Like everything else in the Wolfram System, the textual forms of expressions can themselves be represented as expressions. Textual forms that consist of one‐dimensional sequences of characters can be represented directly as ordinary Wolfram System strings. Textual forms that involve subscripts, superscripts, and other two‐dimensional constructs, however, can be represented by nested collections of two‐dimensional boxes.
|one‐dimensional strings||InputForm,FullForm, etc.|
|two‐dimensional boxes||StandardForm,TraditionalForm, etc.|
If you use the notebook front end for the Wolfram System, then you can see the expression that corresponds to the textual form of each cell by using the Show Expression menu item.
|ToString[expr,form]||create a string representing the specified textual form of expr|
|ToBoxes[expr,form]||create a box structure representing the specified textual form of expr|