[O] org table calc and lisp for hh:mm timetable

[Martin Halder]

Hi all,

some words of warning: this was written by an Emacs, Org, Lisp and Calc 
newbie.. and congratulations on converting a vim user btw, org mode is great : )

I was trying to generate a simple table with time format "hh:mm" and auto 
calculate daily sum.. clocking working time was too much so I thought this 
would be easy but ended up with the following.. it works but is not beautiful 
(apply formula twice and same information multiple times) and I would like to 
get rid of the "hms", "hh" and "mm" columns and therefore call "hmconcat" 
directly somehow.. Any help is highly appreciated.. 

Thanks,
Martin

| Date             | Start | Lunch |  Back |   End |   Sum | hms       | hh | 
mm |
|------------------+-------+-------+-------+-------+-------+-----------+----+----|
| [2011-03-01 Tue] | 08:00 | 12:20 | 13:00 | 17:00 | 08:20 | 8@ 20' 0" |  8 | 
20 |
#+TBLFM: $6='(hmconcat $8 $9)::$7=time(<2010-01-01 $5>)-time(<2010-01-01 
$4>)+time(<2010-01-01 $3>)-time(<2010-01-01 $2>)::$8=hour($7)::$9=minute($7)

(defun hmconcat (hh mm) (interactive)
    (if (> (length hh) 1)
        (setq temp (concat hh ":")) (setq temp (concat "0" hh ":")))
    (if (> (length mm) 1)
        (concat temp mm) (concat temp "0" mm)))