Optimizing Immutable and Purity

Andrei Alexandrescu SeeWebsiteForEmail at erdani.org
Tue Dec 23 23:02:35 PST 2008


Walter Bright wrote:
> Andrei Alexandrescu wrote:
>> Bill Baxter wrote:
>>> On Tue, Dec 23, 2008 at 11:30 AM, Jerry Quinn <jlquinn at optonline.net> 
>>> wrote:
>>>> This was an interesting read.  It would be nice to see a discussion 
>>>> of how const is going to fit in in terms of optimization potential, 
>>>> since you can always cast it away.
>>>
>>> It's basically useless for optimizations I think.
>>> Even if the view of the data you have is const, someone else might
>>> have a non-const view of the same data.
>>> So for instance, if you call any function, your "const" data could
>>> have been changed via non-const global pointers to the same data.
>>>
>>> --bb
>>
>> Const is still useful because inside a function you know for sure that 
>> another thread can't modify the data.
> 
> I think you meant immutable.

I meant const.

Andrei



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