Coro::State			T_PTROBJ
Coro::State_or_hashref		T_STATE_OR_HASHREF

INPUT

T_STATE_OR_HASHREF
	{
           SV *arg = $arg;
           if (SvROK (arg) && SvTYPE(SvRV(arg)) == SVt_PVHV)
             {
               SV **state = hv_fetch((HV *)SvRV(arg), \"_coro_state\", 11, 0);
               if (!state)
                 croak (\"${Package}::$func_name() -- $var is a hashref but lacks the _coro_state key\");
               arg = *state;
             }
              
           /* must also be changed inside Coro::Cont::result */
           if (sv_derived_from (arg, \"Coro::State\"))
             $var = ($type) SvIV((SV*)SvRV(arg));
           else
             croak (\"${Package}::$func_name() -- $var is not (and contains not) a Coro::State object\");
        }