> Cursors don't necessarily belong to a disjoint type.  In Chibi they do,
> but they could also be implemented as negative exact integers or by some
> other means.
I see. However, if this is the case, it's rather impossible to implement a
procedure that takes either index or cursor such as string-every defined in
the SRFI. (I know there's string-index->cursor, but there's no way to signal
a type error before calling the SRFI procedures, if I'm not mistaken.)

Cheer,
--
_/_/
Takashi Kato
E-mail: ktakashi19@gmail.com