New map[] directive to augment qi::symbols when doing binary parsing

[oakad@…]

qi::symbols is an exceptionally useful parser, but it is strongly tied to character strings as its input type. When doing binary parsing, one of the common tasks is de-serializing objects from the binary stream, an activity which can strongly benefit from Nabialek trick (​http://boost-spirit.com/home/articles/qi-example/nabialek-trick/). Another common use case are extensible enum types, a feat which is somewhat cumbersome to handle with attribute transformations.

This is my first attempt at implementing a qi directive, so it's probably far from perfect. One of the immediate shortcomings I want to resolve is direct dependency on std::map which is also passed by value between instances.

The implementation and a short example demonstrating Nabialek trick is attached.

[oakad@…]

Implementation of the map[] directive in the repository::qi namespace

[oakad@…]

Example showing use of map[] to implement Nabialek trick

[Joel de Guzman]

That's very interesting!

We deal with feature submissions like this through the Spirit mailing list. I suggest you post a message there.

[oakad@…]

Replying to djowel:

We deal with feature submissions like this through the Spirit mailing list. I suggest you post a message there.

Of course I posted a message there, with a link here. But I suppose, ticket is a good place to keep everything related together. Or isn't it?

[Joel de Guzman]

Yes, this is good.