[libcamera-devel] [PATCH] cam: options: optional arguments needs to be specified as --foo=bar

[Niklas Söderlund]

Hi Laurent,

On 2019-01-25 13:01:34 +0200, Laurent Pinchart wrote:
> Hi Niklas,
> 
> On Fri, Jan 25, 2019 at 12:23:11AM +0100, Niklas Söderlund wrote:
> > It's not state in the documentation but optional arguments needs to be
> > specified using as '--foo=bar' instead of '--foo bar', otherwise the
> > value is not propagated to optarg during argument parsing. Update the
> > usage printing helper to reflect this requirement.
> > 
> > Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> > ---
> >  src/cam/options.cpp | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/src/cam/options.cpp b/src/cam/options.cpp
> > index 82acff9bbeea476d..73d81d0bc0ec6d38 100644
> > --- a/src/cam/options.cpp
> > +++ b/src/cam/options.cpp
> > @@ -143,7 +143,8 @@ void OptionsParser::usage()
> >  		};
> >  
> >  		if (option.argument != ArgumentNone) {
> > -			argument += std::string(" ");
> > +			argument += option.argument == ArgumentOptional ?
> > +				"=" : " ";
> >  			if (option.argument == ArgumentOptional)
> >  				argument += "[";
> >  			argument += option.argumentName;
> 
> This will output
> 
> 	-f, --foo value
> 
> for mandatory arguments, and
> 
> 	-f, --foo=[value]
> 
> for optional arguments. If we want to print the =, shouldn't it be
> --foo[=value] ?

It should of course be --foo[=value], will fix.

> And how should we handle the case where no long option
> is available, with this patch -f=[value] would be printed, which isn't
> correct I think.

Good point, for optional short arguments the syntax would be -fvalue.  
Would it make sens to print both short and long syntax in the usage?

    -f[value], --foo[=value]

Let me know what you think and I send a v2.

-- 
Regards,
Niklas Söderlund