Re: [PATCH 0/4] Add variant type

[Andrew Burgess <aburgess@redhat.com>]

* Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> [2022-02-01 09:07:13 -0500]:

> I sometimes encounter situations where I think using std::variant would
> be useful.  The benefits would be to be able to use non-POD types in the
> alternatives, have them automatically constructed when making an
> alternative active, and automatically destructing them when switching to
> another alternative of destroying the variant.  Also, the validation of
> access to the alternatives, to prevent accessing an alternative that is
> not the current one.
> 
> However, std::variant is only available in C++17.  I suggest that we
> import a variant implementation to allow us to use it right now, a bit
> like we did for optional and string_view.  We could maybe import the
> implementation from libstdc++, like we did for these last two types, but
> that sounds really tedious (we would also want to import any tests).
> Instead, we can take advantage of a popular implementation distributed
> as a single header file.  I chose this one:
> 
>   https://github.com/martinmoene/variant-lite
> 
> because it is close to the std implementation, and the license (Boost
> Software License) is clear and compatible with the GPL v3.

Is this compatible with the copyright assignment requirement of
contributing to GDB?

I'm assuming copyright of that file is not assigned to FSF.

My concern would be, what if code was copied from that file into the
rest of GDB?  Does that cause us problems?

Not trying to cause problems, just making sure we've considered this.

Thanks,
Andrew