Actions

When it comes to extending the behaviour of you window manager, the first and most obvious thing to look at is running some custom code in response to a key binding being pressed. In penrose, this is refered to as an action.

Actions can be anything from focusing a new window, to changing the layout algorithm being used, to opening a terminal or running fully custom logic to find and display amusing pictures of squirrels.

The choice is yours.

To help with some of the boilerplate and common cases, there are a couple of helper functions that will generate a KeyEventHandler for you in a relatively simple way. There are also a couple of built in actions for working with floating windows and exiting penrose to get you started.

Writing actions using helpers

There are five helper functions for writing common actions:

• key_handler: this one is the most general. It wraps a function that takes a mutable reference to the current window manager state and a reference to the XConn used by your window manager and runs whatever custom code you care to write.
• modify_with: for calling pure state methods this helper handles the diff and refresh cycle for you. Simply update the StackSet with whatever changes you want to make and a refresh will be triggered for you to reflect you changes to the X server.
• send_layout_message: this does pretty much what you'd expect. It calls the given function to construct a Message and sends it to the active layout. (Useful for updating your layout behaviour on the fly).
• broadcast_layout_message: does the same thing as send_layout_message only in this case the message is copied and sent to all layouts available to the current workspace rather than just the active one.
• spawn: as the name implies, this spawns a given program as a subprocess. You probably want at least one key binding for spawning either a terminal or a program launcher such as dmenu or rofi. For the programs you use the most, this lets you get to them with a single key press!