Assign variables request

[apb-reports]

When using vega lite with javascript (web apps etc) I can easily pull a value into a variable/cont and place this in the vega lite spec and the spec uses the value. For example if I wanted to dynamically assign the Height step I could do this:

const V5Data = myDataSource;
const rowCount = V5Data.length;
const stepSize = rowCount < 4 ? 30 : 20;

var V5Spec = {
"$schema": "https://vega.github.io/schema/vega-lite/v5.json",
"data": {"values": V5Data},
"width": "container",
"height": {"step": stepSize}....

I was hoping you could consider adding some code so we could do this in Deneb.
For example if we wrapped a value like [[xxxx]] in double brackets you could obtain the actual value and not the name of the field/measure. This would make for some very dynamic charts and remove much of the complexity often used with transforms etc.

Just an idea for future development.

Keep up the amazing work Daniel!