Appliance development toolkit with editor to create shared variable namespace

An appliance development toolkit according to the invention is provided to enable creation of content to affect operation of a component in an appliance or to affect user interaction with an appliance. The toolkit comprises an editor configured to enable creation of a variable holder, to associate the variable holder with a variable, to create a value holder related to a valid value of the variable, and to associate the variable holder with the value holder. A user can use either of the variable holder or the value holder in creating a hierarchy of elements for content independent of any relationship that may otherwise exist between the variable and other elements and between the value and other elements. With this structure, the variable and the value can be used in different contexts with different relationships while maintaining their relationship with each other by way of the variable holder and the value holder.