Andy Wingo <wi...@pobox.com> writes:
> On Mon 29 Jun 2009 23:44, Neil Jerram <n...@ossau.uklinux.net> writes:
>
>> Andy Wingo <wi...@pobox.com> writes:
>>
>>> scheme@(guile-user)> (if %nil 1 2)
>>> 1
>>>
>>> #define scm_is_false(x) (scm_is_eq ((x), SCM_BOOL_F) || SCM_NILP (x))
>
>> Seems wrong to me. In Scheme #f should be the only false value.
>> What's the argument for %nil being false in Scheme code?
>
> I thought the original plan regarding %nil and #f and '() was that %nil
> wasn't supposed to be seen normally from Scheme, and for that reason
> (and (null? %nil) (not %nil)) would not be a problem.
>
> Guile has treated %nil as false for quite some time:
>
> scheme@(guile-user)> ,o interp #t
> scheme@(guile-user)> (if %nil 1 2)
> $1 = 2
I'm sorry... you're completely right. Brain storm on my part.
But then I don't understand the cause of your suggestion. Is it that
master has somehow regressed, so as to cause (if %nil 1 2) => 1 ?
Neil
