Added patch to allow definition of native metho...

Added patch to allow definition of native methods in Scala (contribution
from Stepan Koltsov)

8 files changed, 54 insertions, 8 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala b/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala
index fd396acd37..09935b69e6 100644
--- a/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala
+++ b/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala
@@ -109,8 +109,10 @@ abstract class GenICode extends SubComponent  {
 
         var ctx1 = ctx.enterMethod(m, tree.asInstanceOf[DefDef])
         addMethodParams(ctx1, vparamss)
+        val NativeAttr = atPhase(currentRun.typerPhase)(definitions.getClass("scala.native").tpe)
+        m.native = m.symbol.hasAttribute(NativeAttr)
 
-        if (!m.isDeferred) {
+        if (!m.isDeferred && !m.native) {
           ctx1 = genLoad(rhs, ctx1, m.returnType);
 
           // reverse the order of the local variables, to match the source-order
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
index bc8f4b1dd9..0203d73f39 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
@@ -404,6 +404,10 @@ abstract class GenJVM extends SubComponent {
       if (jclass.isInterface())
         flags = flags | JAccessFlags.ACC_ABSTRACT;
 
+      // native methods of objects are generated in mirror classes
+      if (method.native)
+        flags = flags | JAccessFlags.ACC_NATIVE
+
       jmethod = jclass.addNewMethod(flags,
                                     javaName(m.symbol),
                                     resTpe,
@@ -421,7 +425,7 @@ abstract class GenJVM extends SubComponent {
           m.symbol.attributes = ainfo :: m.symbol.attributes;
         }
 
-      if (!jmethod.isAbstract()) {
+      if (!jmethod.isAbstract() && !method.native) {
         jcode = jmethod.getCode().asInstanceOf[JExtendedCode]
 
         // add a fake local for debugging purpuses
diff --git a/src/compiler/scala/tools/nsc/symtab/Definitions.scala b/src/compiler/scala/tools/nsc/symtab/Definitions.scala
index a4a3b0ce79..566568b16a 100644
--- a/src/compiler/scala/tools/nsc/symtab/Definitions.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Definitions.scala
@@ -99,6 +99,7 @@ trait Definitions {
     var PredefModule: Symbol = _
       def Predef_classOf = getMember(PredefModule, nme.classOf)
       def Predef_identity = getMember(PredefModule, nme.identity)
+      def Predef_error    = getMember(PredefModule, nme.error)
     var ConsoleModule: Symbol = _
     var MatchErrorClass: Symbol = _
     //var MatchErrorModule: Symbol = _
@@ -369,6 +370,7 @@ trait Definitions {
     var DeprecatedAttr: Symbol = _
     var BeanPropertyAttr: Symbol = _
     var AnnotationDefaultAttr: Symbol = _
+    var NativeAttr: Symbol = _
 
     def getModule(fullname: Name): Symbol = getModuleOrClass(fullname, true)
 
@@ -937,6 +939,7 @@ trait Definitions {
       SerializableAttr = getClass("scala.serializable")
       BeanPropertyAttr = if (forCLDC || forMSIL) null else getClass("scala.reflect.BeanProperty")
       DeprecatedAttr = getClass("scala.deprecated")
+      NativeAttr     = getClass("scala.native")
 
       SyntheticClasses = new HashSet[Symbol]
       SyntheticClasses ++= List(
diff --git a/src/compiler/scala/tools/nsc/symtab/StdNames.scala b/src/compiler/scala/tools/nsc/symtab/StdNames.scala
index 12fbe8cf80..60caa722a8 100644
--- a/src/compiler/scala/tools/nsc/symtab/StdNames.scala
+++ b/src/compiler/scala/tools/nsc/symtab/StdNames.scala
@@ -259,6 +259,7 @@ trait StdNames {
     val equals_ = newTermName("equals")
     val _equals = newTermName("_equals")
     val _equalsWithVarArgs = newTermName("_equalsWithVarArgs")
+    val error = newTermName("error")
     val ex = newTermName("ex")
     val fail = newTermName("fail")
     val false_ = newTermName("false")
diff --git a/src/compiler/scala/tools/nsc/symtab/Symbols.scala b/src/compiler/scala/tools/nsc/symtab/Symbols.scala
index c21a606ec4..f3f48d3c72 100644
--- a/src/compiler/scala/tools/nsc/symtab/Symbols.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Symbols.scala
@@ -81,6 +81,11 @@ trait Symbols {
     }
 
