Substantial relation kernel object

1 files changed, 18 insertions, 0 deletions

diff --git a/lib/protocols/Relation.ml b/lib/protocols/Relation.ml
new file mode 100644
index 0000000..ece9b8e
--- /dev/null
+++ b/lib/protocols/Relation.ml
@@ -0,0 +1,18 @@
+class type implementation = object
+  method heading : (Concepts.Hash.hash, Concepts.Condition.condition) result
+  method predicate : (Concepts.Hash.hash option, Concepts.Condition.condition) result
+  method local_constraints : (Concepts.Hash.hash option, Concepts.Condition.condition) result
+  method tuples : (Concepts.Hash.hash, Concepts.Condition.condition) result
+  method contains : Concepts.Blob.t -> (bool, Concepts.Condition.condition) result
+end
+
+type Handle.protocol += Relation of implementation
+type t = implementation
+
+let make impl = Relation (impl :> implementation)
+let from handle = Handle.into handle (function Relation impl -> Some impl | _ -> None)
+let heading i = Handle.invoke i (fun o -> o#heading)
+let predicate i = Handle.invoke i (fun o -> o#predicate)
+let local_constraints i = Handle.invoke i (fun o -> o#local_constraints)
+let tuples i = Handle.invoke i (fun o -> o#tuples)
+let contains i tuple = Handle.invoke i (fun o -> o#contains tuple)