a bit more safe coding

LeventErkok · Nov 5, 2024 · 86b1063 · 86b1063
1 parent 89fd5b2
commit 86b1063
Showing 1 changed file with 14 additions and 6 deletions.
diff --git a/Documentation/SBV/Examples/Puzzles/DieHard.hs b/Documentation/SBV/Examples/Puzzles/DieHard.hs
@@ -56,12 +56,20 @@ type CState = State Integer  Action
 instance Queriable IO SState where
   type QueryResult SState = CState
 
-  create                            = State <$> freshVar_    <*> freshVar_      <*> freshVar_
-  project State{big, small, action} = State <$> getValue big <*> getValue small <*> getValue action
-  embed   State{big, small, action} = pure $ State { big    = literal big
-                                                   , small  = literal small
-                                                   , action = literal action
-                                                   }
+  create = State <$> freshVar_ <*> freshVar_ <*> freshVar_
+
+  project State{big, small, action} = do b <- getValue big
+                                         s <- getValue small
+                                         a <- getValue action
+                                         pure $ State { big    = b
+                                                      , small  = s
+                                                      , action = a
+                                                      }
+
+  embed State{big, small, action} = pure $ State { big    = literal big
+                                                 , small  = literal small
+                                                 , action = literal action
+                                                 }
 
 -- | Solve the problem using a BMC search. We have:
 --