a new statement [filter]
syntax:
[filter funcion_name]....[end]
everything which is between [filter] and [end] is processed normally and
at the end it is passed to the function (function_name)
FunInfo struct has 'in' input stream now
git-svn-id: svn://ttmath.org/publicrep/ezc/trunk@333 e52654a7-88a9-db11-a3e9-0013d4bc506e