Support structured local and global variables #1181
Description
We have a request to support structured local and global variables. See https://forum.duet3d.com/topic/38737/creating-tree-hierarchy-in-global-local-variables. For example:
var settings.speed=12000
var settings.accel=6000
M98 P"set_parameters" S{var.settings}
We could allow '.' in variable names to give the appearance of structured variables, but this wouldn't allow us to pass a whole structured variable as a parameter, or assign it to another variable.