symbPairs :: GenParser Char st [(IRI, Maybe IRI)]
symbPairs = uriPair >>= \ u -> do
    commaP `followedWith` uriP
    us <- symbPairs
    return $ u : us
  <|> return [u]
symbPairs :: GenParser Char st [(IRI, Maybe IRI)]
symbPairs = uriPair >>= \ u -> do
    commaP `followedWith` uriP
    us <- symbPairs
    return $ u : us
  <|> return [u]
symbPairs = uriPair >>= \ u -> do
    commaP `followedWith` uriP
    us <- symbPairs
    return $ u : us
  <|> return [u]