[GR-4777] Move RMain, implement TruffleLanguage.isObjectOfLanguage.

com.oracle.truffle.r.engine/src/com/oracle/truffle/r/engine/TruffleRLanguageImpl.java

@@ -107,7 +107,7 @@ public final class TruffleRLanguageImpl extends TruffleRLanguage implements Scop
 
     @Override
     protected boolean isObjectOfLanguage(Object object) {
-        return false;
+        return object instanceof RTypedValue;
     }
 
     @Override

com.oracle.truffle.r.launcher/src/com/oracle/truffle/r/launcher/RMain.java → com.oracle.truffle.r.engine/src/com/oracle/truffle/r/engine/shell/RMain.java

@@ -20,7 +20,10 @@
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
-package com.oracle.truffle.r.launcher;
+package com.oracle.truffle.r.engine.shell;
+
+import com.oracle.truffle.r.launcher.RCommand;
+import com.oracle.truffle.r.launcher.RscriptCommand;
 
 /**
  * Convenience class that allows the R/Rscript entry to be chosen by an initial argument.
@@ -66,5 +69,4 @@ public class RMain {
         System.arraycopy(args, 1, nargs, 0, nargs.length);
         return nargs;
     }
-
 }