Current progress

datalog/src/Datalog/Parser.hs

@@ -1,18 +1,18 @@
 {-# LANGUAGE MultilineStrings #-}
 
-module Datalog.Parser
+module Datalog.Parser (
-    ( parseTerm
+    parseTerm,
-    , parseAtom
+    parseAtom,
-    , parseRule
+    parseRule,
-    , parseQuery
+    parseQuery,
-    , parseProgram
+    parseProgram,
-    )
+)
-  where
+where
 
-import Datalog.Syntax
 import Data.Text (Text)
 import Data.Text qualified as T
 import Data.Void (Void)
+import Datalog.Syntax
 import Text.Megaparsec
 import Text.Megaparsec.Char
 import Text.Megaparsec.Char.Lexer qualified as L
@@ -27,7 +27,8 @@ symbol :: (MonadParsec e Text m) => Text -> m Text
 symbol = L.symbol whitespace
 
 whitespace :: (MonadParsec e Text m) => m ()
-whitespace = L.space
+whitespace =
+    L.space
         space1
         (L.skipLineComment "--")
         (L.skipBlockComment "{-" "-}")
@@ -48,48 +49,54 @@ parseVar = Var () . VarId . T.pack <$> lexeme (liftA2 (:) upperChar (many alphaN
 parseTerm :: Parser Term
 parseTerm = parseVar <|> parseCon
 
-parseAtom :: Parser Atom
+parseAtom :: Parser (Atom' SrcLoc)
-parseAtom = do
+parseAtom = annotateSrcLoc $ do
     rel <- RelId . T.pack <$> lexeme (liftA2 (:) lowerChar (many alphaNumChar))
     args <- parens (parseTerm `sepBy` comma)
     return (Atom () rel args)
 
-parseQuery :: Parser [Atom]
+parseQuery :: Parser [Atom' SrcLoc]
 parseQuery = parseAtom `sepBy` comma
 
-parseFact :: Parser Rule
+parseFact :: Parser (Rule' SrcLoc)
-parseFact = do
+parseFact = annotateSrcLoc $ do
     headAtom <- parseAtom
     period
-  return (Rule () headAtom [])
+    return (Rule NoLoc headAtom [])
 
-parseRule :: Parser Rule
+parseRule :: Parser (Rule' SrcLoc)
-parseRule = try parseFact <|> do
+parseRule =
+    annotateSrcLoc $
+        try parseFact <|> do
             headAtom <- parseAtom <* symbol ":-"
             bodyAtoms <- parseQuery
             period
-  return (Rule () headAtom bodyAtoms)
+            return (Rule NoLoc headAtom bodyAtoms)
 
-parseProgram :: Parser Program
+parseProgram :: Parser (Program' SrcLoc)
-parseProgram = Program () <$> many parseRule
+parseProgram = annotateSrcLoc $ Program NoLoc <$> many parseRule
 
-annotateSrcLoc :: Functor f => Parser (f a) -> Parser (f SrcLoc)
+annotateSrcLoc :: (Functor f) => Parser (f a) -> Parser (f SrcLoc)
 annotateSrcLoc p = do
     s <- getSourcePos
     res <- p
     f <- getSourcePos
     pure (SrcLoc s f <$ res)
 
-data SrcLoc = SrcLoc
+data SrcLoc
+    = SrcLoc
         { start :: SourcePos
         , end :: SourcePos
-  } deriving Show
+        }
+    | NoLoc
+    deriving (Show)
 
 test = do
     let r = runParser parseProgram "???" prog
     pPrint @IO r
 
-prog = """
+prog =
+    """
     odd(X,Y) :- r(X,Y).
     odd(X,Y) :- even(X,Z), r(Z,Y).
     even(X,Y) :- odd(X,Z), r(Z,Y).

datalog/src/Datalog/Syntax.hs

@@ -48,6 +48,16 @@ type Program = Program' ()
 data Program' a = Program a [Rule' a]
   deriving (Eq, Ord, Show)
 
+class Decorable t where
+    decorateNode :: a -> t a -> t a
+
+instance (Decorable Program') where decorateNode x (Program _ rs) = Program x rs
+instance (Decorable Rule') where decorateNode x (Rule _ a as) = Rule x a as
+instance (Decorable Atom') where decorateNode x (Atom _ relId ts) = Atom x relId ts
+instance (Decorable Term') where 
+    decorateNode x (Var _ varId) = Var x varId
+    decorateNode x (Con _ conId) = Con x conId
+
 class HasConstants a where
   constants :: a -> Set ConId