-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi! Am 10.02.12 09:39, schrieb Andrzej Krzemienski:
Sorry if this question is silly, but could you give me an example of where this deduction mechanism could be used?
The example I gave on comp.lang.c++.moderated is quite plain. The make_function is used to construct a class template instatiation. I think it compares to std::make_pair. I'll give another example below. What I'm trying to work with is a lazy computation. My class template Lazy<T> contains a variant over the type T and a function<T()> that can produce a value of that type. template<typename T> struct Lazy<T> { typedef T value_type; typedef function<value_type()> lazy_function_type; typedef variant<value_type, lazy_function_type> data_type; data_type data; //...ctors... value_type& get() { if(auto* const p = boost::get<lazy_function_type>(&data)) { data = (*p)(); } return boost::get<value_type>(data); } }; The real task now is to create a make_lazy() function that constructs a Lazy<T> from a lambda expression. Even when the target type is somehow known there is still an advantage in convenience, esp. with "auto var = make_lazy(...)." When calling template functions that take Lazy<T> for some T the type deduction would not work with just a lambda expression. I hope I could show to you that there is some usecase for make_function. Frank -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: keyserver x-hkp://pool.sks-keyservers.net iEYEARECAAYFAk82tzoACgkQhAOUmAZhnmrVYgCfUlN9FgIwgg0EqCbObBtNR2DR x0cAn14TOlJh5JotT7DI4Kv22uCP9+UJ =l6bv -----END PGP SIGNATURE-----