Elisp: help on string operations

[Karl Voit <devnull@Karl-Voit.at>]

Hi!

For Memacs[1], I'd like to come up with a very fast Org-mode method to
open files independent of their location on your disk. I accomplished
everything necessary so far. However, I've got issues writing an elisp
function for extracting a file and sending it to a function that calls
the operating system app associated. My elisp knowledge is still too
bad :-(

What I've got is a string (from the lookup) which contains:
(1) nothing
(2) one line like "** <2008-06-17 21:43> [[file:/home/user/dir/2008-06-17 description of file.odp][2008-06-17 description of file.odp]]"
(3) multiple lines like (2) but with different files and links

I'd like to get a "Sorry" message for (1). Easy, if only I know how to
count lines in strings (as opposed to buffers).

For (2) I'd like to call my-open-in-external-app(string).

For (3), I'd like to use the first line just as in (2) as a starter. I
do have some ideas on gracious "error-recovering" on this one but
that's maybe too complicated to code for now: getting rid of
substrings delimited by not-'a-zA-Z0-9' from the end of the link
until a match is found; message in case there is no unique match which
could be found this way.

Could you please help me here?



The fragment I have so far is following but the regex seems to be
broken:

#+BEGIN_SRC elisp
    (let (
      (result (replace-regexp-in-string "\r?\n$" ""
                        (shell-command-to-string (concat "grep "
                                         "2008-06-17"
                                         " ~/org/memacs/files.org_archive")
                                     )
                        )
          )
      )
      (message (concat "result -> " result))
      (re-search-forward " \[\[.+\]\[" nil t 1)
      (let (
        (firstlink ((match-string 1)))
        )
        (message (concat "first link -> " firstlink))
       )
      )
#+END_SRC



[1] https://github.com/novoid/Memacs

-- 
All in all, one of the most disturbing things today is the definitive
fact that the NSA, GCHQ, and many more government organizations are
massively terrorizing the freedom of us and the next generations.
                                                  http://Karl-Voit.at