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new explicit template argument specification workaround for FnDispatcher::Add

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git-svn-id: svn://svn.code.sf.net/p/loki-lib/code/trunk@126 7ec92016-0320-0410-acc4-a06ded1c099a
This commit is contained in:
humesikkins 2003-03-21 16:54:35 +00:00
parent 3419c5b069
commit 31b1b37ee9
1 changed files with 60 additions and 12 deletions
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70
MSVC/1200/MultiMethods.h
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@ -13,23 +13,24 @@
// without express or implied warranty.
////////////////////////////////////////////////////////////////////////////////
// Last update: Mar 20, 2003
// Interface change for FnDispatcher::Add:
// The trampoline-Version of FnDispatcher::Add needs explicit template
// argument specification for type and non-type parameters. Unfortunately
// all workarounds used so far failed for this member-function.
// Therefore I need to use a new one which leads to another interface change:
// Example (see "Modern C++ Design" Section 11.6)
// ----------------------------------------------
// Using the original one writes:
// Last update: Mar 21, 2003
// Added a new explicit template argument specification workaround for
// FnDispatcher::Add which is more compliant with other
// explicit template argument specification workarounds used in this port.
//
// Example usage:
// --------------
// Using the original library one writes:
// typedef FnDispatcher<Shape> Dispatcher;
// void Hatch(Rectangle& lhs, Poly& rhs) {...}
//
// Dispatcher dis;
// disp.Add<Rectangle, Poly, &Hatch>();
//
// Using this port the example becomes:
// Dispatcher::AddI<Rectangle, Poly, &Hatch>()(dis);
// Using this port the example either becomes:
// dis.Add(Dispatcher::Add<Rectangle, Poly, &Hatch>());
// or alternatively
// Dispatcher::AddI<Rectangle, Poly, &Hatch>()(dis);
//
// All dispatchers now have void as default value for return types.
// All dispatchers now support void as return type.
@ -554,6 +555,51 @@ namespace Private
}
// two different workarounds for FnDispatcher::Add
// Using the first one writes:
// DisType dispatcher;
// dispatcher.Add(DisType::Etas<SomeLhs, SomeRhs, &AFunc>());
// using the second workaround the call becomes:
// DisType dispatcher;
// DisTyp::AddI<SomeLhs, SomeRhs, &AFunc>()(dispatcher);
// Helper-class for the first workaround.
// When calling FnDispatcher::Add provide an object of this type
// as argument.
template <class SomeLhs, class SomeRhs,
ResultType (*callback)(SomeLhs&, SomeRhs&), bool symmetric = false>
struct Etas
{
typedef Private::FnDispatcherHelper<
BaseLhs, BaseRhs, SomeLhs, SomeRhs, ResultType,
ApplyInnerType2<CastingPolicy, SomeLhs,BaseLhs>::type,
ApplyInnerType2<CastingPolicy,SomeRhs,BaseRhs>::type,
callback> Local;
enum {sym = symmetric};
typedef SomeLhs Lhs;
typedef SomeRhs Rhs;
};
// EtasType has to be a template parameter. If one tries to use
// a parameter of type Etas the MSVC 6.0 won't generate correct
// code.
template <class EtasType>
void Add(EtasType EtasObj)
{
typedef typename EtasType::Local Local;
typedef typename EtasType::Lhs SomeLhs;
typedef typename EtasType::Rhs SomeRhs;
Add(&Local::Trampoline, ::Loki::Type2Type<SomeLhs>(),
::Loki::Type2Type<SomeRhs>());
if (EtasType::sym)
{
Add(&Local::TrampolineR, ::Loki::Type2Type<SomeRhs>(),
::Loki::Type2Type<SomeLhs>());
}
}
// alternative workaround for FnDispatcher::Add
template <class SomeLhs, class SomeRhs,
ResultType (*callback)(SomeLhs&, SomeRhs&), bool symmetric = false>
struct AddI
@ -795,6 +841,8 @@ namespace Private
// Mar 20. 2003: Fixed Bugs in FnDispatcherHelperBase, FnDispatcher::Add and
// FunctorDispatcher::Add.
// New Interface for FnDispatcher::Add.B.K.
// Mar 21, 2003: Added new explicit template argument specification workaround
// for FnDispatcher::Add B.K.
////////////////////////////////////////////////////////////////////////////////
#endif