Taylan Ulrich Bayırlı/Kammer scripsit:

> I think it would be better if it re-exported string-related procedures
> in R7RS.  That way, one can import the SRFI without importing the R7RS
> base and still get a full-fledged string library.  (Maybe one has an
> alternative to (scheme base), some sort of DSL.)

Running without a base of some sort, whether (scheme r5rs), (rnrs
base), or (scheme base), is a pretty specialized use case that I think
could be safely left to local adaptation.  If you have an R6RS or R7RS
style library system, you can always import just the procedures you
want.  The only new string-related procedures in R7RS are string-map,
string-for-each, string->vector, vector->string, and string-copy!, each
of which is trivial and none of which are required by the portable
implementation.  In addition, some R7RS string procedures support
start/end arguments even though their R5RS counterparts do not.

The fact that SRFI 1 theoretically exports primitives like car, cdr, and
cons, as well as non-primitive but overwhelmingly common procedures like
length, has never been anything but a theoretical wart and a practical
nuisance.  SRFI 13 excludes R5RS `string=?` (it has a different procedure
for string equality), and there was a lot of confusion on the SRFI 13
mailing list about whether conforming to SRFI 13 required removing or
hiding `string=?` from one's implementation (this is before library
systems were commonplace in Schemes).  If (as I assume) SRFI 1 becomes
the (scheme list) library in R7RS-large, I will add a note saying that
the R7RS-small procedures are not imported by (import (scheme list)).

At some point someone should write a portable and comprehensive R7RS
shim that provides every procedure in the R7RS library using only the
R5RS library, analogous to the various syntax expanders.  At the moment,
most of my SRFI sample implementations are written in R7RS but come with
minimal shims that provide what is needed to let them run on Chicken at
least: adaptation to other R5RS+ systems should be straightforward.

--
John Cowan          http://www.ccil.org/~cowan        xxxxxx@ccil.org
"But I am the real Strider, fortunately," he said, looking down at them
with his face softened by a sudden smile.  "I am Aragorn son of Arathorn,
and if by life or death I can save you, I will."