Mode for output analysis

[Andrea Crotti]

I have a log file which looks something like this:

--8<---------------cut here---------------start------------->8---
28.250000: 

1: BEACON_EVENT_TRIGGERED(27)
1: BEACON_SENT
----------------------------------------
28.251000: 

3: BEACON_RECEIVED(1)
3: NEIGHBOUR_UPDATED(1)
2: BEACON_RECEIVED(1)
2: NEIGHBOUR_UPDATED(1)
0: BEACON_RECEIVED(1)
0: NEIGHBOUR_UPDATED(1)
--8<---------------cut here---------------end--------------->8---

only today for the first time I thought to actually display the output
in emacs instead of the shell, and I produced:

--8<---------------cut here---------------start------------->8---
(defun pad-show-results (rerun)
  "shows the results of the execution"
  (interactive "Mrerun?:\n")
  (let*
      ((script (if (null rerun) "./analyze.py" "./runner.py"))
       (cmd (concat "cd $PAD_DIR && " script " 1")))
    
    (if (buffer-live-p (get-buffer result-buffer-name))
        (kill-buffer (get-buffer result-buffer-name)))
    ;; maybe can popup always on the same external frame instead
    (pop-to-buffer "*pad-results*")
    (message  (concat "running command " cmd))
    (insert (shell-command-to-string cmd))
    (goto-line 0)
    (compilation-mode)))

(setq compile-command "cd $PAD_DIR && make -j4")

(defun compile-and-show ()
  "recompile and show the output of the new execution"
  (interactive)
  (recompile)
  ;; does the second command waits for the end of the first??
  (pad-show-results t))
--8<---------------cut here---------------end--------------->8---

first a couple of questions:
- is it possible to rewrite on an existing buffer (which is read-only)
  more easily than how I do (checking if exist, kill and then create a
  new one)?
- am I sure in compile-and-show that the second expression is evaluated
  after the compilation is over?
  By default the subprocess are synchronous right?

And then I finally realized that I can do much much better, for example
- jump to where the expression shown is logged
- filter over regular expression, node number etc

I think I'll have to use overlays maybe and some black magic, do you
have any advice or example of library which does something like this??