On Thu, Apr 4, 2019 at 11:41 AM megane wrote:
The R5RS says (1.3.2) that the value of an expression with undefined
> (actually "unspecified") value has to be a valid scheme value
> ("object"), and it's up to the implementation what that value is.
That's true. But a violation of syntax, which
> > Once you give a fixed meaning, even by doing an optimization based
> > on this meaning, users _will_ start to rely on it. At that stage it isn't
> > undefined anymore.
>
> There's two ways I can think of getting warnings, then.
>
> a) Easy version. Randomly choose true or false at each if.
megane writes:
> felix.winkelm...@bevuta.com writes:
>
>>>
>>> Nothing changes if we statically assign these values, the user still
>>> cannot rely on undefined to be either true or false.
>>
>> Once you give a fixed meaning, even by doing an optimization based
>> on this meaning, users _will_
felix.winkelm...@bevuta.com writes:
>>
>> Nothing changes if we statically assign these values, the user still
>> cannot rely on undefined to be either true or false.
>
> Once you give a fixed meaning, even by doing an optimization based
> on this meaning, users _will_ start to rely on it. At
>
> Nothing changes if we statically assign these values, the user still
> cannot rely on undefined to be either true or false.
Once you give a fixed meaning, even by doing an optimization based
on this meaning, users _will_ start to rely on it. At that stage it isn't
undefined anymore.
> >
felix.winkelm...@bevuta.com writes:
>> > No, but it could, depending on some arcane optimization that someone
>> > may implement in the future (or not). It's simply open to the
>> > implementation.
>> >
>>
>> There's the possiblity of documenting this optimization:
>>
>> "If the expression's
> > No, but it could, depending on some arcane optimization that someone
> > may implement in the future (or not). It's simply open to the
> > implementation.
> >
>
> There's the possiblity of documenting this optimization:
>
> "If the expression's value can be determined statically to be
megane writes:
> felix.winkelm...@bevuta.com writes:
>
>>> >> Based on my limited observations (##core#undefined) will always have
>>> >> the value 30L at runtime. This is not equal to 6L (or #f). Therefore
>>> >> an undefined value in conditional test will always cause the true
>>> >> branch
felix.winkelm...@bevuta.com writes:
>> >> Based on my limited observations (##core#undefined) will always have
>> >> the value 30L at runtime. This is not equal to 6L (or #f). Therefore
>> >> an undefined value in conditional test will always cause the true
>> >> branch to be chosen.
>> >
>> >
