1 files changed, 32 insertions, 0 deletions
diff --git a/lib/condition.ml b/lib/condition.ml
new file mode 100644
index 0000000..72eb773
--- /dev/null
+++ b/lib/condition.ml
@@ -0,0 +1,32 @@
+
+class type serializable = object
+  method as_sexp : Sexplib.Sexp.t
+end
+
+class literal (expr : Sexplib.Sexp.t) : serializable = object
+  method as_sexp = expr
+end
+
+let of_sexp (expr : Sexplib.Sexp.t) = new literal expr
+let of_string (s : string) = new literal (Sexplib.Sexp.Atom s)
+
+type condition = { name : string; properties : (string, serializable) BatMap.t }
+
+let condition name ?parent props =
+  { name;
+    properties =
+      parent
+      |> Option.map (fun { properties; _ } -> properties)
+      |> Option.value ~default:BatMap.empty
+      |> props }
+
+let ( |=| ) name value = (fun p -> BatMap.add name value p)
+let ( & ) l r = (fun p -> r (l p))
+
+let to_sexp { name; properties } =
+  let open Sexplib.Sexp in
+  let properties' =
+    BatMap.to_seq properties
+    |> BatSeq.map (fun (k, v) -> List [Atom k; v#as_sexp])
+    |> BatList.of_seq in
+  List (Atom name :: properties')