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/**
** \file misc/endomap.hh
** \brief Declaration of misc::endomap.
*/
#pragma once
#include <list>
#include <map>
#include <misc/map.hh>
namespace misc
{
/** \brief A renaming mapping defaulting to identity:
Mapping a class with itself (endomorphism).
Unless a value is already mapped onto another, map it to itself
if nonstrict. This is a special case of std::map. */
template <class T> class endomap : public map<T, T>
{
public:
/// Super class type.
using super_type = map<T, T>;
// Import overloaded virtual functions.
using super_type::operator[];
using super_type::operator();
enum class strictness_type
{
/// Querying about an unknown identifier returns itself.
nonstrict,
/// Querying about an unknown identifier is an error.
strict
};
/// \name Constructors and destructor.
/// \{
endomap();
/// \}
/// Return a duplicate of \a this.
endomap* clone() const override;
/// Return a reference to the value associated to \a t.
///
/// If \a t was not inserted before, then, contrary to std::map,
/// we insert t -> t into the map, instead of `t -> T()'. This
/// spares the construction of a new T, which may have nasty
/// effects if this constructor has side effects (e.g.,
/// incrementing a counter).
virtual T& operator[](const T& t);
/// Lookup for \a t, returning it if unknown.
T operator()(const T& t) const override;
protected:
/// If strict, queries for an unknown (unmapped) Identifier is an error.
strictness_type strictness_;
};
} // namespace misc
#include <misc/endomap.hxx>
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