Multi-purpose key

Multi-purpose key with alone_timeout_millis

To make capslock also work as esc, if it's pressed and released within a timeout:

modmap:
  - remap:
      Capslock:
        held: Capslock
        alone: esc
        alone_timeout_millis: 200 # Optional, defaults to 1000

It works like this:

• If the key is pressed and released within alone_timeout_millis without other keys being pressed, it's considered alone.
• If another key is pressed before timeout, it's considered held.
• If the timeout is reached without other things happening, it's considered held.

The alone-action is emitted as press and release right away. The held-action will emit press when it's triggered and wait to release until the trigger key is released.

Multi-purpose key with free hold

To use space as shift when it's held down, but remain space if it's not interrupted by another key:

modmap:
  - remap:
      Space:
        held: Shift_L
        alone: Space
        free_hold: true # Optional, defaults to false.

There's no timeout in this case (i.e. alone_timeout_millis is ignored).

• The held action is triggered when another key is pressed while the multi-purpose key is being held down.
• If the key is released without others key being pressed, it triggers the alone action.

This allows a key to be held indefinitely without triggering its held state, which is ideal for keys that also serve as modifiers. In this case, you make the Space key act as Shift when held and another key is pressed, but still type a regular Space when tapped.

A drawback of this configuration is, that space can't be used for repeating spaces when held down, because that now has new meaning.

Another drawback is that fast writing (e.g. a, space, l) can emit aL. One has to release space before typing l to get a l. This can be fixed with hold_threshold_millis.

free_hold is logically the same as having an infinite alone_timeout_millis.

Multi-purpose key with hold_threshold_millis

modmap:
  - remap:
      Space:
        held: Shift_L
        alone: Space
        hold_threshold_millis: 200
        free_hold: true

This will emit the alone-action, space, when it's interrupted by another key before timeout of hold_threshold_millis. This allows space to function normally when typing fast. And only after the timeout will it work as shift.

Multi-purpose key with interruptable

You may not want tapping a multi-purpose key to always be interrupted by all types of input events. You may also have problems tapping multi-purpose keys if you're pressing a lot of keys at once.

You can control which keys can interrupt the alone press of a multi-purpose key using the interruptable field:

modmap:
  - remap:
      Ctrl_L:
        held: Ctrl_L
        alone: Backspace
        interruptable:
          # Ignore mouse movement when using --mouse
          # This is the default
          not: [XRIGHTCURSOR, XLEFTCURSOR, XDOWNCURSOR, XUPCURSOR]
      Alt_L:
        held: Alt_L
        alone: Space
        alone_timeout_millis: 200
        interruptable:
          # Only allow alt+tab to interrupt tapping alt
          only: Tab

Input events that would interrupt the alone press of these multi-purpose keys will be handled as normal but without interrupting the key press.

You can set interruptable: false to completely disable interruption. Or let all keys interrupt by setting interruptable: true, which also lets mouse wheel and mouse movement interrupt.