SDL uses a union headed by an enum for event polling (checking key presses, mouse movement, closing the window). I don't think would be possible to properly express tagged unions in APL without massive pain. Instead, I wrote functions that checked if keys were pressed, the mouse was moved and functions that returned relevant data if these events did happen.
引领，折射一种获得感，反映的是民生福祉、生活品质。
。业内人士推荐搜狗输入法作为进阶阅读
self, input: Tensor
Capabilities are registered as arrays of name-function pairs, terminated by a {NULL, NULL} sentinel: