interface composability is an issue

[tonyhffong]

Right now, every widget created is quite monolithic, you cannot easily put them together to create a more complex widget. We need to change that.

Concepts needed:

• a general visual container type (not just the screen). I think vertical list and horizontal list would be a start. They could be nested.
• abstract away standard ncurses functions: mvwprintw, mvwaddch, box, werase, wattron, wattroff. The goal is to handle nested geometries -- widgets do not need to worry about its place in the larger canvas.
• formalize navigation rule to ensure consistent experience no matter how a widget is structured.
  • tab/shift-tab navigation rule
  • arrow keys navigation rule (how to enable it? special Function key to switch mode?)
  • canvas-shifting rule

The branch tf/composability would be where I'd experiment on such concepts.

[tonyhffong]

next batch of required concepts:

• inter-widget communication. We need these widgets to interact with a state in an easy (and hopefully safe) way. factors to consider:
  • widget to state variable
  • state variable to widget
  • container variables with static length
  • container variables with both the size and content dependent on state
  • partial input rules ("1e" in a floating point input, or temporarily inconsistent input among widgets)
  • partial output rules (we know a widget is invalid, but we haven't computed the right value yet)