ToME: the Tales of Maj'Eyal

Code: Select all

/*
 * this function activates one trap type, and returns
 * a bool_ indicating if this trap is now identified
 */
bool_ player_activate_trap_type(s16b y, s16b x, object_type *i_ptr, s16b item)
{
	bool_ ident = FALSE;
	s16b trap;

	s16b k, l;

	trap = cave[y][x].t_idx;

	if (i_ptr != NULL)
	{
		trap = i_ptr->pval;
	}

	switch (trap)
	{
		/* stat traps */
	case TRAP_OF_WEAKNESS_I:
		ident = do_dec_stat(A_STR, STAT_DEC_TEMPORARY);
		break;
	case TRAP_OF_WEAKNESS_II:
		ident = do_dec_stat(A_STR, STAT_DEC_NORMAL);
		break;
	case TRAP_OF_WEAKNESS_III:
		ident = do_dec_stat(A_STR, STAT_DEC_PERMANENT);
		break;
	case TRAP_OF_INTELLIGENCE_I:
		ident = do_dec_stat(A_INT, STAT_DEC_TEMPORARY);
		break;
/*** Continues this way for a long while ***/

Code: Select all

    switch (condition_var) {
         case FOO: foo(&ident); break;
         case BAR: bar(&ident); break;
         ...
    }

Code: Select all

    switch (condition_var) {
       case FOO: tie(ident, cost) = foo(); break;
    }

Code: Select all

    map<int, std::function(...)> callbacks;
    callbacks[condition_var](...);

Code: Select all

/* Somewhere in the headers */
#define gen_potion_func(x, y) ((x))(int pval, int pval2) { return ((y))(pval, pval2); }
gen_potion_func(SV_POTION_FOO_BAR, effect_bless);
gen_potion_func(SV_POTION_FOO_BUZ, effect_bless);
gen_potion_func(SV_POTION_BUZ_BUZ, effect_confuse);
/* etc. */
...

/* Somewhere inside the potion quaffing function */
#define call_potion_func(x) (x)(pval, pval2)
call_potion_func(sval);

Code: Select all

using std::bind;

// A trap handler takes y, x parameters and return an ident flag
typedef std::function<bool(int, int)> TrapCallback;

// A map to look up a trap type and return a handler for that type
const std::map<int, TrapCallback> traps {
  // Create function objects that call do_dec_stat with the appropriate parameters.
  // It's okay that it doesn't need the x, y parameters we're passing in.
  { TRAP_OF_WEAKNESS_I, bind(do_dec_stat, A_STR, STAT_DEC_TEMPORARY) },
  { TRAP_OF_WEAKNESS_II, bind(do_dec_stat, A_STR, STAT_DEC_NORMAL) },
  { TRAP_OF_WEAKNESS_III, bind(do_dec_stat, A_STR, STAT_DEC_PERMANENT) },

  // For more complicated traps, you can use lambdas
  { TRAP_OF_EARTHQUAKE, [](int y, int x) {
    msg_print("As you touch the trap, the ground starts to shake.");
    earthquake(y, x, 10);
    return true;
  }}
};

bool player_activate_trap_type(int y, int x, int trap)
{
  // Gets an iterator pointing to the requested trap
  auto handler = traps.find(trap);
  if (handler == trap.end()) {
    // Error: unknown trap
  } else {
    // Invoke the handler
    handler->second(y, x);
  }
}

Code: Select all

class Trap {
public:
  virtual void PlayerActivate(int y, int x) = 0;
};