoted.Exprs.LiftedExpr
+import scala.quoted.Toolbox.Default._
+
+object Macro {
+
+  class StringContextOps(strCtx: => StringContext) {
+    inline def s2(args: Any*): String = ~SIntepolator('(strCtx), '(args))
+    inline def raw2(args: Any*): String = ~RawIntepolator('(strCtx), '(args))
+    inline def foo(args: Any*): String = ~FooIntepolator('(strCtx), '(args))
+  }
+  implicit inline def SCOps(strCtx: => StringContext): StringContextOps = new StringContextOps(strCtx)
+}
+
+object SIntepolator extends MacroStringInterpolator[String] {
+  protected def interpolate(strCtx: StringContext, args: List[Expr[Any]])(implicit reflect: Reflection): Expr[String] =
+    '((~strCtx.toExpr).s(~args.toExprOfList: _*))
+}
+
+object RawIntepolator extends MacroStringInterpolator[String] {
+  protected def interpolate(strCtx: StringContext, args: List[Expr[Any]])(implicit reflect: Reflection): Expr[String] =
+    '((~strCtx.toExpr).raw(~args.toExprOfList: _*))
+}
+
+object FooIntepolator extends MacroStringInterpolator[String] {
+  protected def interpolate(strCtx: StringContext, args: List[Expr[Any]])(implicit reflect: Reflection): Expr[String] =
+    '((~strCtx.toExpr).s(~args.map(_ => '("foo")).toExprOfList: _*))
+}
+
+// TODO put this class in the stdlib or separate project?
+abstract class MacroStringInterpolator[T] {
+
+  final def apply(strCtxExpr: Expr[StringContext], argsExpr: Expr[Seq[Any]])(implicit reflect: Reflection): Expr[T] = {
+    try interpolate(strCtxExpr, argsExpr)
+    catch {
+      case ex: NotStaticlyKnownError =>
+        // TODO use ex.expr to recover the position
+        throw new QuoteError(ex.getMessage)
+      case ex: StringContextError =>
+        // TODO use ex.idx to recover the position
+        throw new QuoteError(ex.getMessage)
+      case ex: ArgumentError =>
+        // TODO use ex.idx to recover the position
+        throw new QuoteError(ex.getMessage)
+    }
+  }
+
+  protected def interpolate(strCtxExpr: Expr[StringContext], argsExpr: Expr[Seq[Any]])(implicit reflect: Reflection): Expr[T] =
+    interpolate(getStaticStringContext(strCtxExpr), getArgsList(argsExpr))
+
+  protected def interpolate(strCtx: StringContext, argExprs: List[Expr[Any]])(implicit reflect: Reflection): Expr[T]
+
+  protected def getStaticStringContext(strCtxExpr: Expr[StringContext])(implicit reflect: Reflection): StringContext = {
+    import reflect._
+    strCtxExpr.unseal.underlyingArgument match {
+      case Term.Select(Term.Typed(Term.Apply(_, List(Term.Apply(_, List(Term.Typed(Term.Repeated(strCtxArgTrees), TypeTree.Inferred()))))), _), _) =>
+        val strCtxArgs = strCtxArgTrees.map {
+          case Term.Literal(Constant.String(str)) => str
+          case tree => throw new NotStaticlyKnownError("Expected statically known StringContext", tree.seal[Any])
+        }
+        StringContext(strCtxArgs: _*)
+      case tree =>
+        throw new NotStaticlyKnownError("Expected statically known StringContext", tree.seal[Any])
+    }
+  }
+
+  protected def getArgsList(argsExpr: Expr[Seq[Any]])(implicit reflect: Reflection): List[Expr[Any]] = {
+    import reflect._
+    argsExpr.unseal.underlyingArgument match {
+      case Term.Typed(Term.Repeated(args), _) => args.map(_.seal[Any])
+      case tree => throw new NotStaticlyKnownError("Expected statically known argument list", tree.seal[Any])
+    }
+  }
+
+  protected implicit def StringContextIsLiftable: Liftable[StringContext] = new Liftable[StringContext] {
+    def toExpr(strCtx: StringContext): Expr[StringContext] = {
+      // TODO define in stdlib?
+      implicit def ListIsLiftable: Liftable[List[String]] = new Liftable[List[String]] {
+        override def toExpr(list: List[String]): Expr[List[String]] = list match {
+          case x :: xs => '(~x.toExpr :: ~toExpr(xs))
+          case Nil => '(Nil)
+        }
+      }
+      '(StringContext(~strCtx.parts.toList.toExpr: _*))
+    }
+  }
+
+  protected class NotStaticlyKnownError(msg: String, expr: Expr[Any]) extends Exception(msg)
+  protected class StringContextError(msg: String, idx: Int, start: Int = -1, end: Int = -1) extends Exception(msg)
+  protected class ArgumentError(msg: String, idx: Int) extends Exception(msg)
+
+}

tests/run/tasty-interpolation-1/Test_2.scala

@@ -0,0 +1,10 @@
+import Macro._
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val w = "world"
+    println(s2"Hello $w!")
+    println(raw2"Hello $w!\n")
+    println(foo"Hello $w!")
+  }
+}