diff --git a/src/common.rs b/src/common.rs
index 9b96d11052a9f93b869515d8e3a79e6a83a8af15..698ac11837209e13af4a196cc69036d1c85e89e6 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -1,7 +1,7 @@
 ///////////////////// PRELUDE /////////////////////
 
 pub use crate::protocol::{ComponentState, ProtocolDescription};
-pub use crate::runtime::{NonsyncContext, SyncContext};
+pub use crate::runtime::{NonsyncProtoContext, SyncProtoContext};
 
 pub use core::{
     cmp::Ordering,
@@ -140,3 +140,13 @@ impl Debug for PortId {
         write!(f, "PortId({},{})", self.controller_id, self.port_index)
     }
 }
+impl std::ops::Not for Polarity {
+    type Output = Self;
+    fn not(self) -> Self::Output {
+        use Polarity::*;
+        match self {
+            Putter => Getter,
+            Getter => Putter,
+        }
+    }
+}