Re: Add corollary extension

[James Dennett <james dot dennett at gmail dot com>]

On Thu, Jun 28, 2012 at 12:39 PM, Rick Hodgin <foxmuldrster@yahoo.com> wrote:
>> Why do you want to bother with a non-standard,
>> unportable extension instead of just writing:
>>
>> inline bool isSystemClosed()
>> { return !isSystemOpen; }
>>
>> Which is simple, conventional, easy to understand
>> and portable.
>>
>> Or in C++ just define a suitable type, instead of
>> needing changes to the core language:
>>
>> struct inv_bool {
>> ? bool& b;
>> ? operator bool() const { return !b; }
>> };
>>
>> inv_bool isSystemClosed = { isSystemOpen };
>
> There are certain fundamentals in data processing. ?The inverse bool is one of them. ?Why not be able to reference it more naturally in code utilizing something the compiler already knows about and can wield effortlessly?
>
> I've thought more about the syntax, and I see this making more sense:
> bool isSystemOpen[!isSystemClosed];
>
> As the inverse bool relationship is fundamental in software, I hope this will become a C/C++ standard.

I really can't imagine that happening.  As the logical not operation
is fundamental, we already have notation for it.  Why would we add the
complexity of something that looks like a variable but acts like a
function?  In C++ you can already write
  auto isSystemOpen = [&isSystemClosed] { return !isSystemClosed; };
and then use isSystemOpen(), without doing violence to variable
notation.  You can obscure that behind a macro in your own code if you
wish, as in
  #define OPPOSITE(realVariable) (&realVariable] { return !realVariable; })
  auto isSystemOpen = OPPOSITE(isSystemClosed);
but wanting to make something that's a function look like a variable
isn't likely to get much traction in either language.

-- James