Elisp: help on string operations

[Karl Voit]

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

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