Show warning when math equation is invalid

[ShahriarKh]

What's your feature?

Currently, if the user enters an invalid math equation, there's no way to let them know there was an error, and the chart also displays incompletely.

Maybe we can do something like what Obsidian Dataview does: showing a warning message instead of showing an incomplete element.

Any related problems?

No response

Additional context?

No response

[leonhma]

Another great idea! The intention is to just silently update the plot but if the user finished typing and the expression is still invalid, we should display a warning, I agree.