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1.57.0 beta 1 is now available
by Marshall Clow 30 Oct '14

30 Oct '14

Boost release 1.57.0 beta 1 is now available from SourceForge See http://sourceforge.net/projects/boost/files/boost-binaries/1.57.0.beta.1/ This release contains no new libraries. For details of what's in the release, see http://www.boost.org/users/history/version_1_57_0.html. Note that the links to files on this web page are for the final release - use the SourceForge link above to get the beta files. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team P.S. There are a couple of known problems with this beta: * There are problems building with MSVC 8.0 * There are some problems with range/detail/any_iterator.hpp. These will be fixed before the release.

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Re: [boost] Is there interest in a library for string-convertible enums?
by Felix Uhl 30 Oct '14

30 Oct '14

Artyom Tokmakov wrote: > Have you considered X-macro trick? Yes, and I heavily dislike the syntax. I played around with it a bit and it is absolutely not feasible for this use case. My goal is a simple, intuitive and easy to use syntax. With xmacros you’d have to define an enum in a separate file, Which only makes sense for really, really large enumerations.

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Re: [boost] Is there interest in a library for string-convertible enums?
by Felix Uhl 29 Oct '14

29 Oct '14

Artyom Tokmakov wrote: >In addition to various useful suggestions on the list, I would ask for >implementation to support (almost) any large number of enum elements >(enumerators) within enum declaration.: >I have ad-hoc implementation of my own which uses Boost.Proprocessor's >sequence to define enum elements. Then I can generate whatever >parser/printer/other code I want (I find that very useful). >There's a disadvantage, however: obvious limitation of max 256 >elements (at least, by default) coming from Boost.Preprocessor. And that’s where the problem lies. To enable large numbers of enum values, I’d have to find a solution without using Boost.PP. Without C++ introducing argument number based macro overloading, that is not possible, short of defining my own macro sequences for more than 256 elements, which I would like to avoid. I am still thankful that you asked for this, because it uncovered a huge implementation problem which induces enormous compilation overhead (1 minute for 48 enum values on my laptop). I will do my best to make the library comprehend large enums, but I can’t guarantee anything larger than 256. --- Felix Uhl

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Is there interest in a library for string-convertible enums?
by Felix Uhl 29 Oct '14

29 Oct '14

So far, the only way to convert an enumeration value to a string is a lot of boilerplate code consisting of switch case statements for every single possible value of the enum. I’ve written a small header-only library that uses Boost.Preprocessor and templates to ease the definition of named enumerations that are convertible to and from strings. Those can also be used with the std::cin and std::cout streams naturally, while maintaining all syntactic and semantic properties, regarding initialisation, assignment, type safety and conversion to underlying types. Currently, I am documenting the first version of the library to make it available on the Boost Library Incubator website, but I wanted to get some initial feedback from the developers mailing list, too. I would be glad to extend the library to a general extension of enumeration behaviour, like changing the generation of underlying values from a continuous increment to a continuous shift left by one, effectively making the underlying values binary flags. What features would you want from such a library? Is there even a chance that such a library would get included in boost (given that it satisfied the quality requirements), or is there too little interest in this functionality?

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Re: [boost] Is there interest in a library for string-convertible enums?
by Felix Uhl 29 Oct '14

29 Oct '14

Pieter wrote: > Are you aware of the earlier effort by Frank Laub? Frankly (no pun intended), I am not. It would be interesting to see how he has implemented that and what caveats his implementation has. --- Felix

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Re: [boost] Is there interest in a library for string-convertible enums?
by Felix Uhl 29 Oct '14

29 Oct '14

Jeffrey Bush wrote: > I have also offered a class for doing this as well, although it didn't draw > the interest that this one did. > Here was my attempt at it with a test/example class: > https://gist.github.com/coderforlife/6d8bac451d49dd1a0c81 Looks good to me, and seems to be quite close to what I aim at. But the definition seems very user unfriendly. Is it correct that you always have to declare enums in the public namespace? --- Felix

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Re: [boost] Is there interest in a library for string-convertible enums?
by Felix Uhl 29 Oct '14

29 Oct '14

Rob Stewart wrote: > You should not add features because someone on this list asked for them. > If you're not convinced of the utility of something, push back > to understand the request better. This sounds like advice I should follow. I tend to forget that I’m not writing for a specific client. Also, I noticed that the library has too much compile time overhead already, which should be fixed before introducing any additional ground-breaking features. So I’ve gone through the features suggested and ordered them by priority, perhaps the requesters of the following ones could answer my questions about them and specify why they think these features would be a good addition to the library: By Damien Buhl: - Adaptation of enums after declaration with something like BOOST_ADAPT_ENUM Is this really worth the effort? If somebody knows they want to string-convert an enum (or enum class), why would they not define it as one in the first place? Or is this about enumerations that are already defined by other libraries? Would it be ok to instead define a new enum that has the “to adapted” one as its underlying type and can thus be converted to and from it? There are implementational problems with offering both namespace independent definition of those enums and adaptability. By Gavin Lambert: - Specify custom and multiple strings In which use cases would this actually be beneficial for anyone? Could those use cases be solved by using custom char_traits or even custom string classes? - Specify different conversion tables for use in different contexts What do you exactly mean by that? Conversion to different string values? Conversion by different algorithms? Again, if you could answer those questions, it would really help evaluation. --- Felix

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[gsoc] Any interest in Google Code In?
by Niall Douglas 29 Oct '14

29 Oct '14

The application period for Google Code In 2015 has opened. This is a "tiny GSoC" programme for high school students where the tasks set might take the student three to five hours each. Stuff like writing documentation, improving unit testing, duplicating bug reports, making YouTube video tutorials, blogging about or writing an essay about getting a Boost development setup ready, even refactoring small segments of code if the student is up to it. The important part is the shortness of work item, and of course that you review it and give constructive feedback. More detail is at https://developers.google.com/open-source/gci/. Some example tasks from last year are at https://developers.google.com/open-source/gci/resources/example-tasks. Is there any interest from the Boost community in mentoring such high school student work? If so, now is the time to say. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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Re: [boost] Is there interest in a library for string-convertible enums?
by Artyom Tokmakov 29 Oct '14

29 Oct '14

> What features would you want from such a library? Hello, thanks for the proposal, it's very useful! In addition to various useful suggestions on the list, I would ask for implementation to support (almost) any large number of enum elements (enumerators) within enum declaration.: I have ad-hoc implementation of my own which uses Boost.Proprocessor's sequence to define enum elements. Then I can generate whatever parser/printer/other code I want (I find that very useful). There's a disadvantage, however: obvious limitation of max 256 elements (at least, by default) coming from Boost.Preprocessor. In fact, I hit some other limitations even before that. One of them was max 'if else' statements (I used them in parser implementation. Don't judge me, it was good enough!). When I fixed that, my VC compiler started complaining about some macro processor limitations around 220 enum elements (don't have details handy). Speed of parsing/printing implementation doesn't matter for me. PS: This is my first post in this DL, sorry if I broke some rules. -- Best regards, Artem Tokmakov

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Re: [boost] Is there interest in a library for string-convertible enums?
by Jeffrey Bush 29 Oct '14

29 Oct '14

> > So far, the only way to convert an enumeration value to a string is a lot > of boilerplate code consisting of switch case statements for every single > possible value of the enum. > > > I?ve written a small header-only library that uses Boost.Preprocessor and > templates to ease the definition of named enumerations that are convertible > to and from strings. Those can also be used with the std::cin and std::cout > streams naturally, while maintaining all syntactic and semantic properties, > regarding initialisation, assignment, type safety and conversion to > underlying types. > > > Currently, I am documenting the first version of the library to make it > available on the Boost Library Incubator website, but I wanted to get some > initial feedback from the developers mailing list, too. I would be glad to > extend the library to a general extension of enumeration behaviour, like > changing the generation of underlying values from a continuous increment to > a continuous shift left by one, effectively making the underlying values > binary flags. > > > What features would you want from such a library? Is there even a chance > that such a library would get included in boost (given that it satisfied > the quality requirements), or is there too little interest in this > functionality? > I have also offered a class for doing this as well, although it didn't draw the interest that this one did. Here was my attempt at it with a test/example class: https://gist.github.com/coderforlife/6d8bac451d49dd1a0c81 Supports value to string and string to value, including multiple values with | between them, meaning all combinations can be round-tripped. Supports default power-of-two values and custom values, listing all valid values (as enum types, but each is easily convertible to integral and string values), Although you cannot specify custom string names for an enum value that is not the "STRINGIZE" name, however you can choose to have multiple enum entries with the same value and different names. Jeff

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