global variables

[John W. Eaton]

On  9-Feb-2009, Luis A. Montes wrote:

| I'm having a strange problem with global variables. Searched the list
| but nothing seems to show up. Mind you that I'm a rather sporadic user
| of octave (or Matlab, for that matter), I was just trying to import some
| Matlab scripts to Octave running under Linux (Ubuntu Hardy) when I got
| the following:
| 
| octave script.m
| GNU Octave, version 3.0.0
| Copyright (C) 2007 John W. Eaton and others.
| [...]
| 
| parse error near line 3 of file p10_1.m
| 
|   syntax error
| 
| >>> global cost hr hx grid N N_2;
|                                        ^
| 
| If I split the global declaration at the caret position so that I have:
| 
| global cost hr hx grid;
| global N N_2;
| 
| Then the syntax error goes away. I also renamed N variables to a longer
| name thinking that they could be clashing with other "default" global
| variables, but no dice.
| 
| I don't understand the problem or the solution, so I'm wondering if
| there is a less obvious problem with the second form that will cause the
| script to fail in more subtle ways.

The problem is with the use of the name "grid", which is Octave is
treated specially by the parser because it is a "command" name and may
be used like

  grid on

intead of

  grid ("on")

But it is a bug, because in this context, Octave should not be
recongnizing grid as a command name.

jwe