celeritas::StringEnumMapper< T > Class Template Reference

Map strings to enums for user input. More...

#include <StringEnumMapper.hh>

Public Types
Type aliases
using	EnumCStringFuncPtr = char const *(T)

Public Member Functions
template<class U >
	StringEnumMapper (U &&enum_to_string, char const *desc=nullptr)
	Construct with a "stringify" function. More...
T	operator() (std::string_view s) const
	Convert a string_view to the corresponding enum.

Static Public Member Functions
static StringEnumMapper< T >	from_cstring_func (EnumCStringFuncPtr, char const *desc=nullptr)
	Construct using a to_cstring function.

Detailed Description

template<class T>
class celeritas::StringEnumMapper< T >

Map strings to enums for user input.

Note that since a map is built at construction time, instances of this class should be static to amortize the cost. The strings being converted must exceed the lifetime of this class. (Usually it references const char*.)

Todo:

If the size of the strings is short and there aren't a lot of them, it will be faster to use a fixed-size array and search over them.

Example:

void from_json(const nlohmann::json& j, GeantSetupOptions& opts)
{
    static auto gspl_from_string
        = StringEnumMapper<PhysicsList>::from_cstring_func(
            to_cstring, "physics list");
    opts.physics = gspl_from_string(j.at("physics").get<std::string>());
}

Constructor & Destructor Documentation

StringEnumMapper()

template<class T >

template<class U >

celeritas::StringEnumMapper< T >::StringEnumMapper ( U &&  enum_to_string, char const *  desc = nullptr  )

inlineexplicit

Construct with a "stringify" function.

The result just has to be implicitly convertible to a std::string_view .

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The documentation for this class was generated from the following file:

• StringEnumMapper.hh