     var attributes: List[AnnotationInfo] = List()
+    def hasAttribute(Tpe: Type): Boolean =
+      attributes.exists {
+        case AnnotationInfo(Tpe, _, _) => true
+        case _ => false
+    }
 
     var privateWithin: Symbol = _
 
diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index 944d271d1d..9494b3bba6 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -741,7 +741,7 @@ trait Namers { self: Analyzer =>
      *   - `abstract' modifier only for classes
      *   - `override' modifier never for classes
      *   - `def' modifier never for parameters of case classes
-     *   - declarations only in mixins or abstract classes
+     *   - declarations only in mixins or abstract classes (when not @native)
      */
     def validate(sym: Symbol): unit = {
       def checkNoConflict(flag1: int, flag2: int): unit =
@@ -769,12 +769,14 @@ trait Namers { self: Analyzer =>
           sym.isValueParameter && sym.owner.isClass && sym.owner.hasFlag(CASE))
         context.error(sym.pos, "pass-by-name arguments not allowed for case class parameters");
       if ((sym.flags & DEFERRED) != 0) {
-        if (!sym.isValueParameter && !sym.isTypeParameterOrSkolem &&
-            !context.tree.isInstanceOf[ExistentialTypeTree] &&
-            (!sym.owner.isClass || sym.owner.isModuleClass || sym.owner.isAnonymousClass)) {
-          context.error(sym.pos,
-            "only classes can have declared but undefined members" + varNotice(sym))
+        if (sym.hasAttribute(definitions.NativeAttr.tpe))
           sym.resetFlag(DEFERRED)
+        else if (!sym.isValueParameter && !sym.isTypeParameterOrSkolem &&
+          !context.tree.isInstanceOf[ExistentialTypeTree] &&
+          (!sym.owner.isClass || sym.owner.isModuleClass || sym.owner.isAnonymousClass)) {
+            context.error(sym.pos,
+              "only classes can have declared but undefined members" + varNotice(sym))
+            sym.resetFlag(DEFERRED)
         }
       }
       checkNoConflict(DEFERRED, PRIVATE)
diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index c81e28a398..f178590a42 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -692,6 +692,11 @@ abstract class RefChecks extends InfoTransform {
           validateVariance(sym, sym.info, CoVariance)
           validateVariance(sym, sym.typeOfThis, CoVariance)
 
+        case DefDef(mods, name, tparams, vparams, tpt, EmptyTree) if tree.symbol.hasAttribute(definitions.NativeAttr.tpe) =>
+          tree.symbol.resetFlag(DEFERRED)
+          result = transform(copy.DefDef(tree, mods, name, tparams, vparams, tpt,
+                typed(Apply(gen.mkAttributedRef(definitions.Predef_error), List(Literal("native method stub"))))))
+
         case DefDef(_, _, _, _, _, _) =>
           validateVariance(sym, sym.tpe, CoVariance) //@M TODO: might be affected by change in tpe --> can't use tree.tpe though
           checkDeprecatedOvers()
diff --git a/src/library/scala/native.scala b/src/library/scala/native.scala
new file mode 100644
index 0000000000..c49f0a0579
--- /dev/null
+++ b/src/library/scala/native.scala
@@ -0,0 +1,24 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2003-2007, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+// $Id: $
+
+
+package scala
+
+/**
+ * Marker for native methods.
+ * <p>
+ *   <code>@native def f(x: Int, y: List[Long]): String = ..</code>
+ * </p>
+ * <p>
+ *   Method body is not generated if method is marked with <code>@native</code>,
+ *   but it is type checked when present.
+ * </p>
+ */
+class native extends Annotation {}