Scheme language standardization process
On 08/29/2011 03:47 PM, Alex Shinn wrote: > On Tue, Aug 30, 2011 at 3:26 AM, John Cowan<cowan@x> wrote: >> >> "It is an error" does not mean "an error is signalled". It's perfectly >> fine for existing or future Schemes to store or output an undefined >> value; it just isn't portable to do so. So it is not invasive and breaks >> nothing except user code like >> >> (define x (set! y 32)) >> >> which has no portable meaning in any case (it will not work in Racket, e.g.). > > Not true, as Eli pointed out. > > I'm unable to find a single implementation > which does _not_ return a single unspecified > value in these cases, despite the change in > R6RS. Kawa defines set! etc to return #!void which is defined to be same as (values). Kawa doesn't complain about (define x (set! y 32)) but it probably should. -- --Per Bothner per@x http://per.bothner.com/ _______________________________________________ Scheme-reports mailing list Scheme-reports@x http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports