Re: [boost] interest in a flag library

Right now my code provide the "+" and the "-" operators to set or reset flags. Anyway, I see no problem in adding some named function for those who prefer using them. Masse Nicolas. Le ven. 26 oct. 2018 à 09:35, Andrzej Krzemienski via Boost < boost@lists.boost.org> a écrit :

czw., 25 paź 2018 o 23:28 Masse Nicolas via Boost napisał(a):

...

Hi all,

This is the first time I post on this mailing list :). I'm posting because i'd like to know if people would be interested in a library to treat enum types as flags. I find that's something which is lacking in the language since the introduction of strongly typed enums, and I've since written some code in order to do this. So far I've seen some discussion on this mailing list about that, but it doesn't seems that any library have been written yet. So do you think it is worth the effort of porting and documenting my code so that it can integrated into boost, or not?

Hi. I would use a type-safe library for flags. I am missing one today. However, given that you provide your own type (which is good IMO), I would expect a different interface that reflects the meaning more directly. I consider bit-wise operations to be a hack rather than a proper solution. Expression `flags & Flags::EXEC` is quite idiomatic, but when I want to reset a flag, I have to write `flag &=~ Flag::EXEC` (which I call an 'oil lamp' operator), which is difficult to understand and likely to get wrong. (In fact, I am not sure I got it right in this example.)

I would rather expect an interface using named functions or indexing operator:

``` if (!flags[Flag::READ]) flags.reset(Flag::EXEC); ```

Regards, &rzej;

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