unsigned policy (implicit conversions for complex?)

[Derek Parnell]

On Mon, 12 Feb 2007 18:14:50 -0800, Andrei Alexandrescu (See Website For
Email) wrote:

> Derek Parnell wrote:
>> On Mon, 12 Feb 2007 16:03:14 -0800, Andrei Alexandrescu (See Website For
>> Email) wrote:
>> 
>>> http://erdani.org/d-implicit-conversions.pdf
>>  
>>> Did I forget something?
>> 
>> Characters are not numbers. 
> 
> http://www.digitalmars.com/d/type.html specifies they are "unsigned" and 
> also the number of bits. Their default initial value is written in hex. 
> This made me assume that they can be treated as numbers.

I was trying not to confuse implementation with theory. D implements
characters using unsigned integers, but as they are not semantically
numbers, it makes no sense to do many numerical operations on characters;
such as adding or multiplying them. To allow them to be /implicitly/
converted to integers may lead to subtle bugs, as the compiler will miss
semantically incorrect usage.

  int add(int a, int b)
  {
       return a + b;
  }

  int d = add('a', 'z');  // Should not match signature, but does.


-- 
Derek
(skype: derek.j.parnell)
Melbourne, Australia
"Justice for David Hicks!"
13/02/2007 1:49:57 PM