ephemeral relation kernel object

1 files changed, 36 insertions, 0 deletions

diff --git a/lib/kernel/EphemeralRelation.mli b/lib/kernel/EphemeralRelation.mli
new file mode 100644
index 0000000..d082394
--- /dev/null
+++ b/lib/kernel/EphemeralRelation.mli
@@ -0,0 +1,36 @@
+module type DERIVATION = sig
+  type plan
+
+  (** the hash of the plan, taken over the branch-local names of its
+      inputs rather than over their content addresses. The idea is to
+      have the same expression denote one object on every branch and
+      at every point in time. *)
+  val identity : plan -> Concepts.Hash.hash
+
+  val describe :
+    plan -> (Protocols.Schematics.relation_description, Concepts.Condition.condition) result
+
+  val modes : plan -> (Concepts.Mode.t, Concepts.Condition.condition) result
+
+  val generate :
+    plan ->
+    Protocols.Generative.binding ->
+    (Protocols.Handle.t, Concepts.Condition.condition) result
+end
+
+module Make (D : DERIVATION) : sig
+  (** unpinned, the identity of the derivation itself; pinned to a
+      branch commit, the identity of that derivation against one
+      reconstructible state, which is the only form for which equal
+      identity implies equal extension. *)
+  val identity : ?pinned:Concepts.Hash.hash -> D.plan -> Concepts.Hash.hash
+
+  (** edges are the handles the derivation reads, which are released
+      when the relation is also. Rejection of a derivation surfaces
+      here instead of when a cursor is being drained. *)
+  val derive :
+    ?pinned:Concepts.Hash.hash ->
+    ?edges:Protocols.Handle.t list ->
+    D.plan ->
+    (Protocols.Handle.t, Concepts.Condition.condition) result
+end