Re: [boost] Re: Formal Review: FOREACH macro

From: Stefan Strasser (sstrasser_at_[hidden])
Date: 2005-05-02 16:20:56

Eric Niebler schrieb:
>> I think it's not worth it here.
>> besides that it isn't a performance overhead on most containers you 
>> don't expect that from a keyword.
> 
> 
> 
> Huh, *I* would expect that from a keyword.

can you explain that?
why do expect a keyword to create temporaries and use outdated values?

(and what are the semantics in other languages which have that keyword?)

>>   std::string str="ab";
>>   foreach(char c,str){
>>     if(str.length() == 2) str+='c';
>>     std::cerr << c << std::endl;
>>   }
>>
>>
> 
> See the discussion about iterator invalidation. This code has undefined 
> behavior.

you're right
(even the SGI stl documentation admits that the std::string invalidation 
rules are strange).

-- 
Stefan Strasser