Brad,

> Yes, but if you don't want to implement this option, and I don't, it
> takes an hour for pred->cs to return on my Alpha.

As it would if you passed cs:full to cs-filter, which I am surmising would
be the simple and portable I-dont-want-to-limit-myself-to-7bit option.  And
if you specify cs:ascii to pred->cs, it will work just as you want cs-filter
to work.  pred->cs is just cs-filter with different default parameters.

> I don't see this.  Olin's email only mentions ASCII once in

cs-filter must start from some specified cs; my fear (and experience) is
that a client will explicitly code cs:ascii instead of cs:letter+digit, or
the appropriate union of more specific charsets.  I don't want to lock out
the Latin-1 chars by default.

With lazy filtering, I was also hoping to avoid redundantly reflecting the
system Unicode character table within the Scheme image.  Given the presence
of iterators and cs->list, perhaps this is futile.  You have the advantage
over me of having actually implemented this SRFI.

Whatever is decided, as long as we don't call pred 2**16 times by default,
I'm happier than otherwise.  I'm done.

Ben