X-Git-Url: http://git.tomasm.cz/fp.git/blobdiff_plain/2df2a815f76afa2daee4c7c5494e15795876003e..494e6afee1f1c583a880fca4e1f234de6823271a:/src/Lambda.hs?ds=inline diff --git a/src/Lambda.hs b/src/Lambda.hs index 5165bb8..54c4065 100644 --- a/src/Lambda.hs +++ b/src/Lambda.hs @@ -28,22 +28,38 @@ parseVar = do parseLambda :: Parser Term parseLambda = do char '\\' - (Var x) <- parseVar + vars <- sepBy1 parseVar (char ' ') char '.' t <- parseTerm - return $! Lambda x t + return $! createLambda vars t + +createLambda :: [Term] -> Term -> Term +createLambda (Var x : vs) t = Lambda x $ createLambda vs t +createLambda [] t = t +createLambda _ _ = error "createLambda failed" parseApp :: Parser Term parseApp = do + aps <- sepBy1 (parseBraces <|> parseLambda <|> parseVar) (char ' ') + return $! createApp aps + +createApp :: [Term] -> Term +createApp [t] = t +createApp (t:ts:tss) = createApp (App t ts : tss) +createApp [] = error "empty createApp" + +parseBraces :: Parser Term +parseBraces = do char '(' t <- parseTerm - char ' ' - r <- parseTerm char ')' - return $! App t r + return t parseTerm :: Parser Term -parseTerm = parseVar <|> parseLambda <|> parseApp +parseTerm = parseApp <|> + parseBraces <|> + parseLambda <|> + parseVar -------------------------------------------------