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March 2010

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[boost] [log] Boost.Log formal review result
by Vladimir Prus 24 Mar '10

24 Mar '10

First of all, I would like to thank Andrey for this submission and the active discussion during the review. I also would like to thank everybody who participated in the review. The comments on the library were generally positive. Several reviewers have tried it in practical projects already, and found it superior to other libraries. It clearly will benefit the users of Boost right away. Therefore, the library is accepted. Congratulations, Andrey! On the other hand, some concerns about the ease of use and performance and implementation details were raised. Of those, some can be easily addressed as part of normal maintenance, while some seem to require significant rework and may change the library quite consirably. Therefore, the library is accepted subject to several conditions -- listed below under "Critical issues". Because the changes can be large, I think a mini-require is required when those issues are addressed. To avoid delays, it's probably not necessary to formally schedule and conduct a mini- review -- just posting a email asking for discussion will be sufficient. Statistics ========== There were roughly 300 emails during formal review (I have a mbox archive if anybody needs it). The following persons submitted a review with a vote. Some of votes are "provisional", this is not reflected below, but affects the list of critical issues below. - Boris Schaeling (yes) - Roland Bock (yes) - Ralf Globisch (yes) - Sean Chittenden (yes) - Darryl Green (no) - Tom Brinkman (no) - Barend (yes) - Sam Gundry (yes) - Vicente Botet (yes) - Robert Stewart (yes) - Alexander Arhipenko (yes) - "M-Square" (yes) Critical issues =============== These issues must be addressed, and be passed through informal mini- review, before the library can be added to SVN. - It appears that the 'trivial' logging is not sufficiently good to just take and use. The library should provide an out-of-the-box mechanism that: - supports channel/severity attributes, without creating new logger for each severity. It also should be possible to filter out specific channel by essentially poking at some "map", and without manually composing a new filter that checks for a set of allowed channels sequentally. I believe that at least Christian, Roland, Robert and myself requested this. - has no observable effect on compile time. One second (or more) that trivial.hpp imposes is not acceptable. - outputs to console by default, but permits changing that - outputs only component/severity/message by default, but probably permits changing that. - By default, the library should try hard to continue working no matter what errors happen during processign a log record -- including things like invalid attribute names or types, or other exceptions. - The library should not reinvent wheels. In particular, custom implementations of TSS and RW mutex seems like a very bad idea. Use of a custom lambda implementation was pointed by many as not great -- we already have a couple, so let's not add more to the mix. - Library interface is too geared towards lambda. In particular, implementing formatters/filters as free-standing functions appears to require considerably more code. In particular, it should be possible to access an attribute using a single function call. Also, logging::extract taking a lambda for callback complicates matters, it's desirable to have a more direct variant. Important issues ================ These issues are important enough to be mentioned here, but can be addressed as convenient. - The reported run-time performance can be improved. In particular the performance with date attributes seems scary and 2x slowdown relative to some other library in the 'most records are filtered out' case is also concerning. - I don't think it was satisfactory explained why 'attr' exists in two namespaces, as opposed to being a single type that is used for both formatting and filtering. Other notes =========== These issues seem important and should be considered, but might not even be fixable within the current design. - Several reviewers said the library is "too flexible" and this makes it harder to understand. Probably nothing can be done about that at this point, but interesting data point notwithstanding. - It was suggested that the library include an API that another Boost log may use in a way that permits plugging another logging library should end user of a Boost so desire. This seems a good idea, but I think it's up to Andrey to implement such API or not. - Alternative design approaches were proposed, in particular (i) permitting user log records and templating/basing other components on a user- defined record type and (ii) using compile-time indexing to access attributes. Also, it was proposed that named parameters not be necessary to use the library, and a more conventional interface be available. It does not seem that implementing those suggestions is fully possible without writing a different library from scratch, so it's up to Andrey to consider those proposals. - It was suggested to use newer Spirit to address poor compile times for the library itself. Thanks, Volodya _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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[Review] The review of the ITL library ends today, March 7th
by Hartmut Kaiser 07 Mar '10

07 Mar '10

Hey all, The review of Joachim Faulhabers ITL library ends today, March 7th 2010. Please get your reviews in today or get in contact with me to agree on some offline schedule. Regards Hartmut Review Manager --------------- Meet me at BoostCon www.boostcon.com

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