Re: [Orgmode] thoughts: "formulas for timestamps" feature

[Carsten Dominik]

On Jun 1, 2007, at 16:20, Ruslan Kosolapov wrote:

> Hi all, it's me again :)
>
> My previous message
> (http://www.mail-archive.com/address@hidden/msg01685.html)
> contains complains about ability to use formulas for timestamp (third
> problem).
>
> Yesterday I found http://www.cs.brown.edu/~gmarceau/spread.el
>
> I think it is what I need.  But one small problem blocks me.
>
> In org-file I wrote:
> ** NEW Task1
>    DEADLINE: qwe <= (concat "<2007-05-15 Втр>") => task1
>
> After M-x spread-recalc org file goes to:
> ** NEW Task1
>    DEADLINE: "<2007-05-15 Втр>" <= (concat "<2007-05-15 Втр>") => task1
>
> But agenda do not determine dates in quotes (btw, shift-up works
> well).
>
> I see two solutions:
>  - fix regexp of dates determination for quotes support (in org-mode)

I would recommend against this.  I am not sure what this would break,
but it may very well break something.

>  - fix spread-mode - remove quotes printing
>
> I tried to fix spread-mode, and fail (there are many reasons of it).
>
> 1. Does org-mode uses symbols "<=" and "=>"?

Yes, => is used in CLOCK lines, and in tables (but there only as
a display property).

> 2. Does org-mode contains functions for timestamp calculation?  I need
> something like
> (add-to-timestamp "<2007-05-15 Втр>" "+1d") with result "<2007-05-16 
> Срд>"

Org itself uses time-date.el.  There are no functions which would make
this easy - but it could be easy to write one - base it
on org-timestamp-change, but make it read and return strings.

- Carsten