[Cfp-interest 3251] Re: Lingering references to imaginary type

[Damian McGuckin]

Thanks Jim, I thought I had gone through Annex G to catch the last of 
those.

On Tue, 27 Aug 2024, Jim Thomas wrote:

> Below is a link to a draft proposal per action item:
>           Jim: Draft proposal to remove instances of imaginary
>       lingering in draft.
> 
> https://wiki.edg.com/pub/CFP/WebHome/C2Y proposal - lingering references to
> imaginary type-20240827.pdf

I do not want to pick at straws but in G.3.2#5,

 	return x + I * y

is perfectly legal as 7.3.1 says that I is equivalent to _Complex_I. 
(unless a programmer is crazy enough to redefine the macro I - uggh!)

I actually think that we could even say in 7.3.9.3#3

 	CMPLX(x, y) returns x + I * y

Because this is exactly what it does! Very succinct.

Note that we could be creating a rod for our own back (or that of somebody 
else if we are not around in 2029 or 2038 when IEEE 754 might or might not 
have complex arithmetic). I can already see a problem with the definition 
of the term "complex type" (which was hinted at by the mistake somebody 
else made in talking about "complex floating type" in paragraph 7.27#10 of 
the current document)

Note that my corrections address that mistake in 7.27#10 because there is 
no such that as a "complex floating type".

But they do not address the fundamental issue if we see imaginary types 
come back at a later date (if IEEE 754 precipitates that).  Note that when 
the C standard talks about "real types" now, it does so in the almost 
strict mathematical sense. When it currently talks about "complex types" 
it is normally talking about C types. But that is a whole new problem. To 
follow what the standard does for "real types", i.e. the standard floating 
types, decimal floating types, and integers, yes, integers, we would have 
to define "complex types" as a combination of only a single category

 	complex floating types

and change a gazillion places in the standard. Not a tiny task.

Then, complex types can retain its mathematical meaning. And at a later 
stage, if the C type "imaginary" makes a comeback, then we can add

 	imaginary floating types

to the concept of "complex types".

But changing the C standard to handle this very distant scenario is NOT 
worth it. It is happens post 2038, most of us won't have to worry about it 
as we will be long out of the picture and lying on a beach in retirmenet 
or otherwise.

- Damian