[GRASS5] Re: 5.1: --html-description to parser added

[Glynn Clements]

Markus Neteler wrote:

> > > Is there a better way than faking a GRASS session (hope so!)?
> > 
> > Ultimately most of G_gisinit() ought to be moved to G_parser(); but
> > that would require that everything actually used G_parser(), which
> > isn't the case at present.
> 
> Correct. In general it may be interesting to have 'parser'
> as program for script usage (so that we don't have to build a
> parser any more with shell commands) which provides parameters
> and flags as
> PARAM1
> PARAM2 ..
> FLAG1 ...
> 
> for further usage in a script.

See src/general/g.parser; it really needs some documentation, though.

> > There are some other problems. E.g. some modules call G_get_window(),
> > R_open_driver() etc and initialise the defaults based upon data from
> > the current region or the monitor. This is (arguably) OK if the user
> > is running "g.foo help" interactively, but it means that the defaults
> > in the HTML file will reflect the session which was used to generate
> > it.
> 
> That's another point against a fake session. If the (updated) parser 
> got a flag to run without a GRASS session, it could be used in
> Makefile and above problem should be minimized.

Yes, but this requires finding and fixing all of the programs which
call GRASS functions prior to G_parser(). FWIW, I've discussed this
previously:

	From: Glynn Clements <glynn.clements at virgin.net>
	Message-ID: <15135.13549.677759.452840 at cerise.nosuchdomain.co.uk>
	Date: Thu, 7 Jun 2001 09:01:49 +0100
	Subject: Re: [GRASS5] Darwin Pre1 gtty stty errors

This mentions the following programs as using raster/display functions
to initialise defaults (so they fail if no monitor is selected):

	d.colors	- D_get_cell_name
	d.pan		- D_get_cell_list, D_get_dig_list, D_get_site_list
	d.save		- R_screen_{top,bot,left,rite}, R_pad_list, R_pad_select
	d.what.rast	- D_get_cell_list
	d.what.sites	- D_get_site_list
	d.what.vect	- D_get_dig_list
	d.zoom		- D_get_cell_list, D_get_dig_list, D_get_site_list

Also:

	From: Glynn Clements <glynn.clements at virgin.net>
	Message-ID: <15163.33358.71553.232455 at cerise.nosuchdomain.co.uk>
	Date: Thu, 28 Jun 2001 20:15:26 +0100
	Subject: Re: [GRASS5] Interfaces ... (long)

This mentions specific classes of problem, but not the individual
programs:

	1. D_get_cell_name (d.colors), D_get_{cell,dig,site}_list (several
	programs) and other functions (d.save) to obtain state from the
	monitor.
	
	2. G_gisbase, G_mapset, G_projection, G_zone, G_get_window and
	G_get_set_window to obtain information about the current location.
	
	3. spheroid_list and datum_list. In the case of spheroid_list, many
	programs implement this function independently.
	
	4. G_{lat,lon}_format_string, D_color_list. These functions actually
	just return string literals.
	
	5. read_list (used by g.{copy,list,remove,rename} to parse
	etc/element_list).

1 and 2 are the real problems here; they won't work without a session,
1 won't work without a monitor, and both will produce
--interface-description (etc) messages which are specific to the
session in which they are run.

Some alternative mechanims were proposed in the messages referenced
above.

-- 
Glynn Clements <glynn.clements at virgin.net>