Description
In the following code:
app:query_tracked "?button[x >= 1] :set {
colour = CYAN;
}...any button whose x value is greater than 0 should have its colour set to cyan.
Restoration is another issue, however. Consider the following cases:
button1:set_colour "random()"
button2:set_colour "$$button1.colour"
If, to restore the value, it uses the computed value, button1 will have the same, correct colour, but button2 will lose its reference to button1, so if button1 changes its colour, button2 won't update like it should.
Otherwise, if to restore the value, it uses the raw dynamic value (e.g. "random()"), non-pure values will be re-evaluated and won't necessarily be the same.
I'd suggest that having references to other sheets is more important, so it would use the raw dynamic value and live with the occasional restoration mistake (it can be warned against and users can avoid using set() on tracked queries and just use themes (#)17 or something).