41. The method of claim 39, further including: when the navigation of the right operand is specified by a user inputting a second indicator, setting the current selection to a crown selection so that when the user then inputs another computational construct the computational construct will be replaced by the other computational construct.
41. The method of claim 39, further including: when the navigation of the right operand is specified by a user inputting a second indicator, setting the current selection to a crown selection so that when the user then inputs another computational construct the computational construct will be replaced by the other computational construct. 42. The method of claim 41 wherein the first indicator is a tab and the second indicator is a shift-tab.