now fully computing the herbrand, maybe incorrectly

haskell-experiments/src/Datalog/NaiveQE.hs

@@ -21,6 +21,9 @@ import Utility.Utility
 import Control.Monad(guard)
 import Data.Set (Set)
 import Data.Set qualified as Set
+import Data.Functor ((<&>))
+import Data.List (nub)
+import qualified Data.List.NonEmpty as List
 
 data (DatalogDB db) => NaiveQE db = NaiveQE 
   {
@@ -68,20 +71,30 @@ computeHerbrand db =
       foldr amalgamateRule newFacts (_rules relation) where
       amalgamateRule :: RelationRule -> NewFacts -> NewFacts
       amalgamateRule (RelationRule headVars bodyElements) newFacts  =
-        newFacts where
-        (facts, changed) = newFacts
+        if stillChanged then
+          (updatedFacts, True)
+        else newFacts
+        where
+        (facts, wasChanged) = newFacts
+        latestRelation = facts Map.! (_name relation)
         knownTuples :: Set [Constant] = 
-          _tuples $ facts Map.! (_name relation)
+          _tuples $ latestRelation
         extraTuples = do
           varmap <- allMaps headVars (Set.toList $ allConstants db)
           let tuple = (\name -> varmap Map.! name) <$> headVars
           guard $ not $ Set.member tuple knownTuples
-          let twig :: Int -> Int -> Int
-              twig x y = x + y
-              satisfied :: RuleBodyElement -> Bool
-              satisfied (RuleBodyElement subRelationId ruleElements) = all (satisfiedSub (facts Map.! subRelationId)) ruleElements
-              satisfiedSub :: Relation -> RuleElement -> Bool
-              satisfiedSub subRelation ruleElement = True
+          let satisfied :: RuleBodyElement -> Bool
+              satisfied (RuleBodyElement subRelationId ruleElements) = 
+                let subRelation = facts Map.! subRelationId
+                    mappedTuple = ruleElements <&> \ruleElement ->
+                      case ruleElement of
+                        RuleElementConstant constant -> constant
+                        RuleElementVariable index -> tuple !! index
+                in Set.member mappedTuple (_tuples subRelation)
           guard $ all satisfied bodyElements
-          return varmap
+          return tuple
+        stillChanged = wasChanged || (not (null extraTuples))
+        updatedTuples = Set.union knownTuples $ Set.fromList extraTuples 
+        updatedFacts = Map.insert (_name relation) (
+          latestRelation { _tuples = updatedTuples }) facts