From fe899bbb0c4224c298d30f5ecb4c4431ba999046 Mon Sep 17 00:00:00 2001
From: Felix Dilke <felix.dilke@obsidian.systems>
Date: Thu, 29 Jan 2026 16:42:53 +0000
Subject: [PATCH] introduce typeclass

---
 haskell-experiments/src/Datalog/NaiveDatabase.hs | 12 +++++++++---
 haskell-experiments/src/Datalog/Rules.hs         |  5 +++++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/haskell-experiments/src/Datalog/NaiveDatabase.hs b/haskell-experiments/src/Datalog/NaiveDatabase.hs
index 1727fe1..81e62ae 100644
--- a/haskell-experiments/src/Datalog/NaiveDatabase.hs
+++ b/haskell-experiments/src/Datalog/NaiveDatabase.hs
@@ -3,6 +3,7 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
+{-# LANGUAGE InstanceSigs #-}
 
 module Datalog.NaiveDatabase where
 
@@ -25,13 +26,18 @@ data NaiveDatabase = NaiveDatabase
   } deriving (Show, Eq)
 
 
-emptyDB :: NaiveDatabase
-emptyDB =
-  NaiveDatabase
+instance DatalogDB NaiveDatabase where
+  emptyDB :: NaiveDatabase
+  emptyDB =   NaiveDatabase
     { relations = Map.empty
     , constants = Set.empty -- the Herbrand universe
     }
 
+  -- lookupRelation :: NaiveDatabase -> Text -> Maybe Relation -> NaiveDatabase
+  -- lookupRelation = _
+  -- insertRelation :: NaiveDatabase -> Text -> Relation -> NaiveDatabase
+  -- insertRelation = _
+
 lookupRelation :: RelationId -> Map RelationId Relation -> Int -> Set [Term] -> Relation
 lookupRelation relationName relationMap newArity tuples =
   case Map.lookup relationName relationMap of
diff --git a/haskell-experiments/src/Datalog/Rules.hs b/haskell-experiments/src/Datalog/Rules.hs
index 20a5c9e..a0b1f8f 100644
--- a/haskell-experiments/src/Datalog/Rules.hs
+++ b/haskell-experiments/src/Datalog/Rules.hs
@@ -46,3 +46,8 @@ data Relation = Relation
 -- Our constants will be the terms of the Datalog grammar - ints/variables/symbols
 type Constant = Term
 type RelationId = Text
+
+class DatalogDB db where
+  emptyDB :: db
+  -- lookupRelation :: db -> Text -> Maybe Relation -> db
+  -- insertRelation :: db -> Text -> Relation -> db