Re: org table calc and lisp for hh:mm timetable

[Carsten Dominik <carsten.dominik@gmail.com>]

On 22.3.2011, at 05:40, Eric Schulte wrote:

>> 
>> While this topic is raised, would it make sense for Org-mode table
>> formula to automatically parse any time-like string into time units
>> (i.e., base sixty).  That would be the easiest for most users, and (I
>> imagine) would rarely result in surprising and unexpected behavior.
>> 
> 
> So, I took a shot at folding this into org-table.el, the resulting patch
> is attached.  I'm not sure if this sort of automatic interpretation of
> time-like strings into integers is a good idea, or if this is the best
> implementation (I'm not incredibly familiar with Org's table handling)
> but after a couple of simple tests the patch does seem to work.  For
> example the following...
> 
> | 2:30 | 2 | 75 |
> #+TBLFM: $3=$1/$2

I think it might be a bit bold to turn this on by default.
How about introducing another flag for the formula to turn
on time string processing like this? 

- Carsten

> 
> It may make sense to also include functionality for converting the
> result back into a time string, e.g.
> 
> #+begin_src emacs-lisp
>  (defun org-time-seconds-to-string (secs)
>    "Convert a number of seconds to a time string."
>    (cond ((>= secs 3600) (format-seconds "%h:%.2m:%.2s" secs))
>          ((>= secs 60) (format-seconds "%m:%.2s" secs))
>          (t (format-seconds "%s" secs))))
> #+end_src
> 
> | 2:30 | 2 | 1:15 |
> #+TBLFM: $3='(org-time-seconds-to-string (/ (string-to-number $1) (string-to-number $2)))
> 
> While the above is cumbersome, there may be a simpler syntax or
> convention -- e.g., whenever one of the inputs is a time string then the
> results are displayed as a time string.  Not sure what the best option
> is here, but thought this patch may spur some good suggestions.
> 
> Best -- Eric
> 
> From 76b416013ee4c9a492c8ddced57727215165c298 Mon Sep 17 00:00:00 2001
> From: Eric Schulte <schulte.eric@gmail.com>
> Date: Mon, 21 Mar 2011 19:43:19 -0600
> Subject: [PATCH] org-table: convert times to integers on table formula evaluation
> 
> * lisp/org-table.el (org-table-to-time): If cell contents look like a
>  time string, then converts to an integer.
>  (org-table-eval-formula): Convert times to integers on table formula
>  evaluation.
> ---
> lisp/org-table.el |   26 ++++++++++++++++++++++----
> 1 files changed, 22 insertions(+), 4 deletions(-)
> 
> diff --git a/lisp/org-table.el b/lisp/org-table.el
> index 3573032..3674b53 100644
> --- a/lisp/org-table.el
> +++ b/lisp/org-table.el
> @@ -2273,6 +2273,21 @@ of the new mark."
>     (cons var (cons value modes)))
>   modes)
> 
> +(defun org-table-to-time (s)
> +  "Convert cell to numerical time if contents look like a time string."
> +  (cond
> +   ((and (stringp s)
> +	 (string-match "\\([0-9]+\\):\\([0-9]+\\):\\([0-9]+\\)" s))
> +    (let ((hour (string-to-number (match-string 1 s)))
> +	  (min (string-to-number (match-string 2 s)))
> +	  (sec (string-to-number (match-string 3 s))))
> +      (+ (* hour 3600) (* min 60) sec)))
> +   ((and (stringp s)
> +	 (string-match "\\([0-9]+\\):\\([0-9]+\\)" s))
> +    (let ((min (string-to-number (match-string 1 s)))
> +	  (sec (string-to-number (match-string 2 s))))
> +      (+ (* min 60) sec)))))
> +
> (defun org-table-eval-formula (&optional arg equation
> 					 suppress-align suppress-const
> 					 suppress-store suppress-analysis)
> @@ -2369,10 +2384,13 @@ not overwrite the stored one."
> 	  (setq formula (org-table-formula-substitute-names formula)))
>       (setq orig (or (get-text-property 1 :orig-formula formula) "?"))
>       (while (> ndown 0)
> -	(setq fields (org-split-string
> -		      (org-no-properties
> -		       (buffer-substring (point-at-bol) (point-at-eol)))
> -		      " *| *"))
> +	(setq fields (mapcar (lambda (cell)
> +			       (let ((time (org-table-to-time cell)))
> +				 (if time (number-to-string time) cell)))
> +			     (org-split-string
> +			      (org-no-properties
> +			       (buffer-substring (point-at-bol) (point-at-eol)))
> +			      " *| *")))
> 	(if (eq numbers t)
> 	    (setq fields (mapcar
> 			  (lambda (x) (number-to-string (string-to-number x)))
> -- 
> 1.7.1
>