On Wednesday, January 25, 2012 08:20:02 Joel de Guzman wrote:
Now, what I advocate is exposing the typedef:
attribute_keyword< tag::severity > severity_type;
and letting the user create a local (function scope) object himself:
boost::log::severity_type severity;
The typing involved is the same. With namespace scope objects, the "best-practice" is for you to put these objects in a spacial namespace and hoist it into the client namespace using using declarations anyway (e.g.):
using boost::log::severity;
The compile time problem is very significant that in Spirit and indeed in Phoenix-3, we have special PP defines to disable the predefined objects (e.g.):
#define BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
Interesting, thanks for the info. But these keywords are to be user-defined and the whole point behind them is to reduce typing and simplify Boost.Log usage. For instance, I also plan to support this syntax for extracting an attribute value from a log record: optional< my_severity > sev = rec[severity]; Having to declare a local keyword variable for this seem inappropriate. But I can make the keyword creation optional by providing several macros for keyword registration - one that only defines the keyword type and another one that also creates the keyword. Also, I can put the declared keyword in a namespace and let the user decide whether he wants to import it by using declaration or not.