gengeng

[clean-tests.git] / uds / ASDS / Source.dcl

diff --git a/uds/ASDS/Source.dcl b/uds/ASDS/Source.dcl
index ab3446b..3838e0e 100644 (file)
--- a/uds/ASDS/Source.dcl
+++ b/uds/ASDS/Source.dcl
@@ -1,6 +1,6 @@
 definition module ASDS.Source
 
-from ASDS import class read, class write
+from ASDS import class read, class write, class observe
 from Control.Monad import class Monad
 from Control.Applicative import class Applicative, class <*>, class pure
 from Data.Functor import class Functor
@@ -21,6 +21,7 @@ source :: (p -> m r) (p w -> m ()) -> Source m p r w | pure m
 
 instance read ReadSource, (RWPair sdsr sdsw) | read sdsr
 instance write WriteSource, (RWPair sdsr sdsw) | write sdsw
+instance observe WriteSource, (RWPair sdsr sdsw) | observe sdsw
 
 //* Immediately returns the given value on a read
 constShare :: a -> ReadSource m p a b | pure m