Wht std.complex is needed?

[Steven Schveighoffer]

On Mon, 06 Apr 2009 09:50:35 -0400, Don <nospam at nospam.com> wrote:

> Steven Schveighoffer wrote:
>> On Mon, 06 Apr 2009 08:36:18 -0400, Don <nospam at nospam.com> wrote:
>>
>>> Sam Hu wrote:
>>>> Thank you!
>>>> Anothe silly question then:What's the disadvantage to have the  
>>>> built-in type of i-type?
>>>>  Regards,
>>>> Sam
>>>
>>> It's a very nasty type. It supports *, but isn't closed under *.
>>> Which is really annoying for generic programming.
>>>
>>> idouble x = 2i;
>>> x *= x; // oops, this isn't imaginary. (BTW this currently compiles  
>>> :o).
>>  This may be a dumb question, but aren't all real numbers also  
>> technically imaginary numbers with a 0i term?  that is, I would expect  
>> the above to evaluate to:
>>  -4 + 0i
>>  Which I would view as an imaginary number.  Am I completely wrong here?
>
> It's a complex number.
> (real OP real OP real) is real.
> (complex OP complex OP complex) is complex.
> BUT
> (imaginary OP imaginary OP imaginary) is imaginary, or real, or complex.

Yes, I meant to say complex, sorry.

Turns out I was not reading fully the previous posts.  I was not aware  
that there were two separate types for complex and imaginary.  I thought  
idouble was a complex number.

That's kind of... um weird?  Why do you need an imaginary AND a complex  
type?  Wouldn't just a complex type suffice?

Anyway, don't mind me, I just was confused.

-Steve