[GRASS-dev] Re: 'g.gui wxpython' won't work in wingrass as wxgui is a shell script

[Ivan Shmakov]

>>>>> Ivan Shmakov <ivan at theory.asu.ru> writes:
>>>>> Michael Barton <michael.barton at asu.edu> writes:

[...]

 >> What this means is that we need to have Python people volunteer to
 >> begin to rewrite existing Bash scripts in Python and begin writing
 >> any new scripts in that platform so that we can have the critical
 >> mass to encourage others to learn it and write in it. A couple
 >> people have started on this.

 > I'm afraid that an attempt to rewrite /all/ the Shell scripts in
 > Python will both take time and bring some mess along.  Would you,
 > e. g., consider an untested 100-lines Python substitute for a
 > 50-lines Shell script (that's known to be working for years) to
 > encourage anyone to write in Python?

 > If there're particular strong points of Python, they're to be
 > exploited first (is wxPython among the others?)

	I may sound obvious here, but one more strong point could be
	added almost for free by exploiting an extended G_parser ().
	Namely, in order to ease the creation of ``smart'' wrappers, it
	may be allowed to introspect a GRASS module's CLI from Python.

	Furthermore, with introduction of an additional field, it may be
	allowed for a GRASS module to advertise its ``linearity'' on a
	particular field or fields.  E. g., the following are
	equivalent:

$ g.remove rast=foo,bar,baz
$ g.remove rast=foo,bar ; g.remove rast=baz

	Thus a ``smart'' wrapper for `g.remove' should be allowed to run
	`g.remove' on ``chunks'' of a sufficiently large list to
	overcome the OS command line limits (if any.)

	Some ``smart'' wrappers for `g.mlist' and `r.mapcalc' would
	allow for something like:

   for rast in grass.g.mlist (["rast"], "2008-*-temperature"]):
       grass.r.mapcalc ("%s-celsius" % rast, "\"%s\" - 273.15" % rast)

	(BTW, does Python allow associative lists, or named arguments?)

	And there should be a module allowing one to use a Python
	function to perform raster arithmetic (like `r.mapcalc'), too.

	Surely, there're many other things that could be done to make
	Python quite a sophisticated platform for GRASS scripting.  And
	I'm not certain that the time used to rewrite all the existing
	Shell scripts in Python cannot be spent better.