[boost] [spirit] trunk: circular dependency parse <-> construct <-> assign_to (?)

From: troy d. straszheim (troy_at_[hidden])
Date: 2008-05-29 06:41:39

Hey Hartmut, Joel,

I started playing with spirit-2/lex (on the trunk), specifically examples/lex/example4.cpp, thought
I'd try to parse some python.  I've hit an error that was already asked about a month or so ago.
It appears to be because this guy:

    http://svn.boost.org/trac/boost/browser/trunk/boost/spirit/home/qi/detail/assign_to.hpp

doesn't have 'construct' overloads for various types (conversion to unsigned is the one
that comes up in the example).  I dug around and found construct.hpp,

    http://svn.boost.org/trac/boost/browser/trunk/boost/spirit/home/qi/detail/construct.hpp

which does have them, but they forward to parse(), using proto placeholders from over in
support/placeholders.hpp.  This ends up coming round again to assign_to.

At this point I can't decide whether this is going to be detangleable or not.
I thought I'd ask for some hints on what things are supposed to look
like in the end, if so.   In any event, the code is absolutely fascinating.  Time well spent.

Thanks,

-t