Current progress

datalog/src/Datalog/Parser.hs

@@ -1,18 +1,18 @@
 {-# LANGUAGE MultilineStrings #-}
 
-module Datalog.Parser
-    ( parseTerm
-    , parseAtom
-    , parseRule
-    , parseQuery
-    , parseProgram
-    )
-  where
+module Datalog.Parser (
+    parseTerm,
+    parseAtom,
+    parseRule,
+    parseQuery,
+    parseProgram,
+)
+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 "{-" "-}")
@@ -39,54 +40,63 @@ comma, period :: (MonadParsec e Text m) => m ()
 comma = () <$ symbol ","
 period = () <$ symbol "."
 
-parseCon :: (MonadParsec e Text m) => m (Term' SrcLoc)
-parseCon = Con dummy . ConId . T.pack <$> lexeme (liftA2 (:) (numberChar <|> lowerChar) (many alphaNumChar))
+parseCon :: (MonadParsec e Text m) => m Term
+parseCon = Con () . ConId . T.pack <$> lexeme (liftA2 (:) (numberChar <|> lowerChar) (many alphaNumChar))
 
-parseVar :: (MonadParsec e Text m) => m (Term' SrcLoc)
-parseVar = Var dummy . VarId . T.pack <$> lexeme (liftA2 (:) upperChar (many alphaNumChar))
+parseVar :: (MonadParsec e Text m) => m Term
+parseVar = Var () . VarId . T.pack <$> lexeme (liftA2 (:) upperChar (many alphaNumChar))
 
-parseTerm :: Parser (Term' SrcLoc)
+parseTerm :: Parser Term
 parseTerm = parseVar <|> parseCon
 
 parseAtom :: Parser (Atom' SrcLoc)
-parseAtom = do
-  p <- getSourcePos
+parseAtom = annotateSrcLoc $ do
     rel <- RelId . T.pack <$> lexeme (liftA2 (:) lowerChar (many alphaNumChar))
     args <- parens (parseTerm `sepBy` comma)
-  return (Atom SrcLoc{start = p} rel args)
+    return (Atom () rel args)
 
 parseQuery :: Parser [Atom' SrcLoc]
 parseQuery = parseAtom `sepBy` comma
 
 parseFact :: Parser (Rule' SrcLoc)
-parseFact = do
-  p <- getSourcePos
+parseFact = annotateSrcLoc $ do
     headAtom <- parseAtom
     period
-  return (Rule SrcLoc{start = p} headAtom [])
+    return (Rule NoLoc headAtom [])
 
 parseRule :: Parser (Rule' SrcLoc)
-parseRule = try parseFact <|> do
-  p <- getSourcePos
+parseRule =
+    annotateSrcLoc $
+        try parseFact <|> do
             headAtom <- parseAtom <* symbol ":-"
             bodyAtoms <- parseQuery
             period
-  return (Rule SrcLoc{start = p} headAtom bodyAtoms)
+            return (Rule NoLoc headAtom bodyAtoms)
 
 parseProgram :: Parser (Program' SrcLoc)
-parseProgram = Program dummy <$> many parseRule
+parseProgram = annotateSrcLoc $ Program NoLoc <$> many parseRule
 
-data SrcLoc = 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
         { start :: SourcePos
-  -- , end :: (Word, Word)
-  } deriving Show
-dummy = SrcLoc{start = initialPos "dummy-file"}
+        , end :: SourcePos
+        }
+    | 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