Arne wrote:
Indeed, Scheme doesn't have a clear separation between full-featured
RnRS implementations and subset implementation. Several people have
noted that this is confusing.
Maybe the r7rs-benchmark preludes and postludes could be a start for
documentation of that?
https://github.com/ecraven/r7rs-benchmarks/tree/master/src
Example: Guile3-prelude.scm:
https://github.com/ecraven/r7rs-benchmarks/blob/master/src/Guile3-prelude.scm
(use-modules (ice-9 rdelim))
(define-syntax import
(syntax-rules ()
((import stuff ...)
(begin) ;; do nothing
)))
(define flush-output-port force-output)
(define current-second current-time)
(define (jiffies-per-second) internal-time-units-per-second)
(define current-jiffy get-internal-real-time)
(define exact inexact->exact)
(define inexact exact->inexact)
(define (square x) (* x x))
(define (write-string str out) (display str out)) ; sufficient for tail.scm
(define (this-scheme-implementation-name) (string-append "guile3-"
(version)))
(read-enable 'r7rs-symbols)
(print-enable 'r7rs-symbols)
(use-modules (rnrs bytevectors)
(rnrs base)
(srfi srfi-9))
Those might be a good start for filling in the gaps in RnRS support.
Some Scheme implemenetations have existing RnRS test suites. IIRC those
are mostly cloned and hacked from Clinger's tests for Larceny. A test
suite has the advantage that it is executable documentation of RnRS
compatibility. Manual documentation is prone to mistakes.
Could some of those be eligible to be merged into (guile-user) — the
interactive module of the REPL?
I'm not qualified to answer that one.
Is (import (srfi :N)) portable in practice?
AFAIK:
(import (srfi :N)) is portable across all R6RS implementations.
(import (srfi N)) - without the colon - is portable across all R7RS
implementations.
[...]
Thank you for the overview!
Do you want to cross-post this part of your answer to the srfi-list?
You're welcome. I think I have posted an equivalent overview to
srfi-discuss in the past, but I can't find it.
R7RS has an (include "...") mechanism which R6RS lacks. chez-srfi adds
a similar mechanism on top of the R6RS library system. The chez-srfi
mechanism is widely portable in practice.
Does that work the same as Guile’s (include "...")?
From the reference manual:
-- Scheme Syntax: include file-name
Open FILE-NAME, at expansion-time, and read the Scheme forms that
it contains, splicing them into the location of the ‘include’,
within a ‘begin’.
If FILE-NAME is a relative path, it is searched for relative to the
path that contains the file that the ‘include’ form appears in.
[...]
Yes, Guile's include sounds very similar to R7RS include. There may be
obscure technical differences, but the intent is exactly the same.
