[gdal-dev] Using a "standard" argument parser for command line utilities?

[Even Rouault]

Hi,

Our command line C++ utilities use ad-hoc manual parsing, which means that:

-  the usage message must be manually composed,

-  you must take care to check that there are enough remaining arguments 
for the ones that take value to avoid out-of-bounds accesses (tests like 
argc + 1 < argn)

- detection for duplicated arguments when only a single occurrence is 
allowed must be manually done, nd thus is often not done, confusing 
users, cf https://github.com/OSGeo/gdal/issues/9415

- etc.

I've come across https://github.com/p-ranav/argparse which fit all my 
requirements at first sight: compatible with our C++ requirements 
(C++17), MIT license, easily usable (single header), well documented, 
and enough feature-full. From a quick testing, it seems to work well. It 
looks also as it has taken some inspiration from the Python argparse module.

I'd be tempted to give that a try to retrofit our existing utilities 
(probably starting with the ones with the less options :-)). Opinions? I 
guess there must be a plethora of similar projects, due to the absence 
of a std::argparse module... At least I see it is in the list of (9) 
alternatives mentioned at 
https://en.cppreference.com/w/cpp/links/libs?source=post_page---------------------------#Configuration:Command_Line

CLI11 looked like a candidate too, but reading 
https://github.com/CLIUtils/CLI11?tab=readme-ov-file#features-not-supported-by-this-library 
"There are some other possible "features" that are intentionally not 
supported by this library:... Non-standard variations on syntax, like 
|-long| options. This is non-standard and should be avoided, so that is 
enforced by this library." . Fair enough, but we use that extensively in 
GDAL.

Even

-- 
http://www.spatialys.com
My software is free, but my time generally not.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20240308/5b784552/attachment.htm>