Determine actually given command line arguments

[Henry Leyh]

On 16.05.2013 08:08, Jussi Piitulainen wrote:
> Henry Leyh writes:
>
>> But now I would also like to be able to _write_ such a config file
>> FILE that can be read in a later run.  And FILE should contain only
>> those arguments that were given on the command line.
>>
>> Say, I tell argparse to look for arguments -s|--sopt STRING,
>> -i|--iopt INT, -b|--bopt [BOOL], -C CONFFILE.  Then 'prog -s bla -i
>> 42 -C cfile' should produce a confparser compatible cfile which
>> contains
>>
>>     [my_options]
>>     sopt = blah
>>     iopt = 42
>>
>> and not 'bopt = False' (if False was the program's default for
>> bopt).
>
> Could you instead write those options that differ from the defaults?
> You could parse an actual command line and an empty command line, and
> work out the difference.
>
> So 'prog -i 3' would not cause 'iopt = 3' to be written if 3 is the
> default for iopt, but would that be a problem?

That's what the program does at the moment.  However, I'm not quite 
happy with it.  Generally, the user doesn't know what's the default and 
it would be confusing if 'prog -i 3' doesn't make 'iopt = 3' turn up in 
the file at the end.  There may also be the case when the user (for 
whatever reason) _wants_ the default in the file.

I think I will try the opposite instead: the program writes the whole 
set of options to the file.  This would produce a complete and 
consistent configuration which automatically reflects the hierarchy in 
which the options were set.  And the user can sort it out by hand if he 
wants.

Regards,
Henry