Struct hash issues with string fields

[Ali Çehreli]

On 05/27/2012 04:22 AM, Andrej Mitrovic wrote:
> On 5/27/12, Ali Çehreli<acehreli at yahoo.com>  wrote:
>> On 05/26/2012 05:13 PM, Ali Çehreli wrote:
>>
>>   >  once you define toHash(), you
>>   >  must also define opCmp() and opEquals() that are all consistent with
>>   >  each other.
>>
>> Correction: opEquals() is only for potential optimizations. What is
>> needed alongside toHash() is just opCmp(), and the reason is to be able
>> to resolve hash collisions.
>
> Thanks! Is this documented somewhere on dlang.org?

Yes. It is under the "Using Structs or Unions as the KeyType" section of 
the As­so­cia­tive Ar­rays documentation:

   http://dlang.org/hash-map.html

It actually says "The implementation may use either opEquals or opCmp or 
both". So I guess opEquals() is still necessary for portability.

Ali

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