D versus Objective C Comparison

[Chris R Miller]

Sean Kelly wrote:
> Chris R Miller wrote:
>>
>> ===== Short Story =====
>>
>> I needed to search through a String (NSString) specifically to know 
>> whether a character at a specific index is any one of a given set of 
>> characters.  Rather than subclass NSString, I decided to make a category:
>  > [snip]
> 
> Won't all of this be solved by the planned D2 feature of making these 
> operations synonymous for all types?
> 
> void fn(T val);
> T t;
> fn(t);
> t.fn();
> 
> Or are you saying that these added functions can actually access private 
> data in the class?

Yes, they can access private data.  I see how this could be both a 
feature and a potential hazard.  Then again, do you not need to be 
careful when subclassing things in Java-style OO languages?  Otherwise 
you can very easily mire yourself in a world of objects that end up 
hindering more than helping.

And just to prove D's potency, the very algorithm I used was stolen from 
something I wrote in D not long ago:

====== DuffsDevice.d ======

module duffsdevice;

import tango.io.Stdout;

/// tells if anything in the contents of arr1 are present in arr2
/// uses type implicit opCmp for comparison
bool hasAnyOf(T)(T[] arr1,T[] arr2){
     T[] small,large;
     if(arr1.length>arr2.length){
         large=arr1;small=arr2;
     }else{
         large=arr2;small=arr1;
     }
     int lp,rm=large.length%10;
     foreach(T t;small){
         lp=(large.length-1)/10;
         switch(rm){
             case 0: do{
                         if(t==large[lp*10+9]) return true;
             case 9:     if(t==large[lp*10+8]) return true;
             case 8:     if(t==large[lp*10+7]) return true;
             case 7:     if(t==large[lp*10+6]) return true;
             case 6:     if(t==large[lp*10+5]) return true;
             case 5:     if(t==large[lp*10+4]) return true;
             case 4:     if(t==large[lp*10+3]) return true;
             case 3:     if(t==large[lp*10+2]) return true;
             case 2:     if(t==large[lp*10+1]) return true;
             case 1:     if(t==large[lp*10  ]) return true;
                     }while(0<--lp);
                 break;
         }
     }
     return false;
}

void main(char[][] argc) {
     if(argc.length>2) {
         Stdout("argc[0]=={}",argc[1]).newline;
         Stdout("argc[1]=={}",argc[2]).newline;
         Stdout("hasAnyOf!(char[])(argc[0],argc[1])=={}",
                hasAnyOf!(char)(argc[1],argc[2])).newline;
     }
}

====== EOF ======

Personally I prefer the D to the Objective-C implementation.