Re: Print out my key-sequences

[Kevin Rodgers]

Andrea Crotti wrote:
> Lennart Borgman <lennart.borgman@gmail.com> writes:
>
> > On Sun, Apr 18, 2010 at 11:01 AM, Andrea Crotti
> >
> > last-command => this-command-keys, this-command-keys-vector
> >
> > You can find this information by searching in the elisp manual with
> > isearch for "last-command".
> >
> > See also key-description.
>
> Great I think this is what I was looking for : (this-command-keys)
>
> Now I have this but I'm still getting an error
> --8<---------------cut here---------------start------------->8---
> (defun growl-popup (msg)
>   "Show a popup using growl notification or say it, only working on OSX with 
> growlnotify in the $PATH"
>   (interactive)
>   (if window-system
>       (shell-command (concat "growlnotify -a /Applications/Emacs.app/ -m " msg))
>     (message msg)))
>
> (defun popup-last ()
>   (interactive)
>   (growl-popup (this-command-keys)))
> --8<---------------cut here---------------end--------------->8---
>
> What doest that supposed to mean?
> The function this-command-keys is returning a string, and growl-popup is
> working just fine, so what could be the problem again?

this-command-keys may return a string or a vector, but concat returns a
string.

> --8<---------------cut here---------------start------------->8---
> (Shell command killed by signal Trace/BPT trap)
> --8<---------------cut here---------------end--------------->8---

this-command-keys can return a vector containing elements other than
integers (characters) e.g. symbols for function keys and mouse events.  And
the vector can contain integers that cannot be put into a string.  See
the Strings of Events node of the Emacs Lisp manual.

So first you have to find a robust way of converting the result of
this-command-keys to a string, so it can incorporated into the COMMAND
string argument to shell-command.  As Lennart suggested, key-description
is probably the way to go.

And passing an arbitrary string as an argument to a program via
shell-command is itself risky, if it may contain a shell metacharacters
(which seems quite likely in this case).  So the string should be escaped
using shell-quote-argument, or you could use call-process instead of
shell-command to avoid the quoting issue.

So:

(defun growl-popup (msg)
  "Pop up a growl notification with MSG, or display an Emacs message.
The \"growlnotify\" program is used if `window-system' is non-nil and
the program is found in `exec-path'; otherwise `message' is used."
  (interactive)
  (if (and window-system (executable-find "growlnotify"))
      (shell-command (concat "growlnotify -a /Applications/Emacs.app/ -m "
                             (shell-quote-argument msg)))
    (message msg)))

(defun popup-last ()
  (interactive)
  (growl-popup (key-description (this-command-keys))))

--
Kevin Rodgers
Denver, Colorado, USA