Shiro Kawai scripsit:

> - For such text manipulation library, I'd like to have things like these:
>   (span-replace span span2 from to)  - replace span's range between from
>   and to with span2, from and to are cursors.

No need for ''from'' and to, really.  Just append everything before from,
the replaced subspan, and everything after ''to''.

>   Curiously, srfi-13 has string-replace but srfi-130 doesn't.  Why?

An oversight.  I'll add it back.

>   (span-substitute span pattern replacement) - replace occurrence of
>   pattern span by replacement span

It's omitted on purpose, as I didn't want to make this library dependent
on a regex library.

> - Given on the cheap concatenation, span-join may be unnecessary, for
>   making interleaved list and span-concatenate can be just about as
>   efficient.

Yes, the purpose of -join is primarily convenience, not efficiency.
Inserting spaces or commas between items in a list is something that's
frequently done.

> - I doubt individual character-level operations such as -filter, -remove,
> -partition is as useful in the context of high-level text manipulation.

I actually doubt they are useful at all, since they basically treat
strings and spans as character bags.  That may make some sense for strings
because of their literal form and typically compact representation,
but not really for spans.  I'll remove them from the next draft.

--
John Cowan          http://www.ccil.org/~cowan        xxxxxx@ccil.org
What asininity could I have uttered that they applaud me thus?
        --Phocion, Greek orator