Re: [Boost-users] [Proto] Extracting types of sub-expression in transform

Eric Niebler wrote:

I want to learn this stuff, but the references you've provided so far haven't helped. How badly do you want to see something like this in Boost? Badly enough to jump in and get your hands dirty with some code? Maybe you could help me to add two-level grammar support to Proto.

FWIW, there's an annex on this in the ISO EBNF documentation. Here's the final draft: http://www.cl.cam.ac.uk/~mgk25/iso-14977.pdf Annex A suggests how Extended BNF might be extended to define a two-level grammar. I've had interest on this when I came across that part. Nothing much there, just FYI... Regards, -- Joel de Guzman http://www.boostpro.com http://spirit.sf.net