lumiera_/research/try.cpp

116 lines
3.5 KiB
C++

/* try.cpp - for trying out some language features....
* scons will create the binary bin/try
*
*/
// 8/07 - how to control NOBUG??
// execute with NOBUG_LOG='ttt:TRACE' bin/try
// 1/08 - working out a static initialisation problem for Visitor (Tag creation)
// 1/08 - check 64bit longs
// 4/08 - comparison operators on shared_ptr<Asset>
// 4/08 - conversions on the value_type used for boost::any
// 5/08 - how to guard a downcasting access, so it is compiled in only if the involved types are convertible
// 7/08 - combining partial specialisation and subclasses
// 10/8 - abusing the STL containers to hold noncopyable values
// 6/09 - investigating how to build a mixin template providing an operator bool()
// 12/9 - tracking down a strange "warning: type qualifiers ignored on function return type"
// 1/10 - can we determine at compile time the presence of a certain function (for duck-typing)?
// 4/10 - pretty printing STL containers with python enabled GDB?
// 1/11 - exploring numeric limits
// 1/11 - integer floor and wrap operation(s)
// 1/11 - how to fetch the path of the own executable -- at least under Linux?
// 10/11 - simple demo using a pointer and a struct
// 11/11 - using the boost random number generator(s)
// 12/11 - how to detect if string conversion is possible?
// 1/12 - is partial application of member functions possible?
// 5/14 - c++11 transition: detect empty function object
// 7/14 - c++11 transition: std hash function vs. boost hash
// 9/14 - variadic templates and perfect forwarding
// 11/14 - pointer to member functions and name mangling
// 8/15 - Segfault when loading into GDB (on Debian/Jessie 64bit
// 8/15 - generalising the Variant::Visitor
// 1/16 - generic to-string conversion for ostream
// 1/16 - build tuple from runtime-typed variant container
// 3/17 - generic function signature traits, including support for Lambdas
// 9/17 - manipulate variadic templates to treat varargs in several chunks
// 11/17 - metaprogramming to detect the presence of extension points
// 11/17 - detect generic lambda
// 12/17 - investigate SFINAE failure. Reason was indirect use while in template instantiation
// 03/18 - Dependency Injection / Singleton initialisation / double checked locking
/** @file try.cpp
** Rework of the template lib::Depend for singleton and service access.
*/
typedef unsigned int uint;
#include "lib/format-cout.hpp"
#include "lib/depend.hpp"
#include "lib/depend2.hpp"
//#include "lib/meta/util.hpp"
#include "lib/util.hpp"
//#include <vector>
#define SHOW_TYPE(_TY_) \
cout << "typeof( " << STRINGIFY(_TY_) << " )= " << lib::meta::typeStr<_TY_>() <<endl;
#define SHOW_EXPR(_XX_) \
cout << "Probe " << STRINGIFY(_XX_) << " ? = " << _XX_ <<endl;
using lib::ClassLock;
template<class SRV>
class DependencyFactory
{
public:
static void
build (SRV*& instance)
{
UNIMPLEMENTED ("how to access the per-type factory");
}
};
template<class SRV>
class DependInject;
template<class SRV>
class Depend
{
static SRV* instance;
friend class DependInject<SRV>;
public:
SRV&
operator() ()
{
if (!instance)
{
ClassLock<SRV> guard;
if (!instance)
DependencyFactory<SRV>::build (instance);
}
ENSURE (instance);
return *instance;
}
};
template<class SRV>
SRV* Depend<SRV>::instance;
int
main (int, char**)
{
cout << "\n.gulp.\n";
return 0;
}