editing an erroneous m file in Octave 3.2

[John W. Eaton]

On 14-Jun-2009, Michael Grossbach wrote:

| --------
| Bug report for Octave 3.2.0 configured for i486-pc-linux-gnu
| 
| Description:
| -----------
| When trying to edit a function file that has errors in it the file isn't
| opened in the editor. Instead Octave returns the error lines as if the
| file had been invoked.
| 
| Repeat-By:
| ---------
| Call the function file mgtest from the command line. mgtest shouldt
| contain erroneous Octave code, eg.
| function mgtest
| n =
| endfunction

The problem is that

   exist ("mgtest")

is trying to load the function and failing, and the error is not
handled.

I checked in the following change:

  http://hg.savannah.gnu.org/hgweb/octave/rev/c58b8960c7d0

Something like this should maybe be applied to the 3.2.x source tree,
but because of changes to the unwind_protect mechanism since 3.2.0 was
released, this patch will not apply cleanly.

jwe