Hot reloading thoughts

[UkoeHB]

Here are some preliminary thoughts about how to implement hot-reloading.

1. Add extra inner id to widgets.

• Widget paths point to widgets with the highest current inner ids (among widgets with the same name).
• Widgets that don't have the highest current inner id are garbage collected.
  • When rebuilding a UI branch, increment the inner id of the branch root widget and all its descendents.

2. Track which UI branches use specific styles.

• If a style changes in-file, rebuild the UI branches that use that style.

3. Track which function calls generate which UI branches.

• When the file-tracker identifies that a hot-reload-marked function has changed, rebuild the UI branches that were generated by that function (i.e. call that function again).