> For the complete documentation index, see [llms.txt](https://guide.cronuszen.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guide.cronuszen.com/gpcscripting/gpc-script-guide/advanced-architecture/event-driven-input-routing.md).

# Event-driven input routing

Read only the controls owned by the active state. A small event router is easier to audit than several unrelated blocks that can all mutate the same menu state:

{% code title="event-driven-router.gpc" %}

```cpp
main {
    if(event_press(PS5_UP))         handle_up();
    else if(event_press(PS5_DOWN))  handle_down();
    else if(event_press(PS5_LEFT))  handle_left();
    else if(event_press(PS5_RIGHT)) handle_right();
}

function handle_up()    { set_val(TRACE_1, 1); }
function handle_down()  { set_val(TRACE_1, 2); }
function handle_left()  { set_val(TRACE_1, 3); }
function handle_right() { set_val(TRACE_1, 4); }
```

{% endcode %}

Use separate `if` statements instead when simultaneous directions intentionally need separate actions. Analog magnitude still requires an ordinary input read such as `get_ival`.


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