implement typed Pointer type

lib/NativeCall.pm

@@ -65,7 +65,27 @@ sub return_hash_for(Signature $s, &r?, :$with-typeobj) {
     $result
 }
 
-my native long is repr("P6int") is Int is ctype("long") is export(:types, :DEFAULT) { };
+my native long       is Int is ctype("long")       is repr("P6int")    is export(:types, :DEFAULT) { };
+#~ my native longlong   is Int is ctype("longlong")   is repr("P6int")    is export(:types, :DEFAULT) { };
+#~ my native longdouble is Int is ctype("longdouble") is repr("P6num")    is export(:types, :DEFAULT) { };
+my class void                                      is repr('CPointer') is export(:types, :DEFAULT) { };
+my class Pointer                                   is repr('CPointer') is export(:types, :DEFAULT) { };
+
+# need to introduce the roles in there in an augment, because you can't
+# inherit from types that haven't been properly composed.
+use MONKEY_TYPING;
+augment class Pointer {
+    my role TypedPointer[::TValue = void] is Pointer is repr('CPointer') {
+        method of() { ::TValue }
+        method deref(::?CLASS:D \ptr:) { nativecast(::TValue, ptr) }
+    }
+    multi method PARAMETERIZE_TYPE(Mu:U \t) {
+        die "A types pointer can only hold integers, numbers, strings, CStructs, CPointers or CArrays (not {t.^name})"
+            unless t ~~ Int || t ~~ Num || t === Str || t.REPR eq 'CStruct' | 'CUnion' | 'CPPStruct' | 'CPointer' | 'CArray';
+        my \typed := TypedPointer[t];
+        typed.HOW.make_pun(typed);
+    }
+}
 
 # Gets the NCI type code to use based on a given Perl 6 type.
 my %type_map =
@@ -96,8 +116,8 @@ sub type_code_for(Mu ::T) {
     # the REPR of a Buf or Blob type object is Uninstantiable, so
     # needs an extra special case here that isn't covered in the
     # hash lookup above.
-    return 'vmarray'
-        if T ~~ Blob;
+    return 'vmarray'  if T ~~ Blob;
+    return 'cpointer' if T ~~ Pointer;
     die "Unknown type {T.^name} used in native call.\n" ~
         "If you want to pass a struct, be sure to use the CStruct representation.\n" ~
         "If you want to pass an array, be sure to use the CArray type.";