First Impressions

[Chad J]

Anders F Björklund wrote:
> Chad J > wrote:
> 
>> char[] data; 
> 
> 
>>   dchar opIndex( int index )
>>   {
>>     foreach( int i, dchar c; data )
>>     {
>>       if ( i == index )
>>         return c;
>>
>>       i++;
>>     }
>>   }
> 
> 
> This code probably does not work as you think it does...
> 
> If you loop through a char[] using dchars (with a foreach),
> then the int will get the codeunit index - *not* codepoint.
> (the ++ in your code above looks more like a typo though,
> since it needs to *either* foreach i, or do it "manually")
> 
> import std.stdio;
> void main()
> {
>    char[] str = "Björklund";
>    foreach(int i, dchar c; str)
>    {
>      writefln("%4d \\U%08X '%s'", i, c, ""d ~ c);
>    }
> }
> 
> Will print the following sequence:
> 
>    0 \U00000042 'B'
>    1 \U0000006A 'j'
>    2 \U000000F6 'ö'
>    4 \U00000072 'r'
>    5 \U0000006B 'k'
>    6 \U0000006C 'l'
>    7 \U00000075 'u'
>    8 \U0000006E 'n'
>    9 \U00000064 'd'
> 
> Notice how the non-ASCII character takes *two* code units ?
> (if you expect indexing to use characters, that'd be wrong)
> 
> More at http://prowiki.org/wiki4d/wiki.cgi?CharsAndStrs
> 
> --anders

ah.  And yep the i++ was a typo (oops).

So maybe something like:

   dchar opIndex( int index )
   {
     int i;
     foreach( dchar c; data )
     {
       if ( i == index )
         return c;

       i++;
     }
   }

The i is no longer the foreach's index, so the i++ isn't a typo anymore.

Thanks for the info.  I'll check out that faq a little later, gotta go.