shiva::pp

shiva::pp provides basic preprocessing utilities.

The pp_stringify macro allows converting its parameter to a string litteral.

pp_stringify(param)

const char *str = pp_stringify(hello);
//str is now "hello"

The pp_stringviewify macro allows converting its parameter to a constexpr std::string_view.

pp_stringviewify(param)

constexpr std::string_view sv = pp_stringviewify(hello);
//sv is now {"hello", 5}

The pp_paste macro allows concatenating its parameters together to form a new token.

pp_paste(param1, param2)

int var1 = 1;
pp_paste(var, 1) = 2;
//var1 is now 2

The pp_first_arg macro allows extracting the first parameter from a variadic macro parameter list (usually represented as __VA_ARGS__).

pp_first_arg(...)

int first = pp_first_arg(1, 2, 3);
//first is now 1

The pp_count_args macro allows counting the number of parameters passed to a variadic macro.

pp_count_args(...)

int nb = pp_count_args(1, 2, 3, 4, 5);
//nb is now 5

The pp_for_each macro allows applying a given macro to each argument of a variadic macro parameter list.

pp_for_each(apply, ...)

#define doubleParam(a)      (a * 2),

std::vector<int> v{pp_for_each(doubleParam, 1, 2, 3)};
//v is now {2, 4, 6}

#define incrementIBy(nb)    i += nb;

int i = 0;
pp_for_each(incrementIBy, 1, 2, 3);
//i is now 6

Last updated 7 years ago