generics.c

#include <assert.h>
#include <inttypes.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>

/* Type Compatibility */
#define is_compatibleT(_CX, _CT) _Generic((_CX), _CT:1, default: 0)
#define is_compatibleV(_C2X, _C2V) is_compatibleT (_C2X, typeof (_C2V))
#define ensure_type(_EP, _ET) _Static_assert(is_compatible(_EP, _ET), \
    "incorrect type for parameter '" #_EP "', expected " #_ET)

/* Generic Prints */
#define printf_dec_format(x) _Generic ((x), \
  char: "%c", \
  signed char: "%hhd", \
  unsigned char: "%hhu", \
  signed short: "%hd", \
  unsigned short: "%hu", \
  signed int: "%d", \
  unsigned int: "%u", \
  long int: "%ld", \
  unsigned long int: "%lu", \
  long long int: "%lld", \
  unsigned long long int: "%llu", \
  float: "%f", \
  double: "%f", \
  long double: "%Lf", \
  char *: "%s", \
  void *: "%p")

#define print(x) printf (printf_dec_format (x), x)
#define printnl(x) printf (printf_dec_format (x), x), printf ("\n");


/* Get the name of a type */
#define typename(x) _Generic ((x), _Bool: "_Bool", \
  char: "char", \
  signed char: "signed char", \
  unsigned char: "unsigned char", \
  const char: "const char", \
  short int: "short int", \
  unsigned short int: "unsigned short int", \
  int: "int", \
  unsigned int: "unsigned int", \
  long int: "long int", \
  unsigned long int: "unsigned long int", \
  long long int: "long long int", \
  unsigned long long int: "unsigned long long int", \
  float: "float", \
  double: "double", \
  long double: "long double", \
  char *: "pointer to char", \
  void *: "pointer to void", \
  int *: "pointer to int", \
  default: "other")

  void
test_typename (void)
{
  size_t s;
  ptrdiff_t p;
  intmax_t i;

  int ai[3] = {0};

  const short sh = 10;

  printf ("size_t is '%s'\n", typename (s));
  printf ("ptrdiff_t is '%s'\n", typename (p));
  printf ("intmax_t is '%s'\n", typename (i));

  printf ("character constant is '%s'\n", typename ('0'));
  printf ("0x7FFFFFFF is '%s'\n", typename (0x7FFFFFFF));
  printf ("0xFFFFFFFF is '%s'\n", typename (0xFFFFFFFF));
  printf ("0x7FFFFFFFU is '%s'\n", typename (0x7FFFFFFFU));
  printf ("array of int is '%s'\n", typename (ai));

  printf ("short constant is '%s'\n", typename (sh));
}

  void
test_equality (void)
{
  enum e { E1 };
  bool ei = is_compatibleT (E1, int);
  printf ("%s e :==: int\n", ei ? "True":"False");
}

  int
main (int argc, char *argv[], char **env)
{
  test_typename ();
  test_equality ();
  return 0;
}