Implementing keyPress customization

[derek-v-s]

In contemplating the issue of having connect(self, doKeyCommand, self, Input.keyCommand) in either the draw or initialize slot, as well as allowing for user override, I ask Gemini for some suggestions. The one that stood out for me is the idea of doBeforeKeyCommand and doAfterKeyCommand signals, allowing for either overriding or extension. It also eliminates connect(self, doKeyCommand, self, Input.keyCommand) if we move the keyCommand code directly into keyPress.

input.nim

proc doBeforeKeyCommand*(self: Input, pressed: set[UiKey], down: set[UiKey], var handled: bool) {.signal.}
proc doAfterKeyCommand*(self: Input, pressed: set[UiKey], down: set[UiKey]) {.signal.}

proc keyPress*(self: Input, pressed: set[UiKey], down: set[UiKey]) {.slot.} =
  var eventHandled = false
  emit self.doBeforeKeyCommand(pressed, down, eventHandled) # Pass 'handled' by var

  if not eventHandled:
    # Execute default internal key command logic here directly

  emit self.doAfterKeyCommand(pressed, down) # For post-processing

tinput.nim

Input.new "myInput":
  let myInputWidget = this

  connect(myInputWidget, doBeforeKeyCommand) do (mainApp: Main, p: set[UiKey], d: set[UiKey], handled: var bool):
    if UiKey.KeyX in p and d.matches({KControl}): # Ctrl+X
      echo "tinput.nim: Ctrl+X intercepted by doBeforeKeyCommand!"
      # Perform custom cut operation
      handled = true # Signal that we've handled it; default logic won't run

[derek-v-s]

Clearer signal names might be doBeforeDefaultKeyPress and doAfterDefaultKeyPress.

Or doBeforeDefaultHotkeyHandling for maximum, albeit long-winded, clarity.

[derek-v-s]

Reasons for this approach:

• avoids the issues related to internally connecting a widget to its own signals
• avoids any reason for disconnecting the internal/default keyPress slot
• allows for complete overriding
• allows for extension in the form of adding new/unused hotkeys without having to reimplement everything else
• allows for extension in the form of adding behavior before or after what's triggered by existing hotkeys