Felix <pfr6rs_at_pnkfx.org> writes:
> Or are you implying that R6RS would also be changed so that everywhere
> we currently see "the value returned by foo is the unspeciifed value"
> we would instead see something to the effect of "the values returned
> by foo are indistinguishable from those that would be returned by an
> invocation of the procedure named unspecified to the same
> continuation" ?
No. I'm saying that the unspecified procedure returns an unspecified
number of unspecified values, possibly a different number of different
values each time around. By analogy, the return value(s) of
procedures like `vector-set!' would also be specified this way, but as
no relationship between the return values of different invocations of
`unspecified' exists, no such relationship between the return values
of `unspecified' and those of `vector-set!' exists, either.
The usefulness of providing `unspecified' in the report is that it
allows a programmer to say "I don't want to specify the return values
in this case", where often #t or #f or '() or the unspecific value
mentioned in R5RS is returned inadvertently, inviting clients to rely
on those values.
--
Cheers =8-} Mike
Friede, V?lkerverst?ndigung und ?berhaupt blabla
Received on Fri Oct 06 2006 - 10:33:10 UTC