We support directly nested layouts, but we did not support indirect
nesting:
GridLayout {
Rectangle {
l2 := GridLayout { ... }
}
}
This patch fixes that by detecting this scenario and merging the layout
info of the element (Rectangle) and the layout inside (l2). This makes
it much easier to create re-usable components that use layouts
themselves and allows placing them in layouts.
This does not actually merge so much but it is better than nothing.
I was not able to merge the code from the interpreter because of the life time issues
It doesn't really make sense to have them in the API, the grid layout is
supposed to "own" the surrounding space. That can be an element and then
it should be a (0, 0) and distribute the element's width/height, or in
the future it can be a cell of a grid layout. Then there's an (x/y), but
that's implicit / hidden.
Instead of storing the "within" element that we unconditionally take the
"width" and "height" properties from, let's pass through a property
reference expression to the width/height to use. For now that's still
the layout parent's width/height, but with this it can be replaced in
the future to refer to a "virtual" property that belongs to parent cell.
