On Thu, Nov 3, 2011 at 11:05 AM, Lorenzo Caminiti <lorcaminiti@gmail.com>wrote:
On Wed, Nov 2, 2011 at 6:46 PM, Jeffrey Lee Hellrung, Jr. <jeffrey.hellrung@gmail.com> wrote:
On Wed, Nov 2, 2011 at 2:00 PM, Lorenzo Caminiti <lorcaminiti@gmail.com wrote:
[...]
A couple more things:
1) I thing that BOOST_PARAMETER_TEMPLATE_KEYWORD(ClassType) macro should define a symbol _ClassType to be used for the named parameter so to be consistent with the BOOST_PARAMETER_NAME(x) which defined _x to be used for the named function parameter. However, ClassType is defined without the leading _. What is the reason for this asymmetry?
The fact that each keyword is used in different contexts is enough justification for me to explain the asymmetry.
I gathered the leading underscored prepended to function parameter keywords was motivated by a desire to prevent shadowing bugs (as per the rationale given in the documentation, if I remember correctly). No such problem arises with template parameter keywords, so the only justification I can think of to prepend template parameter keywords with an underscore is because that's what's done with function parameter keywords, which seems kind of weak.
Yes but these all sound like implementation reasons to me. If the parameter name keywords need the leading _ for functions, as a library users I'd expect the template parameters to follow the same convention. Why should a user expect template parameter name keywords to follow a different convention than function parameter name keywords?
Well, they have different syntax as well, i.e., "_keyword = value" vs "keyword< value >" (I guess that's also technically an implementation detail...). My point being, function parameter keyword syntax and template parameter keyword syntax differ, so I don't think it's too onerous for the naming conventions to differ as well. But I see your point, and it probably could've easily gone the other way; honestly, I don't think the argument either way is particularly strong, and by now I'm used to the differing naming convention, so *I* am willing to accept that "this is just the way it is". That's not really suppose to convince *you*, though :) - Jeff