opPow, opDollar

[Tim Matthews]

Walter Bright wrote:
> Andrei Alexandrescu wrote:
>> In order for everyone to air an informed opinion, a related question 
>> is: will loop fusion be allowed with function calls?
>>
>> Loop fusion currently only works with operators, and adding ^^ would 
>> allow:
>>
>> a[] = b[] ^^ 3;
>>
>> But with pow you can't do that:
>>
>> a[] = pow(b[], 3);
>>
>>
>> Andrei
>>
>> P.S. FWIW, I'm ambivalent on the issue; if functions were allowed for 
>> automatic loop fusion that would tilt my opinion in disfavor of ^^, 
>> and if not, it would tilt my opinion in favor of ^^.
> 
> 
> I don't think this is a valid argument for making pow() an operator, 
> because what about sin()? cos()? It's all the same issue, and they all 
> can't be operators.

Exponentiation, like addition, multiplication etc.. can be used multiple 
times in an expression at the same scope:

a + b + c

a * b * c

a ^^ b ^^ c

xor, sin, cos are only binary & unary operations. I think that is a good 
enough argument for which deserves operator over long function name but 
unlike the others, exponentiation is right associative so this should 
mean the same as:

a ^^ (b ^^ c)

This may also reduce the likely hood of bugs due to mathematical 
formulas being expressed incorrectly. It is far too easy to accidentally 
write:

a ^^ b ^^ c

as

pow(pow(a,b),c)

This one operator would really help D be accepted into the mathematical 
world.