After a few rounds of golf I have arrived at this minimal demonstration
of a problem where the arguments that a C function receives are not
the arguments it is given.
Originally the *wtf* let also declared an integer to look up but
this was removed by the golf. If it were still there then only the
*wtf* let and the final (map) would be necessary to see the problem
occur. Everything else is here to demonstrate the problem not
occurring.
I have tested with today's s7 tarball.
(require cload.scm)
; This is broken:
(define *wtf* (let ()
(c-define `(
(C-function ("anything" _anything "..." 2))
(in-C "static s7_pointer
_anything (s7_scheme *sc, s7_pointer args)
{
printf(\"%s\", s7_object_to_c_string(sc, args));
return s7_nil(sc);
}"))
"" () "" "" "libs7crash")
(curlet)))
; This is for demonstration:
(define *other*
(let ((one 1))
(define (anything . AB)
(format #t "~A" AB)
())
(curlet)))
; Works fine if looping with for-each
(for-each (lambda (N)
((*wtf* 'anything)
"any string"
(logior 42 (*other* 'one))))
'(ok fail))
(newline)
; -> ("any string" 43)("any string" 43)
; Works fine if not calling a C function
(map (lambda (N)
((*other* 'anything)
"any string"
(logior 42 (*other* 'one))))
'(ok fail))
(newline)
; -> ("any string" 43)("any string" 43)
; This combination fails:
; call a C function found in a let
; have one of its arguments be a simple call to logior (or some others)
; have one of logior's arguments be looked up in a (any) let.
; loop at least twice
;
; The first argument to the C function will be replaced by the first
; argument to logior on the second and subsequent loop iterations
(map (lambda (N)
((*wtf* 'anything)
"any string"
(logior 42 (*other* 'one))))
'(ok fail))
(newline)
; -> ("any string" 43)(42 43)
Matthew
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