Steven Watanabe <watanabesj <at> gmail.com> writes:
Also, I need to be able to specify the name of the function somehow and I am not sure how this can be accomplished with that interface. Here's what I have right now:
...
So that
int BOOST_LOCAL_FUNCTION(name, (i)(j), (int x)(int y)) { //body here } BOOST_LOCAL_FUNCTION_END
expands to
int result_tag; typedef BOOST_TYPEOF(result_tag) result_type; typedef BOOST_TYPEOF(i) type_0; typedef BOOST_TYPEOF(j) type_1; typedef boost::tuple<type_0, type_1> tuple_type; typedef local_function<tuple_type, result_type(tuple_type, int x, int y)> function_type; function_type name(make_tuple(i, j)); { function_type* function_ptr = &name; struct body { result_type impl(tuple_type& args, int x, int y) { type_0& i = boost::get<0>(args); type_1 j = boost::get<1>(args); { //body here } } }; function_ptr->f = &body::impl; }
This is really impressive! I'd moved function arguments closer to the function name int BOOST_LOCAL_FUNCTION(name, (int x)(int y), (i)(j) ) Ideally, arguments should be listed naturally: int BOOST_LOCAL_FUNCTION(name, (int x, int y), (i)(j) ) but I don't see how to pass the args variable to body::impl.
Note that i and j are passed by value rather than by reference. Otherwise, it is not safe to have a copy of the function around after control leaves the scope it is defined in.
Passing by reference is often fine for ScopeExit but it's very dangerous for local functions. Optionally passing by reference would be a nice feature, though. -- Alexander