diff --git a/src/Data/Abstract/Eval3.hs b/src/Data/Abstract/Eval3.hs
index 8bb2f44d4..be852c3eb 100644
--- a/src/Data/Abstract/Eval3.hs
+++ b/src/Data/Abstract/Eval3.hs
@@ -4,6 +4,8 @@ module Data.Abstract.Eval3
 ( Evaluatable(..)
 , EnvironmentFor
 , step
+, require
+, Linker
 , MonadGC(..)
 , MonadFail(..)
 , Recursive(..)
@@ -19,6 +21,8 @@ import Control.Monad.Effect.Fail
 import Data.Abstract.Environment
 import Data.Abstract.FreeVariables
 import Data.Abstract.Value
+import Data.Abstract.Linker
+import Data.Semigroup
 import Data.Functor.Classes
 import Data.Proxy
 import Data.Term
@@ -29,6 +33,11 @@ import Data.Union (Apply)
 import qualified Data.Union as U
 
 
+require :: Members '[Fail, Reader (Linker v)] es => FilePath -> Eff es v
+require name = do
+  linker <- ask
+  maybe (fail ("cannot find " <> show name)) pure (linkerLookup name linker)
+
 -- a local and global environment binding variable names to addresses.
 -- class EvalEnv v m where
 --   askEnv :: m (Environment (LocationFor v) v)