Re: [boost] Macros at namespace scope: trailing semicolon?

From: Andy Little (andy_at_[hidden])
Date: 2005-07-15 06:33:35

"Arkadiy Vertleyb" <vertleyb_at_[hidden]> wrote
> "Andy Little" <andy_at_[hidden]> wrote

>> Surely Typeof  is used in situations where  semicolon  not allowed:
>>
>> template<typename TL, typename TR>
>>     point<BOOST_TYPEOF_TPL(TL() + TR())>
>>     operator +( point<TL> const & lhs, vect<TR> const& rhs);
>
> No, what I actually mean is:
>
> BOOST_TYPEOF_REGISTER_TYPE(...)
> BOOST_TYPEOF_REGISTER_TEMPLATE(...)

Oops soory. However this identifies a point which I dont think has been made in
this discussion. A generic macro is just a shapeless blob standing in for some
text. Therefore I dont see it is possible to make general rules such as to
whether a trailing semicolon is included. There is simply not enough definition.
One would have to classify the *class* of macro rigorously (probably via the
grammar) first. eg is this macro representing  a typeid, an
assignment-expression etc. Isnt this  really what we are discussing ... fitting
a macro into the grammar of the language?  Identify the *class* of macro in the
grammar to identify whether  it is possible to use a particular macro in
situations where a semicolon is not required, or whether the semicolon is always
necessary, hence rightfully included as part of the macro.

regards
Andy Little