opPow, opDollar

[Robert Jacques]

On Sat, 07 Nov 2009 10:48:11 -0500, KennyTM~ <kennytm at gmail.com> wrote:

> On Nov 7, 09 18:43, Don wrote:
>> Walter Bright wrote:
>>> Don wrote:
>>>> A little while ago I said I'd create a patch for ^^ as an
>>>> exponentiation. A couple of people had requested that I make a post
>>>> to the ng so they'd know when it happens. Here it is.
>>>>
>>>> This is opPow(), x ^^ y
>>>>
>>>> http://d.puremagic.com/issues/show_bug.cgi?id=3481
>>>
>>> I don't understand the rationale for an exponentiation operator. It
>>> isn't optimization, because pow() could become an intrinsic that the
>>> compiler knows about. pow() is well known, ^^ isn't. (Fortran uses **)
>>
>> It's primarily about syntax sugar: pow() is so ugly. In practice, the
>> most important case is squaring, which is an extremely common operation.
>> pow(xxx,2) is horribly ugly for something so fundamental. It's so ugly
>> that noone uses it: you always change it to xxx * xxx. But then, xxx
>> gets evaluated twice.
>>
>
> Nice. Meanwhile, I'd like an opSum() operator (∑ range) as well. It's  
> primarily about syntax sugar: reduce!("a+b")(range) is so ugly. In  
> practice, the most important case is the sum from 1 to n, which is an  
> extremely common operation. reduce!("a+b")(iota(1,n+1)) is horribly ugly  
> for something so fundamental. It's so ugly that noone uses it: you  
> always change it to n*(n+1)/2. But then, n gets evaluated twice.
>
>> Yes, ^^ hasn't been used for exponentiation before. Fortran used **
>> because it had such a limited character set, but it's not really a
>> natural choice; the more mathematically-oriented languages use ^.
>> Obviously C-family languages don't have that possibility.
>>
>

Well, since D supports unicode, you can always define: alias  
reduce!("a+b") ∑;