Küppers, Ben <ben.kuppers <at> logicacmg.com> writes:
I consider the scope guard to be a well-known and well-documented idiom and I fail to see what the ScopeExit library adds to it (or fail to be convinced by the arguments made in the alternative section of the help).
Scope guard is well-known because it had no competitor. I used to like it until I realised that scope guard is not good enough in archieving a strong exception guarantee. Scope guard bodies tend to be complex in many cases. E.g. they often have conditional or even a loop (for example, you count each successful push_back and then pop_back all inserted elements inside a rollback block). ScopeExit depends on non-standard typeof feauture and it couldn't be widely used before Boost.Typeof has been accepted. With a good promotion this library has a chance to become well-known too.
Rolling this functionality into a macro that makes the C++ syntax similar to D seems rather pointless and only contributes to a very unnatural C++ syntax.
It looks unfamiliar at present but lambda proposal for C++0x may change it: // N2329 syntax ScopeGuard g = <>(: ¤cy_rate_inserted, &commit, &rates, ¤cy) { if(currency_rate_inserted && !commit) rates.erase(currency); } which is closer to ScopeExit syntax than to ScopeGuard+Boost.Lambda. // ScopeExit BOOST_SCOPE_EXIT( (currency_rate_inserted)(commit)(rates)(currency) ) { if(currency_rate_inserted && !commit) rates.erase(currency); } BOOST_SCOPE_EXIT_END // ScopeGuard+Boost.Lambda ON_BLOCK_EXIT( if_(currency_rate_inserted && !_1) [ bind( static_cast< std::map<std::string,double>::size_type (std::map<std::string,double>::*)(std::string const&) >(&std::map<std::string,double>::erase) , &rates , currency ) ] , boost::cref(commit) ); -- Alexander