[O] [babel] adding a language - problems

[Thorsten]

Hi list, 
I'm on my way to add a new (intrpreted) lisp dialect to org-babel, but
encounter a few difficulties. Here is my little testprogramm:

---------------------
#+tblname: tbl1
| 1 | 2 | 3 |
|---+---+---|
| 4 | 5 | 6 |
| 7 | 8 | 9 |


# external evaluation (no session)
#+srcname: pico-calc
#+begin_src picolisp :var tab=tbl1 :results value :hlines no 
  (+ (caar tab) (caar (cdr tab)))
#+end_src

# org-babel-error output:
[/tmp/babel-22634XBd/picolisp-script-22634K-K:1] !? (display (prog (let
(tab '((1 2 3) (4 5 6) (7 8 9))) (+ (caar tab) (caar (cdr tab))))))
display -- Undefined


#  with session
#+srcname: pico-calc
#+begin_src picolisp :var tab=tbl1 :results value :hlines no :session "p1"
  (+ (caar tab) (caar (cdr tab)))
#+end_src

#+results: pico-calc
[finishes with no output]

# session buffer:
(prog (let (tab '((1 2 3) (4 5 6) (7 8 9))) 
(+ (caar tab) (caar (cdr tab)))) )
"org-babel-picolisp-eoe"
-> 5
: -> "org-babel-picolisp-eoe"

---------------

I do not know where undefined 'display' comes from in the error message
- seems to be a org-babel internal thing. What can I do about that,
where do I have to look?

The session evaluation works already, but there is a problem with the
eoe string. If I don't use it, Emacs hangs forever - waiting for the
session to return? If I use it, the right value is calculated, but not
returned - because the eoe string is evaluated after the source-body?

Thanks for any tips
Thorsten