Lots of bool operations shouldn't compile

[Kyle Furlong]

Don Clugston wrote:
> Kyle Furlong wrote:
>> Don Clugston wrote:
>>> Thomas Kuehne wrote:
>>>> -----BEGIN PGP SIGNED MESSAGE-----
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>>>>
>>>> Don Clugston schrieb am 2006-02-28:
>>>>
>>>> [snip]
>>>>
>>>>> OK, there's another bug in there, comparing an int with an 
>>>>> imaginary real should also not be legal.
>>>>>
>>>>>      if (1 > -2i) { assert(0); }
>>>>>      if (1 > ireal.nan) { assert(0); }
>>>>>
>>>>> Reals and ireals cannot be compared. Ever.
>>>>
>>>> Sure you can. Floats and imaginary floats can both be implicitly 
>>>> promoted
>>>> to complex floats.
>>>
>>> That only gives you == and !=.
>>>
>>> <snip>
>>>> Thus
>>>>
>>>>>      if (1 > -2i) { assert(0); }
>>>>>      if (1 > ireal.nan) { assert(0); }
>>>>
>>>> are interpreted as
>>>>
>>>>>      if (1 + 0i > 0 - 2i) { ... }
>>>>>      if (1 + 0i > 0 + ireal.nan) { ... }
>>>
>>> Yes, but that still doesn't work, there's no > for complex numbers.
>>> Is  2 - 3i > 3 - 2i ?
>>
>> One could speak of their magnitudes, I suppose.
>>
>> creal i = 2 - 3i;
>> creal j = 3 - 2i;
>>
>> real i_m = sqrt(i * complexConjugate(i));
>> real j_m = sqrt(j * complexConjugate(j));
>>
>> but then I guess you are just comparing reals.
> 
> And then you have the problem (as in this case) that
> (i >= j) is true, and (i <= j) is true, but (i==j) is false.
> 
> Actually, though, you _could_ bring the NCEG operators into play, and
> define
> a >  b  as   abs(a) > abs(b)
> a >= b  as   abs(a) > abs(b) || a==b
> a !< b  as   abs(a) !< abs(b)
> a !<=b  as   abs(a) !< abs(b) && a!=b
> a <> b  as   abs(a) != abs(b)
> a !<>b  as   abs(a) == abs(b)
> a == b  as   a == b
> a <>=b  as   abs(a) <> abs(b) || a==b
> a!<>=b  as   abs(a) == abs(b) && a!=b
> 
> which would even work correctly with NANs.
> But there's no mathematical precedent for this, AFAIK.

As long as its well documented and doesn't introduce bugs, why not?