make_enum.hpp File Reference

Defines the MAKE_ENUM macro. More...

#include <cassert>
#include <exception>
#include <string>
#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/seq/for_each.hpp>
#include <boost/preprocessor.hpp>
#include <istream>
#include <ostream>

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Classes
class	bad_enum_cast
class	enum_tag

Namespaces
	make_enum_detail

Macros
#define	ADD_PAREN_1(A, B)   ((A, B)) ADD_PAREN_2
#define	ADD_PAREN_2(A, B)   ((A, B)) ADD_PAREN_1
#define	ADD_PAREN_1_END
#define	ADD_PAREN_2_END
#define	MAKEPAIRS(INPUT)   BOOST_PP_CAT(ADD_PAREN_1 INPUT,_END)
#define	PP_SEQ_FOR_EACH_I_PAIR(macro, data, pairs)   BOOST_PP_SEQ_FOR_EACH_I(macro, data, MAKEPAIRS(pairs))
#define	CAT2(A, B)   A ## B
#define	CAT3(A, B, C)   A ## B ## C
#define	EXPAND_ENUMVALUE_NORMAL(r, data, i, record)   BOOST_PP_TUPLE_ELEM(2, 0, record) = i,
#define	EXPAND_ENUMFUNC_NORMAL(r, data, i, record)   if(data == BOOST_PP_TUPLE_ELEM(2, 1, record)) return BOOST_PP_TUPLE_ELEM(2, 0, record);
#define	EXPAND_ENUMPARSE_NORMAL(r, data, i, record)   if(data == BOOST_PP_TUPLE_ELEM(2, 1, record)) { *this = BOOST_PP_TUPLE_ELEM(2, 0, record); return true; }
#define	EXPAND_ENUMFUNCREV_NORMAL(r, data, i, record)   if(data == BOOST_PP_TUPLE_ELEM(2, 0, record)) return BOOST_PP_TUPLE_ELEM(2, 1, record);
#define	EXPAND_ENUMFUNCTIONCOUNT(r, data, i, record)   + 1
#define	MAKE_ENUM(NAME, CONTENT)

Functions
void	make_enum_detail::debug_conversion_error (const std::string &temp, const bad_enum_cast &e)

Detailed Description

Defines the MAKE_ENUM macro.

Currently this comes in 1-argument and 2-argument versions.

Example usage:

#include "utils/make_enum.hpp"

MAKE_ENUM(enumname,
    (val1, "name1")
    (val2, "name2")
    (val3, "name3")
)

What it does:

Generates a struct enumname which holds an enum and provides functions to convert to and from string, as well as a constant enumname::count, which is set to the number of possible enum values defined.

// Throws bad_enum_cast if the string value is not recognized.
enumname enumname::string_to_enum(const std::string&);

// Returns the specified default instead of throwing if the string value is
// not recognized. Never throws.
enumname enumname::string_to_enum(const std::string&, enumname);

// Never throws.
std::string enumname::enum_to_string(enumname);

// Count of defined enum values.
const size_t enumname::count;

It also defines the following stream operations:

// Never throws. Fails an assertion check if the value passed is not defined
// by the enumeration.
std::ostream& operator<<(std::ostream&, enumname);

// Never throws. Sets the stream's fail bit if the input is not recognized.
std::istream& operator>>(std::istream&, enumname&);

In case of a bad string -> enum conversion from istream input, the istream will have its fail bit set. This means that lexical_casts will throw a bad_lexical_cast in the similar scenario; however, note that bad_lexical_cast does not provide any details about the error.

It is recommended to use MAKE_ENUM types with the built-in versions of lexical_cast or lexical_cast_default provided by Wesnoth (see util.hpp). However, if you do not want twml_exception to be thrown under any circumstances, use the string_to_enumname functions instead.

See src/tests/test_make_enum.cpp for example code.

Definition in file make_enum.hpp.

Macro Definition Documentation

#define ADD_PAREN_1	(		A,
			B
	)		((A, B)) ADD_PAREN_2

Definition at line 128 of file make_enum.hpp.

#define ADD_PAREN_1_END

Definition at line 130 of file make_enum.hpp.

#define ADD_PAREN_2	(		A,
			B
	)		((A, B)) ADD_PAREN_1

Definition at line 129 of file make_enum.hpp.

#define ADD_PAREN_2_END

Definition at line 131 of file make_enum.hpp.

#define CAT2	(		A,
			B
	)		A ## B

Definition at line 136 of file make_enum.hpp.

#define CAT3	(		A,
			B,
			C
	)		A ## B ## C

Definition at line 137 of file make_enum.hpp.

#define EXPAND_ENUMFUNC_NORMAL	(		r,
			data,
			i,
			record
	)		if(data == BOOST_PP_TUPLE_ELEM(2, 1, record)) return BOOST_PP_TUPLE_ELEM(2, 0, record);

Definition at line 144 of file make_enum.hpp.

#define EXPAND_ENUMFUNCREV_NORMAL	(		r,
			data,
			i,
			record
	)		if(data == BOOST_PP_TUPLE_ELEM(2, 0, record)) return BOOST_PP_TUPLE_ELEM(2, 1, record);

Definition at line 148 of file make_enum.hpp.

#define EXPAND_ENUMFUNCTIONCOUNT	(		r,
			data,
			i,
			record
	)		+ 1

Definition at line 151 of file make_enum.hpp.

#define EXPAND_ENUMPARSE_NORMAL	(		r,
			data,
			i,
			record
	)		if(data == BOOST_PP_TUPLE_ELEM(2, 1, record)) { *this = BOOST_PP_TUPLE_ELEM(2, 0, record); return true; }

Definition at line 146 of file make_enum.hpp.

#define EXPAND_ENUMVALUE_NORMAL	(		r,
			data,
			i,
			record
	)		BOOST_PP_TUPLE_ELEM(2, 0, record) = i,

Definition at line 140 of file make_enum.hpp.

#define MAKE_ENUM	(		NAME,
			CONTENT
	)

Definition at line 157 of file make_enum.hpp.

#define MAKEPAIRS

(

INPUT

)

BOOST_PP_CAT(ADD_PAREN_1 INPUT,_END)

Definition at line 132 of file make_enum.hpp.

#define PP_SEQ_FOR_EACH_I_PAIR	(		macro,
			data,
			pairs
	)		BOOST_PP_SEQ_FOR_EACH_I(macro, data, MAKEPAIRS(pairs))

Definition at line 133 of file make_enum.hpp.