Support AnyPointer constant values.

The trick here is that you must specify the value as a separate constant with a defined type. Then, you can reference that constant where an AnyPointer is expected.

Eventually we should maybe support some sort of inline syntax that specifies a type explicitly...

c++/src/capnp/compiler/node-translator.c++

@@ -2726,6 +2726,15 @@ kj::Maybe<Orphan<DynamicValue>> ValueTranslator::compileValue(Expression::Reader
         if (result.getReader().as<DynamicList>().getSchema() == type.asList()) {
           return kj::mv(result);
         }
+      } else if (type.isAnyPointer()) {
+        switch (type.whichAnyPointerKind()) {
+          case schema::Type::AnyPointer::Unconstrained::ANY_KIND:
+          case schema::Type::AnyPointer::Unconstrained::LIST:
+            return kj::mv(result);
+          case schema::Type::AnyPointer::Unconstrained::STRUCT:
+          case schema::Type::AnyPointer::Unconstrained::CAPABILITY:
+            break;
+        }
       }
       break;
 
@@ -2742,6 +2751,15 @@ kj::Maybe<Orphan<DynamicValue>> ValueTranslator::compileValue(Expression::Reader
         if (result.getReader().as<DynamicStruct>().getSchema() == type.asStruct()) {
           return kj::mv(result);
         }
+      } else if (type.isAnyPointer()) {
+        switch (type.whichAnyPointerKind()) {
+          case schema::Type::AnyPointer::Unconstrained::ANY_KIND:
+          case schema::Type::AnyPointer::Unconstrained::STRUCT:
+            return kj::mv(result);
+          case schema::Type::AnyPointer::Unconstrained::LIST:
+          case schema::Type::AnyPointer::Unconstrained::CAPABILITY:
+            break;
+        }
       }
       break;
 

c++/src/capnp/encoding-test.c++

@@ -1640,6 +1640,16 @@ TEST(Encoding, Constants) {
   checkList(*test::TestConstants::ENUM_LIST_CONST, {TestEnum::FOO, TestEnum::GARPLY});
 }
 
+TEST(Encoding, AnyPointerConstants) {
+  auto reader = test::ANY_POINTER_CONSTANTS.get();
+
+  EXPECT_EQ("baz", reader.getAnyKindAsStruct().getAs<TestAllTypes>().getTextField());
+  EXPECT_EQ("baz", reader.getAnyStructAsStruct().as<TestAllTypes>().getTextField());
+
+  EXPECT_EQ(111111111, reader.getAnyKindAsList().getAs<List<int32_t>>()[0]);
+  EXPECT_EQ(111111111, reader.getAnyListAsList().as<List<int32_t>>()[0]);
+}
+
 TEST(Encoding, GlobalConstants) {
   EXPECT_EQ(12345u, test::GLOBAL_INT);
   EXPECT_EQ("foobar", test::GLOBAL_TEXT.get());

c++/src/capnp/test.capnp

@@ -743,6 +743,21 @@ const embeddedData :Data = embed "testdata/packed";
 const embeddedText :Text = embed "testdata/short.txt";
 const embeddedStruct :TestAllTypes = embed "testdata/binary";
 
+struct TestAnyPointerConstants {
+  anyKindAsStruct @0 :AnyPointer;
+  anyStructAsStruct @1 :AnyStruct;
+  anyKindAsList @2 :AnyPointer;
+  anyListAsList @3 :AnyList;
+
+}
+
+const anyPointerConstants :TestAnyPointerConstants = (
+  anyKindAsStruct = TestConstants.structConst,
+  anyStructAsStruct = TestConstants.structConst,
+  anyKindAsList = TestConstants.int32ListConst,
+  anyListAsList = TestConstants.int32ListConst,
+);
+
 interface TestInterface {
   foo @0 (i :UInt32, j :Bool) -> (x :Text);
   bar @1 () -> ();