Hi Andrea,
the double-dash options are generic options available for every module
and not defined by the module: --overwrite, --verbose, --quiet. These
options are used to set global environment variables. Using
r.watershed as example, it could be called through python with e.g.
grass.run_command("r.watershed", elevation = input, accumulation =
output, flags = 'a', overwrite = True, verbose = True)
Some modules, e.g. some of the import modules, have their own
(single-dash) -o flag, where
v.in.ogr -o --o
means "override projection check and overwrite output if existing"
IOW, you could ignore these three double-dash options when handling
flags of interface descriptions because they are available for every
module and not module-specific, if that makes your life easier in
generating wrappers.
HTH,
Markus M
On Tue, May 24, 2011 at 9:23 PM, andrea antonello
<andrea.antonello at gmail.com> wrote:
> My only guess here is that single character flags have a single dash
> and multiple character flags a double dash?
>
> Andrea
>
> On Tue, May 24, 2011 at 9:12 PM, andrea antonello
> <andrea.antonello at gmail.com> wrote:
>> Hi all,
>> I have a problem with the handling of flags in the interface description.
>>
>> Let's take for example pieces of r.watershed,
>> The help tells me:
>> [...]
>> -a Use positive flow accumulation even for likely underestimates
>> See manual for a detailed description of flow accumulation output
>> --o Allow output files to overwrite existing files
>> [...]
>>
>> and the interface description:
>> [...]
>>
>> <flag name="a">
>> <label>
>> Use positive flow accumulation even for likely underestimates
>> </label>
>> <description>
>> See manual for a detailed description of flow accumulation output
>> </description>
>> </flag>
>> <flag name="overwrite">
>> <description>
>> Allow output files to overwrite existing files
>> </description>
>> </flag>
>> [...]
>>
>> I can't find a way to understand why the first has one single dash,
>> while the overwrite flag needs two.
>> Any hints?
>>
>> Thanks,
>> Andrea
>>
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