Re: [boost] [transact] transaction language macros (was: Re: [transact] code in sandbox)

Subject: Re: [boost] [transact] transaction language macros (was: Re: [transact] code in sandbox)
From: strasser_at_[hidden]
Date: 2010-02-19 16:40:01

2 corrections:

>> begin_transaction{
>>   try{
>>     //...
>>   }catch(boost::transact::isolation_exception & ex){
>>        // do something before retry
>>   }
>> }end_transaction;
>
> if we move the __control=0; from the catch(isolation_exception &)  
> clause up to the catch(...) one, the above use case seems OK.
> neither in the case that the whole transaction scope is exited by an  
> exception , nor in the case that the retry-loop is continued the  
> value of __control matters. it's only set to 0 for the "break out of  
> retry" case.

what I wrote here is nonsense. if the user "break"s in a self-defined  
catch(isolation_exception &) clause like you've shown above, the  
user's loop is affected. the value of __control is set correctly. if  
the user rethrows, the value doesn't matter.

>
>> As any macro in Boost.Transact must be prefixed with BOOST_TRANSACT, maybe
>> BOOST_TRANSACT_TRANSACTION/BOOST_TRANSACT_END could be more appropiated than
>> BOOST_TRANSACT_BEGIN_TRANSACTION/BOOST_TRANSACT_END_TRANSACTION
>
> I thought about that, but since there are now multiple macros I also  
> wanted to #define the lower case macros without prefix, if the user  
> chooses to include them.
> I'd find it slightly confusing that
>
> end_transaction
>
> is defined to
>
> BASIC_TRANSACT_END
>
> when "BASIC_TRANSACT_" is kind of the namespace of the macro.

...unless we wanted to make the keywords "begin", "retry" and "end".
I'm in favor if simple keywords, C++'s "try" and "catch" aren't very  
specific either. but unfortunately "begin" and "end" are used in STL  
containers.