Allow custom math variables to be used as var for UI widgets

[Standing-Storm]

Is your feature request related to a problem? Please describe.

Just calculated out how much JSON it would take it make a lilin ruach counter that works like the mana gauge and the answer is something like 10,000 lines. It'd be nice if the var parameter could take custom u_variables, which would open up vitamins and other counters to be used to more easily make UI widgets.

Solution you would like.

A way to use custom u_vars in UI widgets.

Describe alternatives you have considered.

10,000 lines

(I'm not seriously considering it)

Additional context

No response

[andrei8l]

Is #71070 not sufficient?

[Standing-Storm]

Is #71070 not sufficient?

Is it possible to use this to create graphs that fill? I could use this for a numerical version (thank you for letting me know it existed!), but it doesn't seem like it would work for a fillable graph, bar having some massive EoC running behind the scenes that set a string var to display in the widget.