34. The method of claim 33, further including: when the navigation of the left operand is completed by the user inputting a second indicator, setting a current selection to a selection of the representation of the computational construct and its operands in a tree selection mode so that when the user then inputs a binary operator the computational construct will be replaced by the binary operator.
34. The method of claim 33, further including: when the navigation of the left operand is completed by the user inputting a second indicator, setting a current selection to a selection of the representation of the computational construct and its operands in a tree selection mode so that when the user then inputs a binary operator the computational construct will be replaced by the binary operator. 35. The method of claim 34 wherein the first indicator is a tab and the second indicator is a shift-tab.