cachedETagLookup :: FilePath -> IO ETagLookup
cachedETagLookup dir = do
    etags <- mkHashMap dir
    return $ (\f -> return $ M.lookup f etags)
cachedETagLookup :: FilePath -> IO ETagLookup
cachedETagLookup dir = do
    etags <- mkHashMap dir
    return $ (\f -> return $ M.lookup f etags)
cachedETagLookup dir = do
    etags <- mkHashMap dir
    return $ (\f -> return $ M.lookup f etags)