On 6/28/05, Arkadiy Vertleyb <vertleyb@hotmail.com> wrote:
"Alexander Nasonov" <alnsn-boost@yandex.ru> wrote
The following sentence in typeof.htm:
Other integral types, such as enums, need to be described explicitly with the BOOST_TYPEOF_INTEGRAL macro, like (BOOST_TYPEOF_INTEGRAL(MyEnum))
contrudicts with footnote in 3.9.1/7: 43) Therefore, enumerations (7.2) are not integral: however, enumerations can be promoted to int, unsigned int, long or unsigned long, as specified in 4.5
It should be easy to fix documentation. Not sure what to do with BOOST_TYPEOF_INTEGRAL, though.
BOOST_TYPEOF_INTEGRAL is used to denote template parameters which can be converted to compile-time integers, but, for some reason can't be recognized by the means of PP. Examples include integral types that are represented with more than two tokens (unsigned long int), enums, and dependent template parameters (template<class T, T n> class ...) It can also be used with any regular integral template parameters to avoid the "clever" PP code that is used to recognize it (which may be useful for porting). IOW, this maybe thouhgt of as if "unsigned int" is internally converted to BOOST_TYPEOF_INTEGRAL(unsigned int).
I am not sure how such a beast should be called. Maybe we should introduce a couple of synonyms, such as:
#define BOOST_TYPEOF_ENUM BOOST_TYPEOF_INTEGRAL #define BOOST_TYPEOF_DEPENDENT(x) BOOST_TYPEOF_INTEGRAL(P ## x)
It would also be possible to add a bit of syntactic sugar to allow: enum color {...}; template<color> some_class {}; template<template <typename,int> class T> struct tt_class {}; template<typename A1,T A2> struct dependent_class {}; BOOST_TYPEOF_REGISTER_TEMPLATE(some_class, (enum(color)) ); BOOST_TYPEOF_REGISTER_TEMPLATE(tt_class, (template((typename)(int))) ); BOOST_TYPEOF_REGISTER_TEMPLATE(dependent_class, (typename)(dependent(0)) ); Regards, Peder
Regards, Arkadiy
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