1 files changed, 24 insertions, 0 deletions
diff --git a/lib/ocaml_rts/linksem/src_lem_library/either.ml b/lib/ocaml_rts/linksem/src_lem_library/either.ml
new file mode 100644
index 00000000..ddf1b214
--- /dev/null
+++ b/lib/ocaml_rts/linksem/src_lem_library/either.ml
@@ -0,0 +1,24 @@
+type ('a, 'b) either = 
+  | Left of 'a
+  | Right of 'b
+
+let either_case fa fb x = match x with
+  | (Left a) -> fa a
+  | (Right b) -> fb b
+
+let eitherEqualBy eql eqr (left: ('a, 'b) either) (right: ('a, 'b) either) =  
+  match (left, right) with
+    | ((Left l), (Left l')) -> eql l l'
+    | ((Right r), (Right r')) -> eqr r r'
+    | _ -> false
+  
+let rec either_partition l = ((match l with
+  | [] -> ([], [])
+  | x :: xs -> begin
+      let (ll, rl) = (either_partition xs) in
+      (match x with 
+        | (Left l) -> ((l::ll), rl)
+        | (Right r) -> (ll, (r::rl))
+      )
+    end
+))