Document (unimplemented) encoding of Shared values

1 files changed, 10 insertions, 0 deletions

diff --git a/docs/transient-0.md b/docs/transient-0.md
index 90a6c40..67632d6 100644
--- a/docs/transient-0.md
+++ b/docs/transient-0.md
@@ -35,6 +35,16 @@ This describes the current encoding of transient-0.
 * `List[T]`: the number of elements in the list encoded as per `Int64`, followed
   by each of the elements in the list encoded as per `T`.
 
+* `Shared[T]`: the first time a value is encountered, encoded as a unique ID as
+  per `Int64` followed by the encoding of the value itself as per `T`.
+
+  Any subsequent times that value is encountered, encoded as the unique ID as
+  per `Int64`.
+
+  Shared values should be assigned incremental IDs starting at zero. That is,
+  the first shared value should have an ID of 0, the second shared value should
+  have an ID of 1, and so on.
+
 * A struct is encoded by encoding each of its fields in definition order.
 
 * An enum is encoded by the index of the variant as per `Int32`.