Exponential operator

[Lars T. Kyllingstad]

Don wrote:
> Miles wrote:
>> Lars T. Kyllingstad wrote:
>>> Neither of the natural candidates, a^b and a**b, are an option, as they
>>> are, respectively, already taken and ambiguous.
>>
>> I think that a ** b can be used, is not ambiguous except for the
>> tokenizer of the language. It is the same difference you have with:
>>
>>   a ++ b  -> identifier 'a', unary operator '++', identifier 'b' (not
>> parseable)
>>
>>   a + + b  -> identifier 'a', binary operator '+', unary operator '+',
>> identifier 'b' (parseable)
>>
>> I don't know anyone who writes ** to mean multiplication and
>> dereference, except when obfuscating code. People usually prefer adding
>> a whitespace between both operators, for obvious readability purposes.
>>
>> I think it is perfectly reasonable to deprecate current usage of '**'
>> for the next release, and a few releases later, make '**' a new
>> operator. I doubt anyone would notice.
> 
> That doesn't work, because you still get new code being converted from 
> C. It can't look the same, but behave differently.
> 
>>
>> Other examples:
>>
>>   a-- - b
>>   a - --b
>>
>>   a && b
>>   a & &b
> 
> You didn't respond to my assertion: even if you _could_ do it, why would 
> you want to? ** sucks as an exponential operator. I dispute the 
> contention that ** is a natural choice. It comes from the same language 
> that brought you  IF X .NE. 2


I've been translating a lot of FORTRAN code to D lately, and it's 
amazing what one can get used to reading. Even X.NE.2. :) The worst part 
is translating 1-based array indexing to base 0 (it should be a simple 
transformation, but those old FORTRAN coders have made damn sure that 
isn't always the case...), and unraveling horrible spaghetti code like this:

   100 if(abserr.eq.oflow) go to 115
       if(ier+ierro.eq.0) go to 110
       if(ierro.eq.3) abserr = abserr+correc
       if(ier.eq.0) ier = 3
       if(result.ne.0.0d+00.and.area.ne.0.0d+00) go to 105
       if(abserr.gt.errsum) go to 115
       if(area.eq.0.0d+00) go to 130
       go to 110
   105 if(abserr/dabs(result).gt.errsum/dabs(area)) go to 115

In the end I just had to admit defeat and define a few labels...

-Lars