unsigned policy (implicit conversions for complex?)

[Frits van Bommel]

Joel C. Salomon wrote:
> Walter Bright wrote:
>> Derek Parnell wrote:
>>> Characters are not numbers. 
>>
>> That's an enticing point of view, and it sounds good. But Pascal has 
>> that view, and my experience with it is it's one of the reasons Pascal 
>> sucks.
>>
>> Examples:
>>
>> 1) converting text <=> integers
>> 2) converting case
> 
> Neither are pointers numbers, but
>     &a - &b
> yields a usable number.  So long as
>     x += c - 'a'
> works, I don’t care if
>     'a' * '3'
> breaks.

Thank $DEITY. If nobody made this point before I read all of this 
subthread I would have to write a long post explaining this.

Let me reiterate that: characters are to integers as pointers are to 
integers.
The difference between two pointers is an integer, and you can add 
integers to pointers. These are the only arithmetic operations allowed 
on pointers.
The same should hold if you substitute 'character' for 'pointer' 
everywhere in previous two sentences.


Now, a short comment for each of the cases:

Walter Bright wrote:
 > Examples:
 >
 > 1) converting text <=> integers

I don't see any reason why disallowing conversions from characters to 
integers would disallow one to add or subtract integers from characters.
So (for c of type char/wchar/dchar) c - '0' can still be an integer, for 
example.
But it makes absolutely no sense to be able to say c + '0'. Or c * '0'.

 > 2) converting case

As above, (c - 'A') + 'a' can still be allowed. (c - 'A') is an integer, 
add 'a' to get a character again.

 > 3) doing compression/encryption code

These should probably use void[] for input and ubyte[] for output.

 > 4) using characters as indices (isspace() for example)

If you're using Unicode this is a bad idea anyway. Except perhaps if you 
use a sparce associative array, and then this isn't a problem anyway.

If you insist on using a regular array (and make sure the character 
value is suitably small) you don't necessarily have to use a cast, you 
can also subtract '\0' if you prefer.


Back to Joel:
>> 4) using characters as indices (isspace() for example)
> 
> Is there a way to declare the index type of an array?

Only if you use an associative array.