opPow, opDollar

[KennyTM~]

On Nov 8, 09 00:15, Robert Jacques wrote:
> 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") ∑;

Or

pure nothrow T ²(T)(T x) { return x*x; }
alias sqrt √;

:p

(OK ²(xxx) is still odd.)