[GRASS-dev] New wiki page summarising GRASS APIs

[Moritz Lennert]

On 01/02/15 21:22, Vaclav Petras wrote:
>
>
> On Sun, Feb 1, 2015 at 2:26 PM, Moritz Lennert
> <mlennert at club.worldonline.be <mailto:mlennert at club.worldonline.be>> wrote:
>
>     On 01/02/15 12:29, Glynn Clements wrote:
>
>
>         Pietro wrote:
>
>             {{{
>             import os
>             os.system('g.region rast=elevation')
>             }}}
>
>             and not subprocess:
>
>             {{{
>             import subprocess
>             subprocess.call('g.region rast=elevation', shell=True)
>
>             # or
>
>             subprocess.Popen('g.region rast=elevation', shell=True)
>             }}}
>
>             Concerning the pygrass Module API, may be we can use the
>             shortcut version:
>
>
>         Using subprocess.call() with shell=True is no better than using
>         os.system(). Both should be avoided at all costs.
>
>         The grass.script module provides a number of convenience functions
>         which use grass.script.make_command() to generate the command's
>         argument list from the function's argument list. Also, they use a
>         version of subprocess.Popen() which has been wrapped to deal
>         with some
>         of Windows' idiosyncrasies.
>
>
>
>     Just to be clear: the example on this wiki page shows just that it
>     is possible to call any GRASS module from any language that allows
>     system calls. It then goes on to introduce the scripting API to show
>     how that eases things on the script writer since she doesn't have to
>     deal with any idiosyncrasies.
>
>     But if this causes too much opposition I can take it out or at least
>     put a big warning of likes of "Don't use this ! Example code only."
>
>
> I suggest to use Bash example instead of Python one because this is how
> it is actually (also) used.

Well, there's no real syntax for a GRASS module call from Bash, you just 
do it, so the first example on the page can actually be considered a 
Bash example...

>
> If some warning is needed, it probably applies to all, Bash, C system
> calls and Perl too.

Maybe I should just erase all examples, just leaving the information 
that you can call GRASS modules via system calls if you know what you 
are doing.

For now, I've added a warning that you should know what you are doing if 
you want to use these calls.

>
> Do you consider a section for 3rd party APIs? Particularly I'm asking
> about spgrass in R (the same philosophy as grass.script for Python) and
> QGIS Processing (wrapper, limited functionality?, different philosophy).

Good idea. I just added a section linking to these two. I don't have 
much time these days to add anything else on them. So anyone who does, 
feel free.

Moritz