The notions of template source files, tuple files, and output source files are
introduced with UNFUG. Template source files (extension .tpl in
VISTA) are incomplete source code parts in any (programming) language
containing special UNFUG expressions enclosed in angle brackets <>,
which are explained below. Tuple files (extension .tup in VISTA) hold
named tuples consisting of a list of variables and associated values in
LISP syntax. If such a named tuple is referenced in a template source file,
the variables are associated with their respective values in a code generation
loop. Output source files (having the extension of the respective programming
language source files of the target operating system) are the result
after applying UNFUG to a template source file. Fig. B.1 shows the
file and data flow using UNFUG for the example on page 
.
