X-Git-Url: http://git.tomasm.cz/fp.git/blobdiff_plain/e9fefc72cffd266f05269f87992606365f8bd57a..1e130750a3014baa6328e323ef877e7f7839d925:/src/Lambda.hs?ds=sidebyside diff --git a/src/Lambda.hs b/src/Lambda.hs index f9fbe2b..54c4065 100644 --- a/src/Lambda.hs +++ b/src/Lambda.hs @@ -28,7 +28,7 @@ parseVar = do parseLambda :: Parser Term parseLambda = do char '\\' - vars <- many1 (parseVar <* char ' ') + vars <- sepBy1 parseVar (char ' ') char '.' t <- parseTerm return $! createLambda vars t @@ -40,15 +40,26 @@ 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 -------------------------------------------------