[GRASS-dev] g.list -a

[Glynn Clements]

Martin Landa wrote:

> > +       if (G_parser(argc, argv))
> > +       {
> > +               fprintf (stderr, _("\nWhere %s is one of:\n"), element->key);
> > +               show_elements();
> > +               exit(EXIT_FAILURE);
> > +       }
> >
> > If G_parser() fails, the program should just call exit(EXIT_FAILURE);
> > G_parser() will print an error message detailing why it failed.
> 
> Yes, but the function show_elements() provides the user additional
> information why it failed. Would you like to remove it (maybe I have
> missed something)?
> 
> Where type is one of:
>   rast      (raster files)
>   rast3d    (raster3D files)
>   vect      (binary vector files)
>   oldvect   (old (GRASS 5.0) binary vector files)
>   asciivect (ascii vector files)
>   icon      (paint icon files)
>   labels    (paint label files)
>   sites     (site list files)
>   region    (region definition files)
>   region3d  (region3D definition files)
>   group     (imagery group files)
>   3dview    (3D view parameters)

The built-in error handling will display the following message:

Error: value <foo> out of range for parameter <type>
       Legal range: rast,rast3d,vect,oldvect,asciivect,icon,labels,sites,region,region3d,group,3dview

IMHO, this is sufficient. Note that the type descriptions *aren't*
shown if you use "g.list help", only if there is a parsing error
(which isn't limited to an invalid value for the type= option).

OTOH, I'm not really that bothered about this issue; assuming that it
compiles okay, I'll commit your latest version.

> > > > lib/do_list.c doesn't need to change; just have cmd/list.c call
> > > > do_list() once for each type.
> > >
> > > I think that fn do_list() have to be rewritten because of the -f flags
> > > (calling of execl() fn) ?
> >
> > No; do_list() can remain untouched, while the handling of -f should
> > remain essentially the same, except that it should use G_spawn()
> > instead of execl().
> 
> Ops, you are right. Maybe I need study GRASS API more deeply:-) Thanks
> for pointing to the G_spawn! Now it works.

FWIW, I've added a native Windows version of G_spawn(), although I
haven't had chance to test it yet.

-- 
Glynn Clements <glynn at gclements.plus.com>