Authors have the ability to place the command
syscall{text}{action} at any point in the TEX document.
This command takes two arguments; the first one text is the text that
appears in the document with a box around it. Thus the command
syscall{text}{action} will appear as .
Hitting the middle mouse button within such a box, will issue a system
call with the unix command action. This TEX system call is how the
author and reader interact.
For convenience there are plot commands for figures, which automatically
connect the figure filename with an action stored in a cakefile. This cakefile
is in the same directory as the TEX document. Thus typing activeplot{name}{height}{caption} will create an active figure.
This command includes a PostScript file, given in file name.ps, specifies the height of the figure and puts some caption on the bottom. The figure caption will include a button labeled: name. When the button is pressed the system call: cake name will be executed.