# Room events

 Event Handler arguments and meaning --- --- start function() once when the copy starts, before players enter enter function(player) when someone joins leave fu

| Event | Handler arguments and meaning |
| --- | --- |
| `start` | `function()` once when the copy starts, before players enter |
| `enter` | `function(player)` when someone joins |
| `leave` | `function(player)` when someone leaves |
| `click` | `function(player, thing)` after the player reaches the clicked thing |
| `walk_on` | `function(player, thing)` when stepping onto a visible thing |
| `walk_off` | `function(player, thing)` when stepping off |
| `timer` | `function(tag)` for an `after` or `every` timer |
| `key` | `function(player, key)` for game keys such as `space`, `w`, `up`, `1` |
| `ui` | `function(player, id, value)` for a button, submitted input or selected friend |
| `window_closed` | `function(player, id)` when the player clicks the native window X |
| `send_failed` | `function(player, room, why)` when a scripted room transfer fails |

`player` contains `id` and `name`. `thing` contains `id`, `name`, `x`, `y`,
`hidden`, and `item` (the id of the item it is an instance of). Most object/player arguments accept a table or its id string; use the
player table for overloaded UI verbs such as `banner(player, text)`.
`players()` additionally provides player `x` and `y`. `player(idOrPlayer)`
returns the current row for just one player in this copy, or nil if absent. Use
that when updating a bounded group in a large room, to avoid constructing a Lua
table for everyone on each tick.
Coordinates are tiles local to the room, starting at `(0, 0)`.