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Merge branch 'feature/c++11_visitor' into development

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John Wellbelove 2019-03-30 10:00:22 +00:00
commit 9375c07e63
1 changed files with 67 additions and 5 deletions
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72
include/etl/visitor.h
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@ -40,16 +40,45 @@ SOFTWARE.
/// structure on which it operates. A practical result of this separation is the
/// ability to add new operations to existing object structures without modifying
/// those structures. It is one way to easily follow the open/closed principle.
/// In essence, the visitor allows one to add new virtual functions to a family
/// of classes without modifying the classes themselves; instead, one creates a
/// In essence, the visitor allows one to add new virtual functions to a family
/// of classes without modifying the classes themselves; instead, one creates a
/// visitor class that implements all of the appropriate specialisations of the
/// virtual function. The visitor takes the instance as input, and implements
/// virtual function. The visitor takes the instance as input, and implements
/// the goal through double dispatch.<br>
/// \ingroup patterns
//*****************************************************************************
namespace etl
{
#if ETL_CPP11_SUPPORTED && !defined(ETL_VISITOR_FORCE_CPP03)
//*****************************************************************
/// The visitable class for N types.
///\ingroup visitor
//*****************************************************************
template <typename T1, typename... Types>
class visitable : public visitable<T1>, public visitable<Types...>
{
public:
using visitable<T1>::accept;
using visitable<Types...>::accept;
};
//*****************************************************************
/// The specialised visitable class for 1 type.
///\ingroup visitor
//*****************************************************************
template <typename T1>
class visitable<T1>
{
public:
virtual void accept(T1&) = 0;
};
#else
//*****************************************************************
/// The visitable base class for four visitor types.
/// Derive visitable classes from this.
@ -108,6 +137,37 @@ namespace etl
virtual void accept(T1&) = 0;
};
#endif
#if ETL_CPP11_SUPPORTED && !defined(ETL_VISITOR_FORCE_CPP03)
//*****************************************************************
/// The visitor class for N types.
///\ingroup visitor
//*****************************************************************
template <typename T1, typename... Types>
class visitor : public visitor<T1>, public visitor<Types...>
{
public:
using visitor<T1>::visit;
using visitor<Types...>::visit;
};
//*****************************************************************
/// The specialised visitor class for 1 type.
///\ingroup visitor
//*****************************************************************
template <typename T1>
class visitor<T1>
{
public:
virtual void visit(T1&) = 0;
};
#else
//*****************************************************************
/// The visitor base class for sixteen types.
/// Derive visitors from this.
@ -115,7 +175,7 @@ namespace etl
//*****************************************************************
template <typename T1, typename T2 = void, typename T3 = void, typename T4 = void,
typename T5 = void, typename T6 = void, typename T7 = void, typename T8 = void,
typename T9 = void, typename T10 = void, typename T11 = void, typename T12 = void,
typename T9 = void, typename T10 = void, typename T11 = void, typename T12 = void,
typename T13 = void, typename T14 = void, typename T15 = void, typename T16 = void>
class visitor
{
@ -323,7 +383,7 @@ namespace etl
virtual void visit(T8&) = 0;
virtual void visit(T9&) = 0;
};
//*****************************************************************
/// The visitor base class for eight types.
/// Derive visitors from this.
@ -459,6 +519,8 @@ namespace etl
virtual void visit(T1&) = 0;
};
#endif
}
#endif