Re: [boost] [TypeIndex] Peer review period for library acceptance begins, ending Thurs 21st Nov

16 Nov 2013

      2013/11/16 Mathieu Champlon 
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On 16/11/2013 16:58, Antony Polukhin wrote:
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2013/11/16 Mathieu Champlon 
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(as
opposed to it's real type) could sometimes prove useful ?
Could it be worth adding a function in TypeIndex ?
This is a very very common use case in Boost and widely used technique
in
Do you think getting the type info of the "current" type of a variable
libraries that use type erasure. Examples are Boost.Function, Boost.Any,
Boost,Graph, Boost.Math and others...
Such function is already in TypeIndex library, see boost::type_info<T>().
Yes, but I meant given :
#define SOME_MACRO_IN_MY_LIBRARY( variable ) do_something_complicated_
requiring_type_info_of_type_of_variable
I cannot use boost::type_info<T>() easily can I ?
Granted I could do boost::type_info< BOOST_TYPEOF( variable ) >() but
that's a bit cumbersome compared to for instance a simple boost::type_info(
variable ).
Sorry, I meant boost::type_id (
http://apolukhin.github.io/type_index/boost/type_id.html)

Well, usually you have the type of the variable nearby, and can use it in
type_id<T>:

template <class T>
void operator()(const T& var) {
 type_id<T>(); // no need in  type_id(var);
}

...

int i;

type_id<int>() // no need in  type_id(i);

Cases when it is hard to detect variable type are rare in Boost and I do
not really wish to produce many trivial functions and make the library
heavier.
Anyway, user can always write such function in half a minute:

tempalte <class T>
inline const boost::type_info& my_type_id(const T&) {
    return boost::type_id<T>();
}

-- 
Best regards,
Antony Polukhin