Alex Shinn wrote:

> I totally missed that - the chibi versions have never taken
> an initial string argument to string-cursor</>[=]?.  Do we
> really need it?

SRFI 130, as it exists today (on what I believe to be the last
day before it enters final status), says those cursor comparison
procedures take three arguments, the first being a string.  So
long as SRFI 130 says that, the sample implementations need to
take that number of arguments.

As for whether we really need SRFI 130, that's a different
question.  I think the better approach is to define a new
data type of immutable texts, using strings only for those
few use cases that really need mutation.  Immutable texts
can combine O(1)-time random access with the spatial efficiency
associated with UTF-8.  John Cowan had written a proposal along
these lines, but he called them spans instead of texts and made
the proposed specification more complicated than necessary.

I suspect that is why SRFI 130 was written.  In my opinion,
however, SRFI 130 doesn't do the job that needs doing.

I spent this morning writing a test program for Larceny's
implementation of SRFI 130, which is a fairly simple wrapper
around Olin's reference implementation for SRFI 13.  The test
program assumes cursors are the same as indexes, but it may
be of some interest regardless.  The test program is in
lib/SRFI/test/srfi-130-test.sps7 at Larceny's development
site, https://github.com/larcenists/larceny

That test program uncovered two very old bugs in Olin's
implementation of SRFI 13, and it might be a good idea for
people who are using that old implementation as a starting
point for SRFI 130 to be aware of those bugs.  Basically,
Olin's definitions of string-filter and string-delete swapped
the order of the first two arguments, and his definition of
string-trim-right ignored the optional start argument.  For
details, see the history of Larceny's lib/SRFI/srfi/%3a13.sls
file.  Note also that the test program many of us have been
using for SRFI 13 contains incorrect tests that sanctioned
those bugs.

Will