filling out the DB

haskell-experiments/src/Datalog/NaiveDatabase.hs

@@ -23,14 +23,25 @@ data Value =
   ValueSymbol String
 
 data NaiveDatabase = NaiveDatabase {
-  relations :: Map Text Int,
+  relations :: Map RelationId Relation,
-  values :: Set Value 
+  constants :: Set ConstantId
 }
 
+data Relation = Relation {
+  arity :: Int,
+  tuples :: Set [ConstantId]
+}
+
+newtype RelationId = RelationId Text
+  deriving (Eq, Ord, Show)
+
+newtype ConstantId = ConstantId Text
+  deriving (Eq, Ord, Show)
+
 emptyDB :: NaiveDatabase
 emptyDB = NaiveDatabase {
   relations = Map.empty,
-  values = Set.empty
+  constants = Set.empty
 }
 
 withFacts :: [Text] -> NaiveDatabase

haskell-experiments/test/Test/Datalog/NaiveDatabaseSpec.hs

@@ -23,6 +23,19 @@ import qualified Datalog.NaiveDatabase as NaiveDatabase
 -- checkEval text expectedVal = 
 --   fmap eval (parse parseExpr "" text) `shouldBe` Right expectedVal
 
+-- getConfig :: IO Config
+-- getConfig = do
+--   env <- lookupEnv "APP_ENV"
+--   let fallbackHosts =
+--         [ "localhost:8080"
+--         , "127.0.0.1:9000"
+--         , "backup.example.com"
+--         ]
+--   pure Config
+--     { port     = 3000
+--     , hosts    = fromMaybe fallbackHosts env
+--     , logLevel = Info
+--     }
 
 spec :: Spec
 spec = do
@@ -30,7 +43,26 @@ spec = do
     it "..." $ do
       1 `shouldBe` (1 :: Int)
     it "can accept facts and do basic queries" $ do
-      let twig = [ "xx", "yy "]
+      -- let fallbackHosts =
-      let pig = [ "parent(\"alice\", \"bob\").", "parent(\"bob\", \"carol\")." ]
+      --       [ "localhost:8080"
-      let db = NaiveDatabase.withFacts [ "parent(\"alice\", \"bob\").", "parent(\"bob\", \"carol\")." ]
+      --       , "127.0.0.1:9000"
+      --       , "backup.example.com"
+      --       ]
+      -- let names =
+      --       [ "Alice"
+      --       , "Bob"
+      --       , "Charlie"
+      --       , "Daphne"
+      --       , "Eve"
+      --       ]
+      -- let twig = 
+      --       [ "xx"
+      --       , "yy "  ]
+      -- let pig = 
+      --       [ "parent(\"alice\", \"bob\")."
+      --       , "parent(\"bob\", \"carol\")." 
+      --       ]
+      let db = NaiveDatabase.withFacts 
+            [ "parent(\"alice\", \"bob\")."
+            , "parent(\"bob\", \"carol\")." ]
       query  db"?- parent(alice,X)." `shouldBe` "#NYI" -- ideally, 'bob'