cube casts a cube into a cube. Used to resolve ambiguity resulting from two or more function signatures with the same name. For example, assume that you have two function signatures. One takes a cube and the other takes a measure. If the name of the cube and the measure are the same, then invoking that function in a formula creates ambiguity. By explicitly casting the string with the cube function, the ambiguity is resolved.
cube(cubeObj)