pyrites/haskell-experiments/src/Datalog/NaiveQE.hs

{-# HLINT ignore "Redundant flip" #-}
-- {-# LANGUAGE ImportQualifiedPost #-}
-- {-# LANGUAGE InstanceSigs #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
{-# LANGUAGE BlockArguments #-}
{-# HLINT ignore "Redundant flip" #-}
{-# LANGUAGE ImportQualifiedPost #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
{-# LANGUAGE InstanceSigs #-}
{-# LANGUAGE BlockArguments #-}

module Datalog.NaiveQE where
import Datalog.QueryEngine
import Data.Text
import Data.Map (Map)
import Data.Map qualified as Map
import Datalog.DatalogDB
import Datalog.DatalogParser
import Control.Exception

data (DatalogDB db) => NaiveQE db = NaiveQE 
  {
    db :: db,
    herbrand :: Map Text Relation
  } deriving (Show, Eq)

instance QueryEngine NaiveQE where
  queryEngine :: (DatalogDB db) => db -> NaiveQE db
  queryEngine db = NaiveQE { 
    db = db,
    herbrand = computeHerbrand db
  }
  query :: (DatalogDB db) => NaiveQE db -> Text -> Text
  query qe queryText =
    case parseDatalog queryText of
      Right (Query texts literals) -> "#NYI"
      Right otherStatement -> throw $ NonQueryException queryText otherStatement
      Left ex -> throw $ CannotParseStatementException queryText ex

computeHerbrand :: (DatalogDB db) => db -> Map Text Relation
computeHerbrand db =
  computeHerbrandSub Map.empty where
  computeHerbrandSub :: Map Text Relation -> Map Text Relation
  computeHerbrandSub facts = facts
    -- for_ (Map.toList myMap) $ \(k,v) ->