Why loop about event need twice

[kissdata]

When it comes to Event, most of code in examples look like this:

for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
    switch t := event.(type) {
    ...
    } 
}

Why the event (a interface) should be written = sdl.PollEvent() twice?

[veeableful]

Hi @kissdata, it is a standard for-loop in Go. You can see an explanation of it here.

We use it in the examples to extract all the Events in current frame until there's no more.

[kissdata]

I known it, for-loop with 3 expressions, so does in c/cpp. I now reading the article recommended by wiki.libsdl.org (ranked 6th) , he used a while-loop to process event:

while (SDL_PollEvent(&e)) {
    if (e.type == SDL_QUIT) {
        // ...
    }
    if (e.type == SDL_KEYDOWN) {
        // ...
    }
}

oh 👀 so short, if I use go recode it, this for-loop looks longer than original statement. I want see if exists a better way to implement it.