ComputedDoc example
CaminoReal's expression language supports an assignment statement. Also, expressions assigned to variables are maintained in a symbol table. If desired, the math expressions imbedded in a Tioga document can be evaluated prior to being painted, whenever the document is displayed, and so can be defined as functions of other expressions. This makes possible Tioga documents that are "spreadsheets" or "mathematical form letters", or simply "computed documents". Having the math in a technical paper computed on the fly minimizes the introduction of typographical errors, and so reduces the burden of proofreading.
Let's look at an example of this. Here's a document with evaluationbeforepaint turned off. The polynomials F and G are input data, and from them a matrix and determinant are derived. When we turn evaluationbeforepaint on and repaint, this is the result. Now let's change F, set the new value back into the document, and "recompute the document".
Change is delete -3xy term of F.