succ()
Returns the Integer equal to int + 1.
1.next #=> 2 (-1).next #=> 0
static VALUE int_succ(VALUE num) { if (FIXNUM_P(num)) { long i = FIX2LONG(num) + 1; return LONG2NUM(i); } return rb_funcall(num, '+', 1, INT2FIX(1)); }