How to define a function in Zile Lisp

[Thorsten Jolitz <tjolitz@googlemail.com>]

Hi List, 

I recently discovered that the nice small and fast Emacs clone GNU Zile
(“Zile Is Lossy Emacs”) can be customized in its own .zile file with a
small subset of Emacs Lisp called Zile Lisp.

,--------------------------------------------------------------------
| For customization, Zile uses its own limited configuration language
| known as Zile Lisp. Zile Lisp is a tiny subset of Emacs Lisp that
| consists of the Zile commands plus ‘setq’.
`--------------------------------------------------------------------

(from: http://www.emacswiki.org/emacs/Zile)

Now I wonder how I can write my own functions in Zile lisp without
'defun' and other special forms, and without something like 'progn'
e.g.? 

There is a pdf manual for zile (immediate download:
http://tinyurl.com/bpo8dyr) that lists all Zile commands, but I can't
find any examples of Zile Lisp beyond simple customization settings with
'setq'. 

So here is a question/challenge for the Emacs Lisp experts (maybe there
is even somebody on the list who used Zile Lisp before): 

How can I define a function (that is at least a sequence of Zile/Emacs
commands) only with 'setq' and the navigation/editing functions? and what
trick could simulate conditional execution when there are (apparently)
no conditionals in Zile Lisp?

Or is this question unreasonable, and the only reasonable way to add
functionality to Zile is to write it in C?

-- 
cheers,
Thorsten